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• Reflections from the Young Prisms

  - by Oracle OpenWorld Blog Team

   By Karen Shamban The Young Prisms began their musical journey in San Francisco, and it's here they return to bring their unique sound to the Oracle OpenWorld Music Festival.  We asked them to tell us their thoughts on music, performing, and what they like in an audience.  Here's what they had to say: Q. What do you like best about performing in front of a live audience?A. There are a lot of things to love about playing in front of people. The best part is definitely the nights when the energy the audience brings shows through. Although it always differs from city to city and person to person, when you play to a full house and people are really getting into it, it's like no other feeling.Q. How do you use technology in creating and delivering your music?A. Well, we actually use a lot more electronic components than people realize. Pretty much every string instrument played either live or on recording has been filtered through numerous electronic effects. Matt uses somewhere around 12 or 14 every time we play live. Giovanni has six. Most of our writing and demoing is done with drum sequencers and samplers too, so it's safe to say we use technology to our advantage in the writing process. Live is a bit different, since we keep it to the basics with guitars and acoustic drums. We also tend to use projections when we play live, so technology helps us do that fairly easily as well.Q. Do you prefer smaller, intimate venues or larger, louder ones?  Why?A. Couldn’t say we have a real preference in venue size. I mean, its always great to get to play through a massive killer sound system, but small venues when packed full are equally as special if not more so, because of the intimacy of it. Some of my favorite shows I've seen as an audience member/ fan have been at the smaller venues in San Francisco.Q. What about your fans surprises you?A. Sometimes the older guys are a surprise. We've played shows where there are more older guys in their 40s and 50s, who come and stare and take notes at our effects pedals. Then there are kids our age or in their 20s. Sometimes it's surprising to think that the older guys relate to what we're doing more than our peers and friends in our age group.Q. What about your live act surprises your fans?A. I think people are often surprised by how shy we can be. It feels like people expect us to be really rowdy and throw things and make really loud noises and get really aggressive on stage because some of the sounds we use can have an abrasive element to them. People expect Matt to have some kind of Kurt Cobain attitude, which he doesn’t at all. So it seems it surprises people to see musicians playing loud and noisy songs in their early and mid 20s being fairly tame and calm on stage.Q. There are going to be a lot of technical people (you could call them geeks) in the Oracle crowd -- what are they going to love about your performance?A. Hopefully most of them are pedal nerds like we are and like the previously mentioned “older dude crowd.” Besides that I hope they’d be into the projections and group of songs we're going to play for them.Q. What's new and different in the music you're making today, versus a year or two ago?A. I'd say there is more focus on the songwriting now and less of the noise today than last year. I think it's pretty evident on the new record compared to the last two. On the first two records we made as YP, we had another guitar player and songwriter who no longer plays with us. So the process in which we develop songs is different as well.Q. Have you been on tour recently? If so, what do you like about touring, and what do you dislike?A. Touring is amazing. Some people might tell you different if they've been doing it for what they'd call too long, but for us it's really a great chance to play for people who care about the music we're making and also to see and explore the world. Getting to visit so many different cities and explore so many different cultures is amazing. Of course we love getting into cultural foods too. Stefanie is a fashion geek so getting to go to New York as often as we do as well as getting to play in London and Paris is always especially fun for her.Q. Ever think about playing another kind of music? If so, what, and why?A. Never really thought about wanting to do anything drastically different. I think the style of music we play has a lot to do with the stuff we have been listening to both growing up and now. It wasn’t really a conscious decision to make sure it was a certain sound, so I'm not sure we've ever thought about doing a way different genre or whatever like electronic music or country. Although there have been times we've had conversations where we discuss possibly doing quiet sets or using the string synth sounds.Q. What are the top three things people should know about your music?A1. We like noise.A2. We use ambience and atmosphere as much as as we can.A3. Yes, the vocals are supposed to be mixed in with the guitars. Get more info: Oracle OpenWorld Music Festival Young Prisms

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• Anatomy of a .NET Assembly - CLR metadata 2

  - by Simon Cooper

  Before we look any further at the CLR metadata, we need a quick diversion to understand how the metadata is actually stored. Encoding table information As an example, we'll have a look at a row in the TypeDef table. According to the spec, each TypeDef consists of the following: Flags specifying various properties of the class, including visibility. The name of the type. The namespace of the type. What type this type extends. The field list of this type. The method list of this type. How is all this data actually represented? Offset & RID encoding Most assemblies don't need to use a 4 byte value to specify heap offsets and RIDs everywhere, however we can't hard-code every offset and RID to be 2 bytes long as there could conceivably be more than 65535 items in a heap or more than 65535 fields or types defined in an assembly. So heap offsets and RIDs are only represented in the full 4 bytes if it is required; in the header information at the top of the #~ stream are 3 bits indicating if the #Strings, #GUID, or #Blob heaps use 2 or 4 bytes (the #US stream is not accessed from metadata), and the rowcount of each table. If the rowcount for a particular table is greater than 65535 then all RIDs referencing that table throughout the metadata use 4 bytes, else only 2 bytes are used. Coded tokens Not every field in a table row references a single predefined table. For example, in the TypeDef extends field, a type can extend another TypeDef (a type in the same assembly), a TypeRef (a type in a different assembly), or a TypeSpec (an instantiation of a generic type). A token would have to be used to let us specify the table along with the RID. Tokens are always 4 bytes long; again, this is rather wasteful of space. Cutting the RID down to 2 bytes would make each token 3 bytes long, which isn't really an optimum size for computers to read from memory or disk. However, every use of a token in the metadata tables can only point to a limited subset of the metadata tables. For the extends field, we only need to be able to specify one of 3 tables, which we can do using 2 bits: 0x0: TypeDef 0x1: TypeRef 0x2: TypeSpec We could therefore compress the 4-byte token that would otherwise be needed into a coded token of type TypeDefOrRef. For each type of coded token, the least significant bits encode the table the token points to, and the rest of the bits encode the RID within that table. We can work out whether each type of coded token needs 2 or 4 bytes to represent it by working out whether the maximum RID of every table that the coded token type can point to will fit in the space available. The space available for the RID depends on the type of coded token; a TypeOrMethodDef coded token only needs 1 bit to specify the table, leaving 15 bits available for the RID before a 4-byte representation is needed, whereas a HasCustomAttribute coded token can point to one of 18 different tables, and so needs 5 bits to specify the table, only leaving 11 bits for the RID before 4 bytes are needed to represent that coded token type. For example, a 2-byte TypeDefOrRef coded token with the value 0x0321 has the following bit pattern: 0 3 2 1 0000 0011 0010 0001 The first two bits specify the table - TypeRef; the other bits specify the RID. Because we've used the first two bits, we've got to shift everything along two bits: 000000 1100 1000 This gives us a RID of 0xc8. If any one of the TypeDef, TypeRef or TypeSpec tables had more than 16383 rows (2^14 - 1), then 4 bytes would need to be used to represent all TypeDefOrRef coded tokens throughout the metadata tables. Lists The third representation we need to consider is 1-to-many references; each TypeDef refers to a list of FieldDef and MethodDef belonging to that type. If we were to specify every FieldDef and MethodDef individually then each TypeDef would be very large and a variable size, which isn't ideal. There is a way of specifying a list of references without explicitly specifying every item; if we order the MethodDef and FieldDef tables by the owning type, then the field list and method list in a TypeDef only have to be a single RID pointing at the first FieldDef or MethodDef belonging to that type; the end of the list can be inferred by the field list and method list RIDs of the next row in the TypeDef table. Going back to the TypeDef If we have a look back at the definition of a TypeDef, we end up with the following reprensentation for each row: Flags - always 4 bytes Name - a #Strings heap offset. Namespace - a #Strings heap offset. Extends - a TypeDefOrRef coded token. FieldList - a single RID to the FieldDef table. MethodList - a single RID to the MethodDef table. So, depending on the number of entries in the heaps and tables within the assembly, the rows in the TypeDef table can be as small as 14 bytes, or as large as 24 bytes. Now we've had a look at how information is encoded within the metadata tables, in the next post we can see how they are arranged on disk.

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• Diving into OpenStack Network Architecture - Part 2 - Basic Use Cases

  - by Ronen Kofman

    rkofman Normal rkofman 4 138 2014-06-05T03:38:00Z 2014-06-05T05:04:00Z 3 2735 15596 Oracle Corporation 129 36 18295 12.00 Clean Clean false false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} In the previous post we reviewed several network components including Open vSwitch, Network Namespaces, Linux Bridges and veth pairs. In this post we will take three simple use cases and see how those basic components come together to create a complete SDN solution in OpenStack. With those three use cases we will review almost the entire network setup and see how all the pieces work together. The use cases we will use are: 1.       Create network – what happens when we create network and how can we create multiple isolated networks 2.       Launch a VM – once we have networks we can launch VMs and connect them to networks. 3.       DHCP request from a VM – OpenStack can automatically assign IP addresses to VMs. This is done through local DHCP service controlled by OpenStack Neutron. We will see how this service runs and how does a DHCP request and response look like. In this post we will show connectivity, we will see how packets get from point A to point B. We first focus on how a configured deployment looks like and only later we will discuss how and when the configuration is created. Personally I found it very valuable to see the actual interfaces and how they connect to each other through examples and hands on experiments. After the end game is clear and we know how the connectivity works, in a later post, we will take a step back and explain how Neutron configures the components to be able to provide such connectivity.  We are going to get pretty technical shortly and I recommend trying these examples on your own deployment or using the Oracle OpenStack Tech Preview. Understanding these three use cases thoroughly and how to look at them will be very helpful when trying to debug a deployment in case something does not work. Use case #1: Create Network Create network is a simple operation it can be performed from the GUI or command line. When we create a network in OpenStack the network is only available to the tenant who created it or it could be defined as “shared” and then it can be used by all tenants. A network can have multiple subnets but for this demonstration purpose and for simplicity we will assume that each network has exactly one subnet. Creating a network from the command line will look like this: # neutron net-create net1 Created a new network: +---------------------------+--------------------------------------+ | Field                     | Value                                | +---------------------------+--------------------------------------+ | admin_state_up            | True                                 | | id                        | 5f833617-6179-4797-b7c0-7d420d84040c | | name                      | net1                                 | | provider:network_type     | vlan                                 | | provider:physical_network | default                              | | provider:segmentation_id  | 1000                                 | | shared                    | False                                | | status                    | ACTIVE                               | | subnets                   |                                      | | tenant_id                 | 9796e5145ee546508939cd49ad59d51f     | +---------------------------+--------------------------------------+ Creating a subnet for this network will look like this: # neutron subnet-create net1 10.10.10.0/24 Created a new subnet: +------------------+------------------------------------------------+ | Field            | Value                                          | +------------------+------------------------------------------------+ | allocation_pools | {"start": "10.10.10.2", "end": "10.10.10.254"} | | cidr             | 10.10.10.0/24                                  | | dns_nameservers  |                                                | | enable_dhcp      | True                                           | | gateway_ip       | 10.10.10.1                                     | | host_routes      |                                                | | id               | 2d7a0a58-0674-439a-ad23-d6471aaae9bc           | | ip_version       | 4                                              | | name             |                                                | | network_id       | 5f833617-6179-4797-b7c0-7d420d84040c           | | tenant_id        | 9796e5145ee546508939cd49ad59d51f               | +------------------+------------------------------------------------+ We now have a network and a subnet, on the network topology view this looks like this: Now let’s dive in and see what happened under the hood. Looking at the control node we will discover that a new namespace was created: # ip netns list qdhcp-5f833617-6179-4797-b7c0-7d420d84040c   The name of the namespace is qdhcp-<network id> (see above), let’s look into the namespace and see what’s in it: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo     inet6 ::1/128 scope host        valid_lft forever preferred_lft forever 12: tap26c9b807-7c: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN     link/ether fa:16:3e:1d:5c:81 brd ff:ff:ff:ff:ff:ff     inet 10.10.10.3/24 brd 10.10.10.255 scope global tap26c9b807-7c     inet6 fe80::f816:3eff:fe1d:5c81/64 scope link        valid_lft forever preferred_lft forever   We see two interfaces in the namespace, one is the loopback and the other one is an interface called “tap26c9b807-7c”. This interface has the IP address of 10.10.10.3 and it will also serve dhcp requests in a way we will see later. Let’s trace the connectivity of the “tap26c9b807-7c” interface from the namespace.  First stop is OVS, we see that the interface connects to bridge  “br-int” on OVS: # ovs-vsctl show 8a069c7c-ea05-4375-93e2-b9fc9e4b3ca1     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-ex         Port br-ex             Interface br-ex                 type: internal     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port "tap26c9b807-7c"             tag: 1             Interface "tap26c9b807-7c"                 type: internal         Port br-int             Interface br-int                 type: internal     ovs_version: "1.11.0"   In the picture above we have a veth pair which has two ends called “int-br-eth2” and "phy-br-eth2", this veth pair is used to connect two bridge in OVS "br-eth2" and "br-int". In the previous post we explained how to check the veth connectivity using the ethtool command. It shows that the two are indeed a pair: # ethtool -S int-br-eth2 NIC statistics:      peer_ifindex: 10 . .   #ip link . . 10: phy-br-eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 . . Note that “phy-br-eth2” is connected to a bridge called "br-eth2" and one of this bridge's interfaces is the physical link eth2. This means that the network which we have just created has created a namespace which is connected to the physical interface eth2. eth2 is the “VM network” the physical interface where all the virtual machines connect to where all the VMs are connected. About network isolation: OpenStack supports creation of multiple isolated networks and can use several mechanisms to isolate the networks from one another. The isolation mechanism can be VLANs, VxLANs or GRE tunnels, this is configured as part of the initial setup in our deployment we use VLANs. When using VLAN tagging as an isolation mechanism a VLAN tag is allocated by Neutron from a pre-defined VLAN tags pool and assigned to the newly created network. By provisioning VLAN tags to the networks Neutron allows creation of multiple isolated networks on the same physical link.  The big difference between this and other platforms is that the user does not have to deal with allocating and managing VLANs to networks. The VLAN allocation and provisioning is handled by Neutron which keeps track of the VLAN tags, and responsible for allocating and reclaiming VLAN tags. In the example above net1 has the VLAN tag 1000, this means that whenever a VM is created and connected to this network the packets from that VM will have to be tagged with VLAN tag 1000 to go on this particular network. This is true for namespace as well, if we would like to connect a namespace to a particular network we have to make sure that the packets to and from the namespace are correctly tagged when they reach the VM network. In the example above we see that the namespace interface “tap26c9b807-7c” has vlan tag 1 assigned to it, if we examine OVS we see that it has flows which modify VLAN tag 1 to VLAN tag 1000 when a packet goes to the VM network on eth2 and vice versa. We can see this using the dump-flows command on OVS for packets going to the VM network we see the modification done on br-eth2: #  ovs-ofctl dump-flows br-eth2 NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18669.401s, table=0, n_packets=857, n_bytes=163350, idle_age=25, priority=4,in_port=2,dl_vlan=1 actions=mod_vlan_vid:1000,NORMAL  cookie=0x0, duration=165108.226s, table=0, n_packets=14, n_bytes=1000, idle_age=5343, hard_age=65534, priority=2,in_port=2 actions=drop  cookie=0x0, duration=165109.813s, table=0, n_packets=1671, n_bytes=213304, idle_age=25, hard_age=65534, priority=1 actions=NORMAL   For packets coming from the interface to the namespace we see the following modification: #  ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18690.876s, table=0, n_packets=1610, n_bytes=210752, idle_age=1, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL  cookie=0x0, duration=165130.01s, table=0, n_packets=75, n_bytes=3686, idle_age=4212, hard_age=65534, priority=2,in_port=1 actions=drop  cookie=0x0, duration=165131.96s, table=0, n_packets=863, n_bytes=160727, idle_age=1, hard_age=65534, priority=1 actions=NORMAL   To summarize we can see that when a user creates a network Neutron creates a namespace and this namespace is connected through OVS to the “VM network”. OVS also takes care of tagging the packets from the namespace to the VM network with the correct VLAN tag and knows to modify the VLAN for packets coming from VM network to the namespace. Now let’s see what happens when a VM is launched and how it is connected to the “VM network”. Use case #2: Launch a VM Launching a VM can be done from Horizon or from the command line this is how we do it from Horizon: Attach the network: And Launch Once the virtual machine is up and running we can see the associated IP using the nova list command : # nova list +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | ID                                   | Name         | Status | Task State | Power State | Networks        | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | 3707ac87-4f5d-4349-b7ed-3a673f55e5e1 | Oracle Linux | ACTIVE | None       | Running     | net1=10.10.10.2 | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ The nova list command shows us that the VM is running and that the IP 10.10.10.2 is assigned to this VM. Let’s trace the connectivity from the VM to VM network on eth2 starting with the VM definition file. The configuration files of the VM including the virtual disk(s), in case of ephemeral storage, are stored on the compute node at/var/lib/nova/instances/<instance-id>/. Looking into the VM definition file ,libvirt.xml,  we see that the VM is connected to an interface called “tap53903a95-82” which is connected to a Linux bridge called “qbr53903a95-82”: <interface type="bridge">       <mac address="fa:16:3e:fe:c7:87"/>       <source bridge="qbr53903a95-82"/>       <target dev="tap53903a95-82"/>     </interface>   Looking at the bridge using the brctl show command we see this: # brctl show bridge name     bridge id               STP enabled     interfaces qbr53903a95-82          8000.7e7f3282b836       no              qvb53903a95-82                                                         tap53903a95-82    The bridge has two interfaces, one connected to the VM (“tap53903a95-82 “) and another one ( “qvb53903a95-82”) connected to “br-int” bridge on OVS: # ovs-vsctl show 83c42f80-77e9-46c8-8560-7697d76de51c     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-int         Port br-int             Interface br-int                 type: internal         Port "int-br-eth2"             Interface "int-br-eth2"         Port "qvo53903a95-82"             tag: 3             Interface "qvo53903a95-82"     ovs_version: "1.11.0"   As we showed earlier “br-int” is connected to “br-eth2” on OVS using the veth pair int-br-eth2,phy-br-eth2 and br-eth2 is connected to the physical interface eth2. The whole flow end to end looks like this: VM è tap53903a95-82 (virtual interface)è qbr53903a95-82 (Linux bridge) è qvb53903a95-82 (interface connected from Linux bridge to OVS bridge br-int) è int-br-eth2 (veth one end) è phy-br-eth2 (veth the other end) è eth2 physical interface. The purpose of the Linux Bridge connecting to the VM is to allow security group enforcement with iptables. Security groups are enforced at the edge point which are the interface of the VM, since iptables nnot be applied to OVS bridges we use Linux bridge to apply them. In the future we hope to see this Linux Bridge going away rules.  VLAN tags: As we discussed in the first use case net1 is using VLAN tag 1000, looking at OVS above we see that qvo41f1ebcf-7c is tagged with VLAN tag 3. The modification from VLAN tag 3 to 1000 as we go to the physical network is done by OVS  as part of the packet flow of br-eth2 in the same way we showed before. To summarize, when a VM is launched it is connected to the VM network through a chain of elements as described here. During the packet from VM to the network and back the VLAN tag is modified. Use case #3: Serving a DHCP request coming from the virtual machine In the previous use cases we have shown that both the namespace called dhcp-<some id> and the VM end up connecting to the physical interface eth2  on their respective nodes, both will tag their packets with VLAN tag 1000.We saw that the namespace has an interface with IP of 10.10.10.3. Since the VM and the namespace are connected to each other and have interfaces on the same subnet they can ping each other, in this picture we see a ping from the VM which was assigned 10.10.10.2 to the namespace: The fact that they are connected and can ping each other can become very handy when something doesn’t work right and we need to isolate the problem. In such case knowing that we should be able to ping from the VM to the namespace and back can be used to trace the disconnect using tcpdump or other monitoring tools. To serve DHCP requests coming from VMs on the network Neutron uses a Linux tool called “dnsmasq”,this is a lightweight DNS and DHCP service you can read more about it here. If we look at the dnsmasq on the control node with the ps command we see this: dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap26c9b807-7c --except-interface=lo --pid-file=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host --dhcp-optsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/opts --leasefile-ro --dhcp-range=tag0,10.10.10.0,static,120s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal The service connects to the tap interface in the namespace (“--interface=tap26c9b807-7c”), If we look at the hosts file we see this: # cat  /var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host fa:16:3e:fe:c7:87,host-10-10-10-2.openstacklocal,10.10.10.2   If you look at the console output above you can see the MAC address fa:16:3e:fe:c7:87 which is the VM MAC. This MAC address is mapped to IP 10.10.10.2 and so when a DHCP request comes with this MAC dnsmasq will return the 10.10.10.2.If we look into the namespace at the time we initiate a DHCP request from the VM (this can be done by simply restarting the network service in the VM) we see the following: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c tcpdump -n 19:27:12.191280 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:fe:c7:87, length 310 19:27:12.191666 IP 10.10.10.3.bootps > 10.10.10.2.bootpc: BOOTP/DHCP, Reply, length 325   To summarize, the DHCP service is handled by dnsmasq which is configured by Neutron to listen to the interface in the DHCP namespace. Neutron also configures dnsmasq with the combination of MAC and IP so when a DHCP request comes along it will receive the assigned IP. Summary In this post we relied on the components described in the previous post and saw how network connectivity is achieved using three simple use cases. These use cases gave a good view of the entire network stack and helped understand how an end to end connection is being made between a VM on a compute node and the DHCP namespace on the control node. One conclusion we can draw from what we saw here is that if we launch a VM and it is able to perform a DHCP request and receive a correct IP then there is reason to believe that the network is working as expected. We saw that a packet has to travel through a long list of components before reaching its destination and if it has done so successfully this means that many components are functioning properly. In the next post we will look at some more sophisticated services Neutron supports and see how they work. We will see that while there are some more components involved for the most part the concepts are the same. @RonenKofman

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• Error in my Separating Axis Theorem collision code

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• Application Composer: Exposing Your Customizations in BI Analytics and Reporting

  - by Richard Bingham

  Introduction This article explains in simple terms how to ensure the customizations and extensions you have made to your Fusion Applications are available for use in reporting and analytics. It also includes four embedded demo videos from our YouTube channel (if they don't appear check the browser address bar for a blocking shield icon). If you are new to Business Intelligence consider first reviewing our getting started article, and you can read more about the topic of custom subject areas in the documentation book Extending Sales. There are essentially four sections to this post. First we look at how custom fields added to standard objects are made available for reporting. Secondly we look at creating custom subject areas on the standard objects. Next we consider reporting on custom objects, starting with simple standalone objects, then child custom objects, and finally custom objects with relationships. Finally this article reviews how flexfields are exposed for reporting. Whilst this article applies to both Cloud/SaaS and on-premises deployments, if you are an on-premises developer then you can also use the BI Administration Tool to customize your BI metadata repository (the RPD) and create new subject areas. Whilst this is not covered here you can read more in Chapter 8 of the Extensibility Guide for Developers. Custom Fields on Standard Objects If you add a custom field to your standard object then it's likely you'll want to include it in your reports. This is very simple, since all new fields are instantly available in the "[objectName] Extension" folder in existing subject areas. The following two minute video demonstrates this. Custom Subject Areas for Standard Objects You can create your own subject areas for use in analytics and reporting via Application Composer. An example use-case could be to simplify the seeded subject areas, since they sometimes contain complex data fields and internal values that could confuse business users. One thing to note is that you cannot create subject areas in a sandbox, as it is not supported by BI, so once your custom object is tested and complete you'll need to publish the sandbox before moving forwards. The subject area creation processes is essentially two-fold. Once the request is submitted the ADF artifacts are generated, then secondly the related metadata is sent to the BI presentation server API's to make the updates there. One thing to note is that this second step may take up to ten minutes to complete. Once finished the status of the custom subject area request should show as 'OK' and it is then ready for use. Within the creation processes wizard-like steps there are three concepts worth highlighting: Date Flattening - this feature permits the roll up of reports at various date levels, such as data by week, month, quarter, or year. You simply check the box to enable it for that date field. Measures - these are your own functions that you can build into the custom subject area. They are related to the field data type and include min-max for dates, and sum(), avg(), and count() for  numeric fields. Implicit Facts - used to make the BI metadata join between your object fields and the calculated measure fields. The advice is to choose the most frequently used measure to ensure consistency. This video shows a simple example, where a simplified subject area is created for the customer 'Contact' standard object, picking just a few fields upon which users can then create reports. Custom Objects Custom subject areas support three types of custom objects. First is a simple standalone custom object and for which the same process mentioned above applies. The next is a custom child object created on a standard object parent, and finally a custom object that is related to a parent object - usually through a dynamic choice list. Whilst the steps in each of these last two are mostly the same, there are differences in the way you choose the objects and their fields. This is illustrated in the videos below.The first video shows the process for creating a custom subject area for a simple standalone custom object. This second video demonstrates how to create custom subject areas for custom objects that are of parent:child type, as well as those those with dynamic-choice-list relationships. &lt;span id=&quot;XinhaEditingPostion&quot;&gt;&lt;/span&gt; Flexfields Dynamic and Extensible Flexfields satisfy a similar requirement as custom fields (for Application Composer), with flexfields common across the Fusion Financials, Supply Chain and Procurement, and HCM applications. The basic principle is when you enable and configure your flexfields, in the edit page under each segment region (for both global and context segments) there is a BI Enabled check box. Once this is checked and you've completed your configuration, you run the Scheduled Process job named 'Import Oracle Fusion Data Extensions for Transactional Business Intelligence' to generate and migrate the related BI artifacts and data. This applies for dynamic, key, and extensible flexfields. Of course there is more to consider in terms of how you wish your flexfields to be implemented and exposed in your reports, and details are given in Chapter 4 of the Extending Applications guide.

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• ArchBeat Link-o-Rama for 2012-04-05

  - by Bob Rhubart

  Webcast: Oracle Maximum Availability Architecture Best Practices event.on24.com Date: Thursday, April 12, 2012 Time: 10:00 AM PDT Oracle expert Tom Kyte discusses how Oracle’s Maximum Availability Architecture can help to minimize the costs and risk of downtime. Oracle Enterprise Manager Ops Center 12c Launch - Interactive Webcast and Live Chat www.oracle.com Thursday, April 12, 2012. 9 a.m. PT / 12 p.m. ET / 4 p.m. GMT. Speakers: Steve Wilson (VP Systems Management, Oracle) John Fowler (Exec VP Systems, Oracle) Brad Cameron (VP Development, Oracle Fusion Middleware) Bill Nesheim (VP Oracle Solaris) Dennis Reno (VP Customer Portal Experience, Oracle) Mike Wookey (Chief Architect, Oracle Enterprise Manager Ops Center) Prasad Pai (Sr Director, Oracle Enterprise Manager Ops Center) 2012 Real World Performance Tour Dates |Performance Tuning | Performance Engineering www.ioug.org Coming to your town: a full day of real world database performance with Tom Kyte, Andrew Holdsworth, and Graham Wood. Rochester, NY - March 8 Los Angeles, CA - April 30 Orange County, CA - May 1 Redwood Shores, CA - May 3 Oracle Technology Network Developer Day: MySQL - New York www.oracle.com Wednesday, May 02, 2012 8:00 AM – 4:30 PM Grand Hyatt New York 109 East 42nd Street, Grand Central Terminal New York, NY 10017 Webcast Series: Data Warehousing Best Practices event.on24.com April 19, 2012 - Best Practices for Workload Management of a Data Warehouse on Oracle Exadata May 10, 2012 - Best Practices for Extreme Data Warehouse Performance on Oracle Exadata How to create a Global Rule that stores a document’s folder path in a custom metadata field | Nicolas Montoya blogs.oracle.com An illustrated how-to from Oracle Fusion Middleware A-Team blogger Nicolas Montoya. Get Proactive with Fusion Middleware | Daniel Mortimer blogs.oracle.com Daniel Mortimer shows how to access "a one stop shop for navigating to proactive support material, tools, and communication channels related to Oracle Fusion Middleware." Build an enterprise on 'other peoples' work', via SOA and cloud | Joe McKendrick www.zdnet.com Are you down with OPW? Joe McKendrick's synopsis of a recent presentation by David Linthicum focuses on reuse. Oracle Fusion Middleware Security: Unsolicited login with OAM 11g | Chris Johnson fusionsecurity.blogspot.com Chris Johnson shows how to create a shopping cart login model using "plain old HTML." How to use the Human WorkFlow Web Services | Edwin Biemond biemond.blogspot.com Oracle ACE Edwin Biemond shows how to invoke two WorkFlow web services to query the Human task in Oracle SOA Suite with your own ordering and restrictions. Bad Practice Use Case for LOV Performance Implementation in ADF BC | Andrejus Baranovskis andrejusb.blogspot.com "If you want to learn something well, there is nothing better [than] to learn bad practices first," says Oracle ACE Director Andrejus Baranovskis. Thought for the Day "The best meetings get real work done. When your people learn that your meetings actually accomplish something, they will stop making excuses to be elsewhere." — Larry Constantine

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• Using R to Analyze G1GC Log Files

  - by user12620111

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  Using R to Analyze G1GC Log Files   Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z\(\),]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\\( " , " " ); gsub ( "\ \)" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period:     par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight.   plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

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• Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

  - by MarkPearl

  After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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• Trouble with AABB collision response and physics

  - by WCM

  I have been racking my brain trying to figure out a problem I am having with physics and basic AABB collision response. I am fairly close as the physics are mostly right. Gravity feels good and movement is solid. The issue I am running into is that when I land on the test block in my project, I can jump off of it most of the time. If I repeatedly jump in place, I will eventually get stuck one or two pixels below the surface of the test block. If I try to jump, I can become free of the other block, but it will happen again a few jumps later. I feel like I am missing something really obvious with this. I have two functions that support the detection and function to return a vector for the overlap of the two rectangle bounding boxes. I have a single update method that is processing the physics and collision for the entity. I feel like I am missing something very simple, like an ordering of the physics vs. collision response handling. Any thoughts or help can be appreciated. I apologize for the format of the code, tis prototype code mostly. The collision detection function: public static bool Collides(Rectangle source, Rectangle target) { if (source.Right < target.Left || source.Bottom < target.Top || source.Left > target.Right || source.Top > target.Bottom) { return false; } return true; } The overlap function: public static Vector2 GetMinimumTranslation(Rectangle source, Rectangle target) { Vector2 mtd = new Vector2(); Vector2 amin = source.Min(); Vector2 amax = source.Max(); Vector2 bmin = target.Min(); Vector2 bmax = target.Max(); float left = (bmin.X - amax.X); float right = (bmax.X - amin.X); float top = (bmin.Y - amax.Y); float bottom = (bmax.Y - amin.Y); if (left > 0 || right < 0) return Vector2.Zero; if (top > 0 || bottom < 0) return Vector2.Zero; if (Math.Abs(left) < right) mtd.X = left; else mtd.X = right; if (Math.Abs(top) < bottom) mtd.Y = top; else mtd.Y = bottom; // 0 the axis with the largest mtd value. if (Math.Abs(mtd.X) < Math.Abs(mtd.Y)) mtd.Y = 0; else mtd.X = 0; return mtd; } The update routine (gravity = 0.001f, jumpHeight = 0.35f, moveAmount = 0.15f): public void Update(GameTime gameTime) { Acceleration.Y = gravity; Position += new Vector2((float)(movement * moveAmount * gameTime.ElapsedGameTime.TotalMilliseconds), (float)(Velocity.Y * gameTime.ElapsedGameTime.TotalMilliseconds)); Velocity.Y += Acceleration.Y; Vector2 previousPosition = new Vector2((int)Position.X, (int)Position.Y); KeyboardState keyboard = Keyboard.GetState(); movement = 0; if (keyboard.IsKeyDown(Keys.Left)) { movement -= 1; } if (keyboard.IsKeyDown(Keys.Right)) { movement += 1; } if (Position.Y + 16 > GameClass.Instance.GraphicsDevice.Viewport.Height) { Velocity.Y = 0; Position = new Vector2(Position.X, GameClass.Instance.GraphicsDevice.Viewport.Height - 16); IsOnSurface = true; } if (Collision.Collides(BoundingBox, GameClass.Instance.block.BoundingBox)) { Vector2 mtd = Collision.GetMinimumTranslation(BoundingBox, GameClass.Instance.block.BoundingBox); Position += mtd; Velocity.Y = 0; IsOnSurface = true; } if (keyboard.IsKeyDown(Keys.Space) && !previousKeyboard.IsKeyDown(Keys.Space)) { if (IsOnSurface) { Velocity.Y = -jumpHeight; IsOnSurface = false; } } previousKeyboard = keyboard; } This is also a full download to the project. https://www.box.com/s/3rkdtbso3xgfgc2asawy P.S. I know that I could do this with the XNA Platformer Starter Kit algo, but it has some deep flaws that I am going to try to live without. I'd rather go the route of collision response via an overlay function. Thanks for any and all insight!

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• NDepend Evaluation: Part 3

  - by Anthony Trudeau

  NDepend is a Visual Studio add-in designed for intense code analysis with the goal of high code quality. NDepend uses a number of metrics and aggregates the data in pleasing static and active visual reports. My evaluation of NDepend will be broken up into several different parts. In the first part of the evaluation I looked at installing the add-in.  And in the last part I went over my first impressions including an overview of the features.  In this installment I provide a little more detail on a few of the features that I really like. Dependency Matrix The dependency matrix is one of the rich visual components provided with NDepend.  At a glance it lets you know where you have coupling problems including cycles.  It does this with number indicating the weight of the dependency and a color-coding that indicates the nature of the dependency. Green and blue cells are direct dependencies (with the difference being whether the relationship is from row-to-column or column-to-row).  Black cells are the ones that you really want to know about.  These indicate that you have a cycle.  That is, type A refers to type B and type B also refers to Type A. But, that’s not the end of the story.  A handy pop-up appears when you hover over the cell in question.  It explains the color, the dependency, and provides several interesting links that will teach you more than you want to know about the dependency. You can double-click the problem cells to explode the dependency.  That will show the dependencies on a method-by-method basis allowing you to more easily target and fix the problem.  When you’re done you can click the back button on the toolbar. Dependency Graph The dependency graph is another component provided.  It’s complementary to the dependency matrix, but it isn’t as easy to identify dependency issues using the window. On a positive note, it does provide more information than the matrix. My biggest issue with the dependency graph is determining what is shown.  This was not readily obvious.  I ended up using the navigation buttons to get an acceptable view.  I would have liked to choose what I see. Once you see the types you want you can get a decent idea of coupling strength based on the width of the dependency lines.  Double-arrowed lines are problematic and are shown in red.  The size of the boxes will be related to the metric being displayed.  This is controlled using the Box Size drop-down in the toolbar.  Personally, I don’t find the size of the box to be helpful, so I change it to Constant Font. One nice thing about the display is that you can see the entire path of dependencies when you hover over a type.  This is done by color-coding the dependencies and dependants.  It would be nice if selecting the box for the type would lock the highlighting in place. I did find a perhaps unintended work-around to the color-coding.  You can lock the color-coding in by hovering over the type, right-clicking, and then clicking on the canvas area to clear the pop-up menu.  You can then do whatever with it including saving it to an image file with the color-coding. CQL NDepend uses a code query language (CQL) to work with your code just like it was a database.  CQL cannot be confused with the robustness of T-SQL or even LINQ, but it represents an impressive attempt at providing an expressive way to enumerate and interrogate your code. There are two main windows you’ll use when working with CQL.  The CQL Query Explorer allows you to define what queries (rules) are run as part of a report – I immediately unselected rules that I don’t want in my results.  The CQL Query Edit window is where you can view or author your own rules.  The explorer window is pretty self-explanatory, so I won’t mention it further other than to say that any queries you author will appear in the custom group. Authoring your own queries is really hard to screw-up.  The Intellisense-like pop-ups tell you what you can do while making composition easy.  I was able to create a query within two minutes of playing with the editor.  My query warns if any types that are interfaces don’t start with an “I”. WARN IF Count > 0 IN SELECT TYPES WHERE IsInterface AND !NameLike “I” The results from the CQL Query Edit window are immediate. That fact makes it useful for ad hoc querying.  It’s worth mentioning two things that could make the experience smoother.  First, out of habit from using Visual Studio I expect to be able to scroll and press Tab to select an item in the list (like Intellisense).  You have to press Enter when you scroll to the item you want.  Second, the commands are case-sensitive.  I don’t see a really good reason to enforce that. CQL has a lot of potential not just in enforcing code quality, but also enforcing architectural constraints that your enterprise has defined. Up Next My next update will be the final part of the evaluation.  I will summarize my experience and provide my conclusions on the NDepend add-in. ** View Part 1 of the Evaluation ** ** View Part 2 of the Evaluation ** Disclaimer: Patrick Smacchia contacted me about reviewing NDepend. I received a free license in return for sharing my experiences and talking about the capabilities of the add-in on this site. There is no expectation of a positive review elicited from the author of NDepend.

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• Is your dream an international experience?

  - by Maria Sandu

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Studying in Poland, having two summer jobs in England, doing one internship in India, working in Thailand for half a year and now working in Prague. Does it seem an adventure? Well it is and I will tell you how I came to have this international experience. Dzien Dobry! My name is Wojciech Jurojc, I am Polish and I am currently a Business Development Consultant within Oracle, based in Prague. I joined Oracle on the 1st of August 2011. I graduated in 2010 and obtained 2 Masters Degrees in Political Science and Economics. I would like to tell you more about my past and how I joined Oracle. In 2005 I began studying at the Faculty of Political Sciences Gdansk University. In 2008, I obtained a Bachelors Degree. During these three years I had the opportunity to go to England twice, where I worked as a Bartender, first in Blackpool and then in Manchester. This allowed me to improve my language skills and become more confident. In the meantime, I joined the International Student Organization-AIESEC, where I was organized conferences and conducted student projects. Also I met a mass of interesting people from around the world. After graduation in 2008, I was able to get an Internship within a big company in Poland. I worked there as an Intern in the Purchase Department. That was my first adventure within a corporate environment. I learnt a lot about purchasing processes and negotiations. In September 2008, I started studying two Masters Faculties: Political Science and Economics. It was very difficult, but it was not impossible. Over the next two years of studying I was able to go on a three month internship to India where I worked as a Marketing Assistant in an NGO. I was travelling around northern India and did presentations to the academic community about green energy and environmental projects. I had the opportunity to visit Nepal and walked in the Himalayas. That was a huge experience as well as a cultural shock. It taught me how to deal with many problems and to appreciate what I have. At the end of 2009 I was working as a Marketing Assistant for a Leasing company, where I learnt useful sales knowledge and improved my objection handling skills. In July 2010, I graduated with a double Masters and found a job in Thailand as Sales Representative in an IT company. I worked in Thailand until the end of January 2011. Besides that, I was working in an International company with interesting people and I had the opportunity to travel around Thailand and visit Cambodia. After this adventure I started looking for jobs in Europe where I could further develop my sales skills. I found Oracle and I don’t regret this decision which I made. I am currently working in Prague in an international Hardware team and I know that is not the end of my adventures. At this moment, I am working in a team of 12 members. Ten of them are based in Prague and 2 others are based in Russia. We come from different countries such as: Czech Republic, Russia, Ukraine, Turkey, Slovakia and Kazakhstan. I am working on the Polish market, cooperating with our Hardware customers and partners. What do I enjoy the most about my job? I enjoy every challenge that I face in my daily activities as there are always new experiences for me and new things that I learn. As part of Oracle, I gain international exposure and therefore more career opportunities to explore. I have planned my next step for the career path I dream of and I am currently working on it. I recommend you check our Career Page if you’re looking for an international career. If you want to find out more about our job opportunities, follow us on https://campus.oracle.com .

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• Data-Driven SOA with Oracle Data Integrator

  - by Irem Radzik

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Cambria","serif"; mso-fareast-font-family:"MS Mincho";} By Mike Eisterer, Data integration is more than simply moving data in bulk or in real-time, it is also about unifying information for improved business agility and integrating it in today’s service-oriented architectures. SOA enables organizations to easily define services which may then be discovered and leveraged by varying consumers. These consumers may be applications, customer facing portals, or complex business rules which are assembling services to automate process. Data as a foundational service provider is a key component of today’s successful SOA implementations. Oracle offers the broadest and most integrated portfolio of products to help you define, organize, orchestrate and consume data services. If you are attending Oracle OpenWorld next week, you will have ample opportunity to see the latest Oracle Data Integrator live in action and work with it yourself in two offered Hands-on Labs. Visit the hands-on lab to gain experience firsthand: Oracle Data Integrator and Oracle SOA Suite: Hands-on- Lab (HOL10480) Wed Oct 3rd 11:45AM Marriott Marquis- Salon 1/2 To learn more about Oracle Data Integrator, please visit our Introduction Hands-on LAB: Introduction to Oracle Data Integrator (HOL10481) Mon Oct 1st 3:15PM, Marriott Marquis- Salon 1/2 If you are not able to attend OpenWorld, please check out our latest resources for Data Integration.

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• Separating text strings into a table of individual words in SQL via XML.

  - by Phil Factor

  p.MsoNormal {margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; font-size:11.0pt; font-family:"Calibri","sans-serif"; } Nearly nine years ago, Mike Rorke of the SQL Server 2005 XML team blogged ‘Querying Over Constructed XML Using Sub-queries’. I remember reading it at the time without being able to think of a use for what he was demonstrating. Just a few weeks ago, whilst preparing my article on searching strings, I got out my trusty function for splitting strings into words and something reminded me of the old blog. I’d been trying to think of a way of using XML to split strings reliably into words. The routine I devised turned out to be slightly slower than the iterative word chop I’ve always used in the past, so I didn’t publish it. It was then I suddenly remembered the old routine. Here is my version of it. I’ve unwrapped it from its obvious home in a function or procedure just so it is easy to appreciate. What it does is to chop a text string into individual words using XQuery and the good old nodes() method. I’ve benchmarked it and it is quicker than any of the SQL ways of doing it that I know about. Obviously, you can’t use the trick I described here to do it, because it is awkward to use REPLACE() on 1…n characters of whitespace. I’ll carry on using my iterative function since it is able to tell me the location of each word as a character-offset from the start, and also because this method leaves punctuation in (removing it takes time!). However, I can see other uses for this in passing lists as input or output parameters, or as return values.   if exists (Select * from sys.xml_schema_collections where name like 'WordList')   drop XML SCHEMA COLLECTION WordList go create xml schema collection WordList as ' <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="words">        <xs:simpleType>               <xs:list itemType="xs:string" />        </xs:simpleType> </xs:element> </xs:schema>'   go   DECLARE @string VARCHAR(MAX) –we'll get some sample data from the great Ogden Nash Select @String='This is a song to celebrate banks, Because they are full of money and you go into them and all you hear is clinks and clanks, Or maybe a sound like the wind in the trees on the hills, Which is the rustling of the thousand dollar bills. Most bankers dwell in marble halls, Which they get to dwell in because they encourage deposits and discourage withdrawals, And particularly because they all observe one rule which woe betides the banker who fails to heed it, Which is you must never lend any money to anybody unless they don''t need it. I know you, you cautious conservative banks! If people are worried about their rent it is your duty to deny them the loan of one nickel, yes, even one copper engraving of the martyred son of the late Nancy Hanks; Yes, if they request fifty dollars to pay for a baby you must look at them like Tarzan looking at an uppity ape in the jungle, And tell them what do they think a bank is, anyhow, they had better go get the money from their wife''s aunt or ungle. But suppose people come in and they have a million and they want another million to pile on top of it, Why, you brim with the milk of human kindness and you urge them to accept every drop of it, And you lend them the million so then they have two million and this gives them the idea that they would be better off with four, So they already have two million as security so you have no hesitation in lending them two more, And all the vice-presidents nod their heads in rhythm, And the only question asked is do the borrowers want the money sent or do they want to take it withm. Because I think they deserve our appreciation and thanks, the jackasses who go around saying that health and happi- ness are everything and money isn''t essential, Because as soon as they have to borrow some unimportant money to maintain their health and happiness they starve to death so they can''t go around any more sneering at good old money, which is nothing short of providential. '   –we now turn it into XML declare @xml_data xml(WordList)  set @xml_data='<words>'+ replace(@string,'&', '&amp;')+'</words>'    select T.ref.value('.', 'nvarchar(100)')  from (Select @xml_data.query('                      for $i in data(/words) return                      element li { $i }               '))  A(list) cross apply A.List.nodes('/li') T(ref)     …which gives (truncated, of course)…

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• Survey: Your Plans for Adopting New Firefox Releases?

  - by Steven Chan (Oracle Development)

  Mozilla is committing to releasing new Firefox versions every six weeks.  Mozilla released Firefox 5 this week.  With this release, Mozilla states that Firefox 4 is End-of-Life and will not receive any additional security updates.  In a comment thread posted on to a Mike Kaply's blog article discussing these new Firefox policies, Asa Dotzler from Mozilla stated: ... Enterprise has never been (and I’ll argue, shouldn’t be) a focus of ours. Until we run out of people who don’t have sysadmins and enterprise deployment teams looking out for them, I can’t imagine why we’d focus at all on the kinds of environments you care so much about.  In a later comment, he added: ... A minute spent making a corporate user happy can better be spent making many regular users happy. I’d much rather Mozilla spending its limited resources looking out for the billions of users that don’t have enterprise support systems already taking care of them. Asa then confirmed that every new Firefox release will put the previous one into End-of-Life: As for John’s concern, “By the time I validate Firefox 5, what guarantee would I have that Firefox 5 won’t go EOL when Firefox 6 is released?” He has the opposite of guarantees that won’t happen. He has my promise that it will happen. Firefox 6 will be the EOL of Firefox 5. And Firefox 7 will be the EOL for Firefox 6.  He added: “You’re basically saying you don’t care about corporations.” Yes, I’m basically saying that I don’t care about making Firefox enterprise friendly. Kev Needham, Channel Manager at Mozilla later stated to PC Mag: The Web and Web browsers continue to evolve rapidly. Mozilla's focus is on providing users with the best Web experience possible, and Firefox needs to evolve at the pace the Web's users and developers expect. By releasing small, focused updates more often, we are able to deliver improved security and stability even as we introduce new features, which is better for our users, and for the Web.We recognize that this shift may not be compatible with a large organization's IT Policy and understand that it is challenging to organizations that have effort-intensive certification polices. However, our development process is geared toward delivering products that support the Web as it is today, while innovating and building future Web capabilities. Tying Firefox product development to an organizational process we do not control would make it difficult for us to continue to innovate for our users and the betterment of the Web.  Your feedback needed for E-Business Suite certifications  Mozilla's new support policy has significant implications for enterprise users of Firefox with Oracle E-Business Suite.  We are reviewing the implications for our certification and support policies for Firefox now.  It would be very helpful if you could let me know about your organisation's plans for Firefox in light of this new information.  Please feel free to drop me a private email, or post a comment here if that's appropriate. 

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• Access Control Service v2: Registering Web Identities in your Applications [concepts]

  - by Your DisplayName here!

  ACS v2 support two fundamental types of client identities– I like to call them “enterprise identities” (WS-*) and “web identities” (Google, LiveID, OpenId in general…). I also see two different “mind sets” when it comes to application design using the above identity types: Enterprise identities – often the fact that a client can present a token from a trusted identity provider means he is a legitimate user of the application. Trust relationships and authorization details have been negotiated out of band (often on paper). Web identities – the fact that a user can authenticate with Google et al does not necessarily mean he is a legitimate (or registered) user of an application. Typically additional steps are necessary (like filling out a form, email confirmation etc). Sometimes also a mixture of both approaches exist, for the sake of this post, I will focus on the web identity case. I got a number of questions how to implement the web identity scenario and after some conversations it turns out it is the old authentication vs. authorization problem that gets in the way. Many people use the IsAuthenticated property on IIdentity to make security decisions in their applications (or deny user=”?” in ASP.NET terms). That’s a very natural thing to do, because authentication was done inside the application and we knew exactly when the IsAuthenticated condition is true. Been there, done that. Guilty ;) The fundamental difference between these “old style” apps and federation is, that authentication is not done by the application anymore. It is done by a third party service, and in the case of web identity providers, in services that are not under our control (nor do we have a formal business relationship with these providers). Now the issue is, when you switch to ACS, and someone with a Google account authenticates, indeed IsAuthenticated is true – because that’s what he is! This does not mean, that he is also authorized to use the application. It just proves he was able to authenticate with Google. Now this obviously leads to confusion. How can we solve that? Easy answer: We have to deal with authentication and authorization separately. Job done ;) For many application types I see this general approach: Application uses ACS for authentication (maybe both enterprise and web identities, we focus on web identities but you could easily have a dual approach here) Application offers to authenticate (or sign in) via web identity accounts like LiveID, Google, Facebook etc. Application also maintains a database of its “own” users. Typically you want to store additional information about the user In such an application type it is important to have a unique identifier for your users (think the primary key of your user database). What would that be? Most web identity provider (and all the standard ACS v2 supported ones) emit a NameIdentifier claim. This is a stable ID for the client (scoped to the relying party – more on that later). Furthermore ACS emits a claims identifying the identity provider (like the original issuer concept in WIF). When you combine these two values together, you can be sure to have a unique identifier for the user, e.g.: Facebook-134952459903700\799880347 You can now check on incoming calls, if the user is already registered and if yes, swap the ACS claims with claims coming from your user database. One claims would maybe be a role like “Registered User” which can then be easily used to do authorization checks in the application. The WIF claims authentication manager is a perfect place to do the claims transformation. If the user is not registered, show a register form. Maybe you can use some claims from the identity provider to pre-fill form fields. (see here where I show how to use the Facebook API to fetch additional user properties). After successful registration (which may include other mechanisms like a confirmation email), flip the bit in your database to make the web identity a registered user. This is all very theoretical. In the next post I will show some code and provide a download link for the complete sample. More on NameIdentifier Identity providers “guarantee” that the name identifier for a given user in your application will always be the same. But different applications (in the case of ACS – different ACS namespaces) will see different name identifiers. This is by design to protect the privacy of users because identical name identifiers could be used to create “profiles” of some sort for that user. In technical terms they create the name identifier approximately like this: name identifier = Hash((Provider Internal User ID) + (Relying Party Address)) Why is this important to know? Well – when you change the name of your ACS namespace, the name identifiers will change as well and you will will lose your “connection” to your existing users. Oh an btw – never use any other claims (like email address or name) to form a unique ID – these can often be changed by users.

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• Think Before You Leap - Life is Dangerous for Change Agents

  - by technodrone

  So you want to introduce agile methods to your team... The following are some "lessons learned" when from someone who advocated agile/scrum to a group that was not ready for it. "Change agents, in my experience, face negative consequences. Sometimes, most of the time at the beginning, it's painful. This is the question you might have to ask yourself. Do you want to be a developer in scrum project or do you want be a scrum master managing the process? I think with proper mentoring/training, you can become good scrum master. But is that what you want? if yes, you can go ahead, take the training. if you want to be a developer, you may not need to be certified  as scrum master. You can just pick up from a book such as Mike Cohn new book Succeeding with Agile, I am reading it now. It's good. In my experience, I did waste my resources by trying to change the culture. It cost me lot. Instead, I should have focused on technical practices that are core to agile. Then look for teams that are good at agile. I would have saved lot of energy, and time. Try baby steps first yourself in the company, and next with the team, starting with technical practices like writing unit tests, SOLID principles, patterns, refactoring, continuous integration, pairing, and peer code reviews. These have inherent pull that can bring collaboration from a team.  Once you see team adaption in core practices, then you can introduce scrum concepts like user stories/task board etc.  This idea of Leading by example seems to be working for most of the agile folks. You can pitch core practices to the manager, and the team, and start showing them how you are doing.  You can put a road map for agile adaption and you can pitch to your manager. I would include need for scrum master training as part of the road map. " I thought about his advice for a couple of weeks and read about the pitfalls of technical debt and the team not having prior awareness of agile methods. The more I read and think about it the more I think he was right.  What do you think?

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• No drivers listed?/How to install all drivers? 12.10

  - by madmike59

  So i go to system settings in Ubuntu 12.10 and i want to install my drivers but under the Additional Drivers, My LAN doesnt work, Doesnt even pick up that im plugged in threw Ethernet cord. I have a GTX 670M with 3Gb GDDR5 for a video card and would like to use that. Just need help, pretty new to Ubuntu. Ok when i looked at that other question i did the sudo lspce -nn and this is what i got madmike@Mike-GT70:~$ sudo lspci -nn 00:00.0 Host bridge [0600]: Intel Corporation 3rd Gen Core processor DRAM Controller [8086:0154] (rev 09) 00:01.0 PCI bridge [0604]: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port [8086:0151] (rev 09) 00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) 00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [8086:1e31] (rev 04) 00:16.0 Communication controller [0780]: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 [8086:1e3a] (rev 04) 00:1a.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 [8086:1e2d] (rev 04) 00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller [8086:1e20] (rev 04) 00:1c.0 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 [8086:1e10] (rev c4) 00:1c.2 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 3 [8086:1e14] (rev c4) 00:1c.4 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 5 [8086:1e18] (rev c4) 00:1d.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 [8086:1e26] (rev 04) 00:1f.0 ISA bridge [0601]: Intel Corporation HM77 Express Chipset LPC Controller [8086:1e57] (rev 04) 00:1f.2 SATA controller [0106]: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] [8086:1e03] (rev 04) 00:1f.3 SMBus [0c05]: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller [8086:1e22] (rev 04) 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:1213] (rev ff) 02:00.0 Ethernet controller [0200]: Atheros Communications Inc. Device [1969:e091] (rev 13) 03:00.0 Network controller [0280]: Intel Corporation Centrino Wireless-N 2230 [8086:0887] (rev c4) 04:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader [10ec:5209] (rev 01) 04:00.1 SD Host controller [0805]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader [10ec:5209] (rev 01) Let me know if you need any more info? sorry it took so long.

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• What Counts for A DBA - Logic

  - by drsql

  "There are 10 kinds of people in the world. Those who will always wonder why there are only two items in my list and those who will figured it out the first time they saw this very old joke."  Those readers who will give up immediately and get frustrated with me for not explaining it to them are not likely going to be great technical professionals of any sort, much less a programmer or administrator who will be constantly dealing with the common failures that make up a DBA's day.  Many of these people will stare at this like a dog staring at a traffic signal and still have no more idea of how to decipher the riddle. Without explanation they will give up, call the joke "stupid" and, feeling quite superior, walk away indignantly to their job likely flipping patties of meat-by-product. As a data professional or any programmer who has strayed  to this very data-oriented blog, you would, if you are worth your weight in air, either have recognized immediately what was going on, or felt a bit ignorant.  Your friends are chuckling over the joke, but why is it funny? Unfortunately you left your smartphone at home on the dresser because you were up late last night programming and were running late to work (again), so you will either have to fake a laugh or figure it out.  Digging through the joke, you figure out that the word "two" is the most important part, since initially the joke mentioned 10. Hmm, why did they spell out two, but not ten? Maybe 10 could be interpreted a different way?  As a DBA, this sort of logic comes into play every day, and sometimes it doesn't involve nerdy riddles or Star Wars folklore.  When you turn on your computer and get the dreaded blue screen of death, you don't immediately cry to the help desk and sit on your thumbs and whine about not being able to work. Do that and your co-workers will question your nerd-hood; I know I certainly would. You figure out the problem, and when you have it narrowed down, you call the help desk and tell them what the problem is, usually having to explain that yes, you did in fact try to reboot before calling.  Of course, sometimes humility does come in to play when you reach the end of your abilities, but the ‘end of abilities’ is not something any of us recognize readily. It is handy to have the ability to use logic to solve uncommon problems: It becomes especially useful when you are trying to solve a data-related problem such as a query performance issue, and the way that you approach things will tell your coworkers a great deal about your abilities.  The novice is likely to immediately take the approach of  trying to add more indexes or blaming the hardware. As you become more and more experienced, it becomes increasingly obvious that performance issues are a very complex topic. A query may be slow for a myriad of reasons, from concurrency issues, a poor query plan because of a parameter value (like parameter sniffing,) poor coding standards, or just because it is a complex query that is going to be slow sometimes. Some queries that you will deal with may have twenty joins and hundreds of search criteria, and it can take a lot of thought to determine what is going on.  You can usually figure out the problem to almost any query by using basic knowledge of how joins and queries work, together with the help of such things as the query plan, profiler or monitoring tools.  It is not unlikely that it can take a full day’s work to understand some queries, breaking them down into smaller queries to find a very tiny problem. Not every time will you actually find the problem, and it is part of the process to occasionally admit that the problem is random, and everything works fine now.  Sometimes, it is necessary to realize that a problem is outside of your current knowledge, and admit temporary defeat: You can, at least, narrow down the source of the problem by looking logically at all of the possible solutions. By doing this, you can satisfy your curiosity and learn more about what the actual problem was. For example, in the joke, had you never been exposed to the concept of binary numbers, there is no way you could have known that binary - 10 = decimal - 2, but you could have logically come to the conclusion that 10 must not mean ten in the context of the joke, and at that point you are that much closer to getting the joke and at least won't feel so ignorant.

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• How to fix Ubuntu 12.04.3 boot to black screen full of errors in white text, after upgrading on dell inspiron 1501

  - by Ibuntu

  I am running a Dell Inspiron 1501 I use Linux only. No Microsoft or Apple operating systems (or really anything closed-source). I've only been using Linux for a little over a year but I'm starting to gain a comfortable level of familiarity with the system and terminology. I've been having some issues with Quantel Quetzal and Raring Ringtail, especially with older hardware, so I opted to install Ubuntu 12.04.3 Precise Pangolin on the Inspiron 1501. I checked my MD5 sum after downloading my ISO and all was good. I have in fact used this iso/dvd to install Precise Pangolin successfully on a few other systems (some of which are even older than this laptop). Install goes fine. The wireless card doesn't work out of the box but this is a known issue which is fairly easy to fix. So, first thing I did was open up a terminal and run sudo apt-get update && sudo apt-get upgrade which, part way through, crashed (I assume lightdm and possibly X) and took me to a black screen filled with white lines of text that were either errors or just the ouputs of commands. The reason I say that is because I was unable to gleam any useful information from the output on the screen. I did take a picture however and will post a link. After that, every time I boot the system it goes right to that black screen posting all the error messages or output in white text. I never get a purple Ubuntu splash, so from what I can tell after reading this wiki article: https://wiki.ubuntu.com/X/Troubleshooting/BlankScreen That means that after the kernel is selected, it is unable to correctly implement the settings it needs. If the purple splash never shows, the frame buffer was never set correctly right? This leads me to believe that it could be a kernel issue? The wiki suggested to try and pinpoint the issue by rolling back kernels until I find one that works. Is this my best option? I think I'm going to give it a try anyways and will let everyone know if I am able to solve the issue this way. I have since done a few reinstalls and some trouble-shooting including a couple hours scouring the net for anyone with any kind of similar issue. Most of the issues I could find involved getting a black screen after login and none of them said anything about any information output on this black screen. My reinstalls have taught me that there is no issue updating, but as soon as I run sudo apt-get upgrade my system goes to the black screen and every time I boot it up it does the same thing. The only way to fix is by reinstall. I never get any ability to log in. After a hard power off to the laptop (because I cannot use ctrl+alt+del to reboot) when it boots again it goes to the grub boot menu and I can select between regular boot, recovery mode and the two memtest options. I never tried the memtest options but the other two both lead to the same black screen. Some people having a black/blank screen issue claim to have fixed it by using 12.10 or 13.04 but I believe they were having a different issue where they got a black/blank screen after logging in. I think I will still give these images a try, but mostly figured I would just wait another day or two for 13.10. Other things I figured I would try from the following three articles: After logging in, there's a black screen and my cursor, nothing else! in Ubuntu 12.10 Black Screen on Login After Upgrading to 12.04 I can't get to the login screen include opening a terminal using ctrl+alt+f1 and trying a variety of reseting unity, x settings, lightdm (or switching to gdm); but I doubt this will work or that I will even be able to access a terminal. I'm pretty sure the whole system is stuck after it loads the last line on the black screen. I will try these things and post more information when I have. Hopefully someone has an idea in the meantime and I will keep checking back trying to find a solution. Thank you. Here are 3 different pictures of the error message. I had to take with my phone: http://ubuntuone.com/album/0TBBkxmVajJIQQtoN9mVdN

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• Answers to Conference Revenue Tweet Questions

  - by D'Arcy Lussier

  Originally posted on: http://geekswithblogs.net/dlussier/archive/2014/05/27/156612.aspxI tweeted this the other day… …and I had some people tweet back questioning/asking about the profit number. So here’s how I came to that figure. Total Revenue Let’s talk total revenue first. This conference has a huge list of companies/organizations paying some amount for sponsorship. Platinum ($1500) x 5 = $7500 Gold ($1000) x 3 = $3000 Silver ($500) x 9 = $4500 Bronze ($250) x 13 = $3250 There’s also a title sponsor level but there’s no mention of how much that is…more than $1500 though, so let’s just say $2500. Total Sponsorship Revenue: $20750.00 For registrations, this conference is claiming over 300 attendees. We’ll just calculate at 300 and the discounted “member rate” – $249. Total Registration Revenue: $74700.00 Booth space is also sold for a vendor area, but let’s just leave that out of the calculation. Total Event Revenue: $95450.00 Now that we know how much money we’re playing with, let’s knock out the costs for the event. Total Costs Hard Costs Audio/Visual Services $2000 Conference Rooms (4 Breakouts + Plenary) $2500 Insurance $700 Printing/Signage $1500 Travel/Hotel Rooms $2000 Keynotes $2000 So let’s talk about these hard costs first. First you may be asking about the Audio Visual. Yes those services can be that high, actually higher. But since there’s an A/V company touted as the official A/V provider, I gotta think there’s some discount for being branded as such. Conference rooms are actually an inflated amount of $500 per. Venues make money on the food they sell at events, not on room rentals. The more food, the cheaper the rooms tend to be offered at. Still, for the sake of argument, let’s set the rooms at $500 each knowing that they could be lower. For travel and hotel rooms…it appears that most of the speakers at this conference are local, meaning there’s no travel or hotel cost. But a few of them I wasn’t too sure…so let’s factor in enough to cover two outside speakers (airfare and hotel). There are two keynotes for this event and depending on the event those may be paid gigs. I’m not sure if they are or not, but considering the closing one is a comedian I’m going to add some funds here for that just in case. Total Hard Costs: $10700 Now that the hard costs are out of the way, let’s talk about the food costs. Food Costs The conference is providing a continental breakfast (YEEEESH!), some level of luncheon, and I have to assume coffee breaks in between. Let’s look at those costs. Continental Breakfast $12 per person Lunch Buffet $18 per person Coffee Breaks (2) $6 per person (or $3 a cup) Snacks (2) $10 per person (or $5 each) Note that the lunch buffet assumes a *good* lunch buffet – two entrees, starch, vegetable, salads, and bread. Not sure if there’ll be snacks during coffee breaks but let’s assume so. Total Food Cost Per Person: $46 Food Cost: $14950 Gratuity: $2691 Total Food Cost: $17641 Total food cost is based on the $46 per person cost x 325. 300 for attendance, 12 for speakers, extra 13 for volunteers/organizers. Gratuity is 18%. Grand Totals So let’s sum things up here. Total Costs Hard Costs: $10700.00 Food Costs: $17641.00 Total:          $28341.00 Taxes:         $3685.00 Grand Total  $32026.00 Total Revenue Sponsorship  $20750 Registration   $74700 Grand Total   $95450.00 Total Profit $63424.00 Now what if the registration numbers were lower and they only got 100 people to show up. In that scenario there’d still be a profit of just under $26000. Closing Comments A couple of things to note: - I haven’t factored in anything for prizes. Not sure if any will be given out - We didn’t add in the booth space revenue - We’re assuming speakers aren’t getting paid, but even if they were at the high end its $12000 ($1000 per session), which is probably an inflated number for local speakers. - Note that all registrations were set to the “member” discounted price. The non-member registration price is higher. There is also an option for those that just want to show up for the opening keynote. There you have it! Let me know if you have any questions. D

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• How to move a rectangle properly?

  - by bodycountPP

  I recently started to learn OpenGL. Right now I finished the first chapter of the "OpenGL SuperBible". There were two examples. The first had the complete code and showed how to draw a simple triangle. The second example is supposed to show how to move a rectangle using SpecialKeys. The only code provided for this example was the SpecialKeys method. I still tried to implement it but I had two problems. In the previous example I declared and instaciated vVerts in the SetupRC() method. Now as it is also used in the SpecialKeys() method, I moved the declaration and instantiation to the top of the code. Is this proper c++ practice? I copied the part where vertex positions are recalculated from the book, but I had to pick the vertices for the rectangle on my own. So now every time I press a key for the first time the rectangle's upper left vertex is moved to (-0,5:-0.5). This ok because of GLfloat blockX = vVerts[0]; //Upper left X GLfloat blockY = vVerts[7]; // Upper left Y But I also think that this is the reason why my rectangle is shifted in the beginning. After the first time a key was pressed everything works just fine. Here is my complete code I hope you can help me on those two points. GLBatch squareBatch; GLShaderManager shaderManager; //Load up a triangle GLfloat vVerts[] = {-0.5f,0.5f,0.0f, 0.5f,0.5f,0.0f, 0.5f,-0.5f,0.0f, -0.5f,-0.5f,0.0f}; //Window has changed size, or has just been created. //We need to use the window dimensions to set the viewport and the projection matrix. void ChangeSize(int w, int h) { glViewport(0,0,w,h); } //Called to draw the scene. void RenderScene(void) { //Clear the window with the current clearing color glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT); GLfloat vRed[] = {1.0f,0.0f,0.0f,1.0f}; shaderManager.UseStockShader(GLT_SHADER_IDENTITY,vRed); squareBatch.Draw(); //perform the buffer swap to display the back buffer glutSwapBuffers(); } //This function does any needed initialization on the rendering context. //This is the first opportunity to do any OpenGL related Tasks. void SetupRC() { //Blue Background glClearColor(0.0f,0.0f,1.0f,1.0f); shaderManager.InitializeStockShaders(); squareBatch.Begin(GL_QUADS,4); squareBatch.CopyVertexData3f(vVerts); squareBatch.End(); } //Respond to arrow keys by moving the camera frame of reference void SpecialKeys(int key,int x,int y) { GLfloat stepSize = 0.025f; GLfloat blockSize = 0.5f; GLfloat blockX = vVerts[0]; //Upper left X GLfloat blockY = vVerts[7]; // Upper left Y if(key == GLUT_KEY_UP) { blockY += stepSize; } if(key == GLUT_KEY_DOWN){blockY -= stepSize;} if(key == GLUT_KEY_LEFT){blockX -= stepSize;} if(key == GLUT_KEY_RIGHT){blockX += stepSize;} //Recalculate vertex positions vVerts[0] = blockX; vVerts[1] = blockY - blockSize*2; vVerts[3] = blockX + blockSize * 2; vVerts[4] = blockY - blockSize *2; vVerts[6] = blockX+blockSize*2; vVerts[7] = blockY; vVerts[9] = blockX; vVerts[10] = blockY; squareBatch.CopyVertexData3f(vVerts); glutPostRedisplay(); } //Main entry point for GLUT based programs int main(int argc, char** argv) { //Sets the working directory. Not really needed gltSetWorkingDirectory(argv[0]); //Passes along the command-line parameters and initializes the GLUT library. glutInit(&argc,argv); //Tells the GLUT library what type of display mode to use, when creating the window. //Double buffered window, RGBA-Color mode,depth-buffer as part of our display, stencil buffer also available glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL); //Window size glutInitWindowSize(800,600); glutCreateWindow("MoveRect"); glutReshapeFunc(ChangeSize); glutDisplayFunc(RenderScene); glutSpecialFunc(SpecialKeys); //initialize GLEW library GLenum err = glewInit(); //Check that nothing goes wrong with the driver initialization before we try and do any rendering. if(GLEW_OK != err) { fprintf(stderr,"Glew Error: %s\n",glewGetErrorString); return 1; } SetupRC(); glutMainLoop(); return 0; }

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• The Dreaded Startup Repair Loop on Win 7

  - by HighAltitudeCoder

  For most people, upgrading to Windows 7 has been a relatively painless process.  Not me.  I am in the unlucky 1% or less who had a somewhat less pleasant experience.  First, I cloned my entire onto a larger (and much faster) solid state hard drive, only experiencing minimal problems. Then, I bought the Retail version of Windows 7 Ultimate, took a deep breath and... oh yeah, I almost forgot - BACK UP THE COMPUTER.  The next morning I upgraded to Win 7 and everything seemed fine, until... I rebooted the system, the nice Windows 7 launch graphics come up, it's about to launch and AWWW, are you kidding me?!?!  Back to the BIOS splash screen?  Next comes the sequence of failure - attempt repair - unable to repair - do you want to wipe your hard drive decisions. Because I purchased the retail version, a number is provided where I could call Microsoft Tech support.  When I did, they instructed me to click "Install" from my installation CD, which did not work.  When I tried the "Upgrade" option, it reaches an impasse, telling you that yoiu have a newer version of Win 7, and thus cannot Upgrade.  If you choose "Install" you willl lose everything... files, programs, EVERYTHING.  Or at least this is what it tells you.  I was not willing to take the risk. To make things worse, I had installed a new antivirus software application before I realized my system was unstable (Trend Micro Titanium Internet Security), and this was causing additional problems. One interesting thing, and the only saving grace as it turns out, was that my system WOULD successfully reboot into the OS if I chose to restart it, rather than shut it down.  If I chose to shut down, I would have to go through the loop again until I was given the option to restart. As it turned out, I needed to update my BIOS.  I assumed that since I had updated my BIOS a long time ago to settings that were stable under Windows Vista Ultimate x64, I incorrectly expected Win 7 to adopt the same settings and didn't expect there to be any problems.  WRONG. My BIOS had a setting to halt the boot cycle if various kinds of errors were detected.  Windows Vista didn't care about this, but forget it under Windows 7.  I turned immediately corrected that BIOS setting.  Next, there were the two separate BIOS settings: enable USB mouse and enable USB keyboard.  The only sequence of events that would work were to start my reboot process over from stratch with a hard-wired non-usb keyboard and mouse.  Whent the system booted under these settings, it doesn't detect any errors due to either the mouse or keyboard, and actually booted for the first time in a long while (let me tell ya, that's an amazing experience after fiddling with settings for two entire weekends!) Next step: leave your old mouse and keyboard connected, but also connect your other two devices (mouse, keyboard) that use USB connections.  During the boot cycle, the operating system will not fail due to missing requirements during startup, and it will then pick up the new drivers necessary to use your new hardware. If you think you are in the clear here, you are wrong.  The next VERY IMPORTANT step is to remember to change your settings in the BIOS upon next startup.  Specifically, yoiu will need ot change your BIOS to enable USB mouse and enable USB keyboard input.  If you don't, Windows will detect an incompatibility upon the next startup, and you will be stuck once again in the endless cycle of reboot/Startup Repair/reboot/Startup Repair, without ever reaching a successful boot. Here's the thing - the BIOS and the drivers registered in Win 7 need to match.  If they don't, you're going to lose another weekend worrying and fiddling, all the while wondering if you've permanently damaged your hard drive beyond repair. (Sigh).  In the end, things worked out.  I must note that it is saddening to see how many posts there are out there that recommend just doing a clean install, as if it's the only option.  How many countless poor souls have lost their data, their backups, their pictures and videos, all for nothing other than the fact that the person giving advice just didn't know what to do at that point? My advice to you, try having a look at your BIOS settings first and making sure Win 7 can find your BIOS settings, and also disabling in your BIOS anything that might halt your system boot-up process if it encounters errors.

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• The Execute SQL Task

  In this article we are going to take you through the Execute SQL Task in SQL Server Integration Services for SQL Server 2005 (although it appies just as well to SQL Server 2008).  We will be covering all the essentials that you will need to know to effectively use this task and make it as flexible as possible. The things we will be looking at are as follows: A tour of the Task. The properties of the Task. After looking at these introductory topics we will then get into some examples. The examples will show different types of usage for the task: Returning a single value from a SQL query with two input parameters. Returning a rowset from a SQL query. Executing a stored procedure and retrieveing a rowset, a return value, an output parameter value and passing in an input parameter. Passing in the SQL Statement from a variable. Passing in the SQL Statement from a file. Tour Of The Task Before we can start to use the Execute SQL Task in our packages we are going to need to locate it in the toolbox. Let's do that now. Whilst in the Control Flow section of the package expand your toolbox and locate the Execute SQL Task. Below is how we found ours. Now drag the task onto the designer. As you can see from the following image we have a validation error appear telling us that no connection manager has been assigned to the task. This can be easily remedied by creating a connection manager. There are certain types of connection manager that are compatable with this task so we cannot just create any connection manager and these are detailed in a few graphics time. Double click on the task itself to take a look at the custom user interface provided to us for this task. The task will open on the general tab as shown below. Take a bit of time to have a look around here as throughout this article we will be revisting this page many times. Whilst on the general tab, drop down the combobox next to the ConnectionType property. In here you will see the types of connection manager which this task will accept. As with SQL Server 2000 DTS, SSIS allows you to output values from this task in a number of formats. Have a look at the combobox next to the Resultset property. The major difference here is the ability to output into XML. If you drop down the combobox next to the SQLSourceType property you will see the ways in which you can pass a SQL Statement into the task itself. We will have examples of each of these later on but certainly when we saw these for the first time we were very excited. Next to the SQLStatement property if you click in the empty box next to it you will see ellipses appear. Click on them and you will see the very basic query editor that becomes available to you. Alternatively after you have specified a connection manager for the task you can click on the Build Query button to bring up a completely different query editor. This is slightly inconsistent. Once you've finished looking around the general tab, move on to the next tab which is the parameter mapping tab. We shall, again, be visiting this tab throughout the article but to give you an initial heads up this is where you define the input, output and return values from your task. Note this is not where you specify the resultset. If however you now move on to the ResultSet tab this is where you define what variable will receive the output from your SQL Statement in whatever form that is. Property Expressions are one of the most amazing things to happen in SSIS and they will not be covered here as they deserve a whole article to themselves. Watch out for this as their usefulness will astound you. For a more detailed discussion of what should be the parameter markers in the SQL Statements on the General tab and how to map them to variables on the Parameter Mapping tab see Working with Parameters and Return Codes in the Execute SQL Task. Task Properties There are two places where you can specify the properties for your task. One is in the task UI itself and the other is in the property pane which will appear if you right click on your task and select Properties from the context menu. We will be doing plenty of property setting in the UI later so let's take a moment to have a look at the property pane. Below is a graphic showing our properties pane. Now we shall take you through all the properties and tell you exactly what they mean. A lot of these properties you will see across all tasks as well as the package because of everything's base structure The Container. BypassPrepare Should the statement be prepared before sending to the connection manager destination (True/False) Connection This is simply the name of the connection manager that the task will use. We can get this from the connection manager tray at the bottom of the package. DelayValidation Really interesting property and it tells the task to not validate until it actually executes. A usage for this may be that you are operating on table yet to be created but at runtime you know the table will be there. Description Very simply the description of your Task. Disable Should the task be enabled or not? You can also set this through a context menu by right clicking on the task itself. DisableEventHandlers As a result of events that happen in the task, should the event handlers for the container fire? ExecValueVariable The variable assigned here will get or set the execution value of the task. Expressions Expressions as we mentioned earlier are a really powerful tool in SSIS and this graphic below shows us a small peek of what you can do. We select a property on the left and assign an expression to the value of that property on the right causing the value to be dynamically changed at runtime. One of the most obvious uses of this is that the property value can be built dynamically from within the package allowing you a great deal of flexibility FailPackageOnFailure If this task fails does the package? FailParentOnFailure If this task fails does the parent container? A task can he hosted inside another container i.e. the For Each Loop Container and this would then be the parent. ForcedExecutionValue This property allows you to hard code an execution value for the task. ForcedExecutionValueType What is the datatype of the ForcedExecutionValue? ForceExecutionResult Force the task to return a certain execution result. This could then be used by the workflow constraints. Possible values are None, Success, Failure and Completion. ForceExecutionValue Should we force the execution result? IsolationLevel This is the transaction isolation level of the task. IsStoredProcedure Certain optimisations are made by the task if it knows that the query is a Stored Procedure invocation. The docs say this will always be false unless the connection is an ADO connection. LocaleID Gets or sets the LocaleID of the container. LoggingMode Should we log for this container and what settings should we use? The value choices are UseParentSetting, Enabled and Disabled. MaximumErrorCount How many times can the task fail before we call it a day? Name Very simply the name of the task. ResultSetType How do you want the results of your query returned? The choices are ResultSetType_None, ResultSetType_SingleRow, ResultSetType_Rowset and ResultSetType_XML. SqlStatementSource Your Query/SQL Statement. SqlStatementSourceType The method of specifying the query. Your choices here are DirectInput, FileConnection and Variables TimeOut How long should the task wait to receive results? TransactionOption How should the task handle being asked to join a transaction? Usage Examples As we move through the examples we will only cover in them what we think you must know and what we think you should see. This means that some of the more elementary steps like setting up variables will be covered in the early examples but skipped and simply referred to in later ones. All these examples used the AventureWorks database that comes with SQL Server 2005. Returning a Single Value, Passing in Two Input Parameters So the first thing we are going to do is add some variables to our package. The graphic below shows us those variables having been defined. Here the CountOfEmployees variable will be used as the output from the query and EndDate and StartDate will be used as input parameters. As you can see all these variables have been scoped to the package. Scoping allows us to have domains for variables. Each container has a scope and remember a package is a container as well. Variable values of the parent container can be seen in child containers but cannot be passed back up to the parent from a child. Our following graphic has had a number of changes made. The first of those changes is that we have created and assigned an OLEDB connection manager to this Task ExecuteSQL Task Connection. The next thing is we have made sure that the SQLSourceType property is set to Direct Input as we will be writing in our statement ourselves. We have also specified that only a single row will be returned from this query. The expressions we typed in was: SELECT COUNT(*) AS CountOfEmployees FROM HumanResources.Employee WHERE (HireDate BETWEEN ? AND ?) Moving on now to the Parameter Mapping tab this is where we are going to tell the task about our input paramaters. We Add them to the window specifying their direction and datatype. A quick word here about the structure of the variable name. As you can see SSIS has preceeded the variable with the word user. This is a default namespace for variables but you can create your own. When defining your variables if you look at the variables window title bar you will see some icons. If you hover over the last one on the right you will see it says "Choose Variable Columns". If you click the button you will see a list of checkbox options and one of them is namespace. after checking this you will see now where you can define your own namespace. The next tab, result set, is where we need to get back the value(s) returned from our statement and assign to a variable which in our case is CountOfEmployees so we can use it later perhaps. Because we are only returning a single value then if you remember from earlier we are allowed to assign a name to the resultset but it must be the name of the column (or alias) from the query. A really cool feature of Business Intelligence Studio being hosted by Visual Studio is that we get breakpoint support for free. In our package we set a Breakpoint so we can break the package and have a look in a watch window at the variable values as they appear to our task and what the variable value of our resultset is after the task has done the assignment. Here's that window now. As you can see the count of employess that matched the data range was 2. Returning a Rowset In this example we are going to return a resultset back to a variable after the task has executed not just a single row single value. There are no input parameters required so the variables window is nice and straight forward. One variable of type object. Here is the statement that will form the soure for our Resultset. select p.ProductNumber, p.name, pc.Name as ProductCategoryNameFROM Production.ProductCategory pcJOIN Production.ProductSubCategory pscON pc.ProductCategoryID = psc.ProductCategoryIDJOIN Production.Product pON psc.ProductSubCategoryID = p.ProductSubCategoryID We need to make sure that we have selected Full result set as the ResultSet as shown below on the task's General tab. Because there are no input parameters we can skip the parameter mapping tab and move straight to the Result Set tab. Here we need to Add our variable defined earlier and map it to the result name of 0 (remember we covered this earlier) Once we run the task we can again set a breakpoint and have a look at the values coming back from the task. In the following graphic you can see the result set returned to us as a COM object. We can do some pretty interesting things with this COM object and in later articles that is exactly what we shall be doing. Return Values, Input/Output Parameters and Returning a Rowset from a Stored Procedure This example is pretty much going to give us a taste of everything. We have already covered in the previous example how to specify the ResultSet to be a Full result set so we will not cover it again here. For this example we are going to need 4 variables. One for the return value, one for the input parameter, one for the output parameter and one for the result set. Here is the statement we want to execute. Note how much cleaner it is than if you wanted to do it using the current version of DTS. In the Parameter Mapping tab we are going to Add our variables and specify their direction and datatypes. In the Result Set tab we can now map our final variable to the rowset returned from the stored procedure. It really is as simple as that and we were amazed at how much easier it is than in DTS 2000. Passing in the SQL Statement from a Variable SSIS as we have mentioned is hugely more flexible than its predecessor and one of the things you will notice when moving around the tasks and the adapters is that a lot of them accept a variable as an input for something they need. The ExecuteSQL task is no different. It will allow us to pass in a string variable as the SQL Statement. This variable value could have been set earlier on from inside the package or it could have been populated from outside using a configuration. The ResultSet property is set to single row and we'll show you why in a second when we look at the variables. Note also the SQLSourceType property. Here's the General Tab again. Looking at the variable we have in this package you can see we have only two. One for the return value from the statement and one which is obviously for the statement itself. Again we need to map the Result name to our variable and this can be a named Result Name (The column name or alias returned by the query) and not 0. The expected result into our variable should be the amount of rows in the Person.Contact table and if we look in the watch window we see that it is.   Passing in the SQL Statement from a File The final example we are going to show is a really interesting one. We are going to pass in the SQL statement to the task by using a file connection manager. The file itself contains the statement to run. The first thing we are going to need to do is create our file connection mananger to point to our file. Click in the connections tray at the bottom of the designer, right click and choose "New File Connection" As you can see in the graphic below we have chosen to use an existing file and have passed in the name as well. Have a look around at the other "Usage Type" values available whilst you are here. Having set that up we can now see in the connection manager tray our file connection manager sitting alongside our OLE-DB connection we have been using for the rest of these examples. Now we can go back to the familiar General Tab to set up how the task will accept our file connection as the source. All the other properties in this task are set up exactly as we have been doing for other examples depending on the options chosen so we will not cover them again here.   We hope you will agree that the Execute SQL Task has changed considerably in this release from its DTS predecessor. It has a lot of options available but once you have configured it a few times you get to learn what needs to go where. We hope you have found this article useful.

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• Working with PivotTables in Excel

  - by Mark Virtue

  PivotTables are one of the most powerful features of Microsoft Excel.  They allow large amounts of data to be analyzed and summarized in just a few mouse clicks. In this article, we explore PivotTables, understand what they are, and learn how to create and customize them. Note:  This article is written using Excel 2010 (Beta).  The concept of a PivotTable has changed little over the years, but the method of creating one has changed in nearly every iteration of Excel.  If you are using a version of Excel that is not 2010, expect different screens from the ones you see in this article. A Little History In the early days of spreadsheet programs, Lotus 1-2-3 ruled the roost.  Its dominance was so complete that people thought it was a waste of time for Microsoft to bother developing their own spreadsheet software (Excel) to compete with Lotus.  Flash-forward to 2010, and Excel’s dominance of the spreadsheet market is greater than Lotus’s ever was, while the number of users still running Lotus 1-2-3 is approaching zero.  How did this happen?  What caused such a dramatic reversal of fortunes? Industry analysts put it down to two factors:  Firstly, Lotus decided that this fancy new GUI platform called “Windows” was a passing fad that would never take off.  They declined to create a Windows version of Lotus 1-2-3 (for a few years, anyway), predicting that their DOS version of the software was all anyone would ever need.  Microsoft, naturally, developed Excel exclusively for Windows.  Secondly, Microsoft developed a feature for Excel that Lotus didn’t provide in 1-2-3, namely PivotTables.  The PivotTables feature, exclusive to Excel, was deemed so staggeringly useful that people were willing to learn an entire new software package (Excel) rather than stick with a program (1-2-3) that didn’t have it.  This one feature, along with the misjudgment of the success of Windows, was the death-knell for Lotus 1-2-3, and the beginning of the success of Microsoft Excel. Understanding PivotTables So what is a PivotTable, exactly? Put simply, a PivotTable is a summary of some data, created to allow easy analysis of said data.  But unlike a manually created summary, Excel PivotTables are interactive.  Once you have created one, you can easily change it if it doesn’t offer the exact insights into your data that you were hoping for.  In a couple of clicks the summary can be “pivoted” – rotated in such a way that the column headings become row headings, and vice versa.  There’s a lot more that can be done, too.  Rather than try to describe all the features of PivotTables, we’ll simply demonstrate them… The data that you analyze using a PivotTable can’t be just any data – it has to be raw data, previously unprocessed (unsummarized) – typically a list of some sort.  An example of this might be the list of sales transactions in a company for the past six months. Examine the data shown below: Notice that this is not raw data.  In fact, it is already a summary of some sort.  In cell B3 we can see $30,000, which apparently is the total of James Cook’s sales for the month of January.  So where is the raw data?  How did we arrive at the figure of $30,000?  Where is the original list of sales transactions that this figure was generated from?  It’s clear that somewhere, someone must have gone to the trouble of collating all of the sales transactions for the past six months into the summary we see above.  How long do you suppose this took?  An hour?  Ten?  Probably. If we were to track down the original list of sales transactions, it might look something like this: You may be surprised to learn that, using the PivotTable feature of Excel, we can create a monthly sales summary similar to the one above in a few seconds, with only a few mouse clicks.  We can do this – and a lot more too! How to Create a PivotTable First, ensure that you have some raw data in a worksheet in Excel.  A list of financial transactions is typical, but it can be a list of just about anything:  Employee contact details, your CD collection, or fuel consumption figures for your company’s fleet of cars. So we start Excel… …and we load such a list… Once we have the list open in Excel, we’re ready to start creating the PivotTable. Click on any one single cell within the list: Then, from the Insert tab, click the PivotTable icon: The Create PivotTable box appears, asking you two questions:  What data should your new PivotTable be based on, and where should it be created?  Because we already clicked on a cell within the list (in the step above), the entire list surrounding that cell is already selected for us ($A$1:$G$88 on the Payments sheet, in this example).  Note that we could select a list in any other region of any other worksheet, or even some external data source, such as an Access database table, or even a MS-SQL Server database table.  We also need to select whether we want our new PivotTable to be created on a new worksheet, or on an existing one.  In this example we will select a new one: The new worksheet is created for us, and a blank PivotTable is created on that worksheet: Another box also appears:  The PivotTable Field List.  This field list will be shown whenever we click on any cell within the PivotTable (above): The list of fields in the top part of the box is actually the collection of column headings from the original raw data worksheet.  The four blank boxes in the lower part of the screen allow us to choose the way we would like our PivotTable to summarize the raw data.  So far, there is nothing in those boxes, so the PivotTable is blank.  All we need to do is drag fields down from the list above and drop them in the lower boxes.  A PivotTable is then automatically created to match our instructions.  If we get it wrong, we only need to drag the fields back to where they came from and/or drag new fields down to replace them. The Values box is arguably the most important of the four.  The field that is dragged into this box represents the data that needs to be summarized in some way (by summing, averaging, finding the maximum, minimum, etc).  It is almost always numerical data.  A perfect candidate for this box in our sample data is the “Amount” field/column.  Let’s drag that field into the Values box: Notice that (a) the “Amount” field in the list of fields is now ticked, and “Sum of Amount” has been added to the Values box, indicating that the amount column has been summed. If we examine the PivotTable itself, we indeed find the sum of all the “Amount” values from the raw data worksheet: We’ve created our first PivotTable!  Handy, but not particularly impressive.  It’s likely that we need a little more insight into our data than that. Referring to our sample data, we need to identify one or more column headings that we could conceivably use to split this total.  For example, we may decide that we would like to see a summary of our data where we have a row heading for each of the different salespersons in our company, and a total for each.  To achieve this, all we need to do is to drag the “Salesperson” field into the Row Labels box: Now, finally, things start to get interesting!  Our PivotTable starts to take shape….   With a couple of clicks we have created a table that would have taken a long time to do manually. So what else can we do?  Well, in one sense our PivotTable is complete.  We’ve created a useful summary of our source data.  The important stuff is already learned!  For the rest of the article, we will examine some ways that more complex PivotTables can be created, and ways that those PivotTables can be customized. First, we can create a two-dimensional table.  Let’s do that by using “Payment Method” as a column heading.  Simply drag the “Payment Method” heading to the Column Labels box: Which looks like this: Starting to get very cool! Let’s make it a three-dimensional table.  What could such a table possibly look like?  Well, let’s see… Drag the “Package” column/heading to the Report Filter box: Notice where it ends up…. This allows us to filter our report based on which “holiday package” was being purchased.  For example, we can see the breakdown of salesperson vs payment method for all packages, or, with a couple of clicks, change it to show the same breakdown for the “Sunseekers” package: And so, if you think about it the right way, our PivotTable is now three-dimensional.  Let’s keep customizing… If it turns out, say, that we only want to see cheque and credit card transactions (i.e. no cash transactions), then we can deselect the “Cash” item from the column headings.  Click the drop-down arrow next to Column Labels, and untick “Cash”: Let’s see what that looks like…As you can see, “Cash” is gone. Formatting This is obviously a very powerful system, but so far the results look very plain and boring.  For a start, the numbers that we’re summing do not look like dollar amounts – just plain old numbers.  Let’s rectify that. A temptation might be to do what we’re used to doing in such circumstances and simply select the whole table (or the whole worksheet) and use the standard number formatting buttons on the toolbar to complete the formatting.  The problem with that approach is that if you ever change the structure of the PivotTable in the future (which is 99% likely), then those number formats will be lost.  We need a way that will make them (semi-)permanent. First, we locate the “Sum of Amount” entry in the Values box, and click on it.  A menu appears.  We select Value Field Settings… from the menu: The Value Field Settings box appears. Click the Number Format button, and the standard Format Cells box appears: From the Category list, select (say) Accounting, and drop the number of decimal places to 0.  Click OK a few times to get back to the PivotTable… As you can see, the numbers have been correctly formatted as dollar amounts. While we’re on the subject of formatting, let’s format the entire PivotTable.  There are a few ways to do this.  Let’s use a simple one… Click the PivotTable Tools/Design tab: Then drop down the arrow in the bottom-right of the PivotTable Styles list to see a vast collection of built-in styles: Choose any one that appeals, and look at the result in your PivotTable:   Other Options We can work with dates as well.  Now usually, there are many, many dates in a transaction list such as the one we started with.  But Excel provides the option to group data items together by day, week, month, year, etc.  Let’s see how this is done. First, let’s remove the “Payment Method” column from the Column Labels box (simply drag it back up to the field list), and replace it with the “Date Booked” column: As you can see, this makes our PivotTable instantly useless, giving us one column for each date that a transaction occurred on – a very wide table! To fix this, right-click on any date and select Group… from the context-menu: The grouping box appears.  We select Months and click OK: Voila!  A much more useful table: (Incidentally, this table is virtually identical to the one shown at the beginning of this article – the original sales summary that was created manually.) Another cool thing to be aware of is that you can have more than one set of row headings (or column headings): …which looks like this…. You can do a similar thing with column headings (or even report filters). Keeping things simple again, let’s see how to plot averaged values, rather than summed values. First, click on “Sum of Amount”, and select Value Field Settings… from the context-menu that appears: In the Summarize value field by list in the Value Field Settings box, select Average: While we’re here, let’s change the Custom Name, from “Average of Amount” to something a little more concise.  Type in something like “Avg”: Click OK, and see what it looks like.  Notice that all the values change from summed totals to averages, and the table title (top-left cell) has changed to “Avg”: If we like, we can even have sums, averages and counts (counts = how many sales there were) all on the same PivotTable! Here are the steps to get something like that in place (starting from a blank PivotTable): Drag “Salesperson” into the Column Labels Drag “Amount” field down into the Values box three times For the first “Amount” field, change its custom name to “Total” and it’s number format to Accounting (0 decimal places) For the second “Amount” field, change its custom name to “Average”, its function to Average and it’s number format to Accounting (0 decimal places) For the third “Amount” field, change its name to “Count” and its function to Count Drag the automatically created field from Column Labels to Row Labels Here’s what we end up with: Total, average and count on the same PivotTable! Conclusion There are many, many more features and options for PivotTables created by Microsoft Excel – far too many to list in an article like this.  To fully cover the potential of PivotTables, a small book (or a large website) would be required.  Brave and/or geeky readers can explore PivotTables further quite easily:  Simply right-click on just about everything, and see what options become available to you.  There are also the two ribbon-tabs: PivotTable Tools/Options and Design.  It doesn’t matter if you make a mistake – it’s easy to delete the PivotTable and start again – a possibility old DOS users of Lotus 1-2-3 never had. We’ve included an Excel that should work with most versions of Excel, so you can download to practice your PivotTable skills. Download Our Practice Excel File Similar Articles Productive Geek Tips Magnify Selected Cells In Excel 2007Share Access Data with Excel in Office 2010Make Excel 2007 Print Gridlines In Workbook FileMake Excel 2007 Always Save in Excel 2003 FormatConvert Older Excel Documents to Excel 2007 Format TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Ben & Jerry’s Free Cone Day, 3/23/10 New Stinger from McAfee Helps Remove ‘FakeAlert’ Threats Google Apps Marketplace: Tools & Services For Google Apps Users Get News Quick and Precise With Newser Scan for Viruses in Ubuntu using ClamAV Replace Your Windows Task Manager With System Explorer

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• Passing multiple POST parameters to Web API Controller Methods

  - by Rick Strahl

  ASP.NET Web API introduces a new API for creating REST APIs and making AJAX callbacks to the server. This new API provides a host of new great functionality that unifies many of the features of many of the various AJAX/REST APIs that Microsoft created before it - ASP.NET AJAX, WCF REST specifically - and combines them into a whole more consistent API. Web API addresses many of the concerns that developers had with these older APIs, namely that it was very difficult to build consistent REST style resource APIs easily. While Web API provides many new features and makes many scenarios much easier, a lot of the focus has been on making it easier to build REST compliant APIs that are focused on resource based solutions and HTTP verbs. But  RPC style calls that are common with AJAX callbacks in Web applications, have gotten a lot less focus and there are a few scenarios that are not that obvious, especially if you're expecting Web API to provide functionality similar to ASP.NET AJAX style AJAX callbacks. RPC vs. 'Proper' REST RPC style HTTP calls mimic calling a method with parameters and returning a result. Rather than mapping explicit server side resources or 'nouns' RPC calls tend simply map a server side operation, passing in parameters and receiving a typed result where parameters and result values are marshaled over HTTP. Typically RPC calls - like SOAP calls - tend to always be POST operations rather than following HTTP conventions and using the GET/POST/PUT/DELETE etc. verbs to implicitly determine what operation needs to be fired. RPC might not be considered 'cool' anymore, but for typical private AJAX backend operations of a Web site I'd wager that a large percentage of use cases of Web API will fall towards RPC style calls rather than 'proper' REST style APIs. Web applications that have needs for things like live validation against data, filling data based on user inputs, handling small UI updates often don't lend themselves very well to limited HTTP verb usage. It might not be what the cool kids do, but I don't see RPC calls getting replaced by proper REST APIs any time soon.  Proper REST has its place - for 'real' API scenarios that manage and publish/share resources, but for more transactional operations RPC seems a better choice and much easier to implement than trying to shoehorn a boatload of endpoint methods into a few HTTP verbs. In any case Web API does a good job of providing both RPC abstraction as well as the HTTP Verb/REST abstraction. RPC works well out of the box, but there are some differences especially if you're coming from ASP.NET AJAX service or WCF Rest when it comes to multiple parameters. Action Routing for RPC Style Calls If you've looked at Web API demos you've probably seen a bunch of examples of how to create HTTP Verb based routing endpoints. Verb based routing essentially maps a controller and then uses HTTP verbs to map the methods that are called in response to HTTP requests. This works great for resource APIs but doesn't work so well when you have many operational methods in a single controller. HTTP Verb routing is limited to the few HTTP verbs available (plus separate method signatures) and - worse than that - you can't easily extend the controller with custom routes or action routing beyond that. Thankfully Web API also supports Action based routing which allows you create RPC style endpoints fairly easily:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumApi", action = "GetAblums" } ); This uses traditional MVC style {action} method routing which is different from the HTTP verb based routing you might have read a bunch about in conjunction with Web API. Action based routing like above lets you specify an end point method in a Web API controller either via the {action} parameter in the route string or via a default value for custom routes. Using routing you can pass multiple parameters either on the route itself or pass parameters on the query string, via ModelBinding or content value binding. For most common scenarios this actually works very well. As long as you are passing either a single complex type via a POST operation, or multiple simple types via query string or POST buffer, there's no issue. But if you need to pass multiple parameters as was easily done with WCF REST or ASP.NET AJAX things are not so obvious. Web API has no issue allowing for single parameter like this:[HttpPost] public string PostAlbum(Album album) { return String.Format("{0} {1:d}", album.AlbumName, album.Entered); } There are actually two ways to call this endpoint: albums/PostAlbum Using the Model Binder with plain POST values In this mechanism you're sending plain urlencoded POST values to the server which the ModelBinder then maps the parameter. Each property value is matched to each matching POST value. This works similar to the way that MVC's  ModelBinder works. Here's how you can POST using the ModelBinder and jQuery:$.ajax( { url: "albums/PostAlbum", type: "POST", data: { AlbumName: "Dirty Deeds", Entered: "5/1/2012" }, success: function (result) { alert(result); }, error: function (xhr, status, p3, p4) { var err = "Error " + " " + status + " " + p3; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); Here's what the POST data looks like for this request: The model binder and it's straight form based POST mechanism is great for posting data directly from HTML pages to model objects. It avoids having to do manual conversions for many operations and is a great boon for AJAX callback requests. Using Web API JSON Formatter The other option is to post data using a JSON string. The process for this is similar except that you create a JavaScript object and serialize it to JSON first.album = { AlbumName: "PowerAge", Entered: new Date(1977,0,1) } $.ajax( { url: "albums/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify(album), success: function (result) { alert(result); } }); Here the data is sent using a JSON object rather than form data and the data is JSON encoded over the wire. The trace reveals that the data is sent using plain JSON (Source above), which is a little more efficient since there's no UrlEncoding that occurs. BTW, notice that WebAPI automatically deals with the date. I provided the date as a plain string, rather than a JavaScript date value and the Formatter and ModelBinder both automatically map the date propertly to the Entered DateTime property of the Album object. Passing multiple Parameters to a Web API Controller Single parameters work fine in either of these RPC scenarios and that's to be expected. ModelBinding always works against a single object because it maps a model. But what happens when you want to pass multiple parameters? Consider an API Controller method that has a signature like the following:[HttpPost] public string PostAlbum(Album album, string userToken) Here I'm asking to pass two objects to an RPC method. Is that possible? This used to be fairly straight forward either with WCF REST and ASP.NET AJAX ASMX services, but as far as I can tell this is not directly possible using a POST operation with WebAPI. There a few workarounds that you can use to make this work: Use both POST *and* QueryString Parameters in Conjunction If you have both complex and simple parameters, you can pass simple parameters on the query string. The above would actually work with: /album/PostAlbum?userToken=sekkritt but that's not always possible. In this example it might not be a good idea to pass a user token on the query string though. It also won't work if you need to pass multiple complex objects, since query string values do not support complex type mapping. They only work with simple types. Use a single Object that wraps the two Parameters If you go by service based architecture guidelines every service method should always pass and return a single value only. The input should wrap potentially multiple input parameters and the output should convey status as well as provide the result value. You typically have a xxxRequest and a xxxResponse class that wraps the inputs and outputs. Here's what this method might look like:public PostAlbumResponse PostAlbum(PostAlbumRequest request) { var album = request.Album; var userToken = request.UserToken; return new PostAlbumResponse() { IsSuccess = true, Result = String.Format("{0} {1:d} {2}", album.AlbumName, album.Entered,userToken) }; } with these support types:public class PostAlbumRequest { public Album Album { get; set; } public User User { get; set; } public string UserToken { get; set; } } public class PostAlbumResponse { public string Result { get; set; } public bool IsSuccess { get; set; } public string ErrorMessage { get; set; } }   To call this method you now have to assemble these objects on the client and send it up as JSON:var album = { AlbumName: "PowerAge", Entered: "1/1/1977" } var user = { Name: "Rick" } var userToken = "sekkritt"; $.ajax( { url: "samples/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify({ Album: album, User: user, UserToken: userToken }), success: function (result) { alert(result.Result); } }); I assemble the individual types first and then combine them in the data: property of the $.ajax() call into the actual object passed to the server, that mimics the structure of PostAlbumRequest server class that has Album, User and UserToken properties. This works well enough but it gets tedious if you have to create Request and Response types for each method signature. If you have common parameters that are always passed (like you always pass an album or usertoken) you might be able to abstract this to use a single object that gets reused for all methods, but this gets confusing too: Overload a single 'parameter' too much and it becomes a nightmare to decipher what your method actual can use. Use JObject to parse multiple Property Values out of an Object If you recall, ASP.NET AJAX and WCF REST used a 'wrapper' object to make default AJAX calls. Rather than directly calling a service you always passed an object which contained properties for each parameter: { parm1: Value, parm2: Value2 } WCF REST/ASP.NET AJAX would then parse this top level property values and map them to the parameters of the endpoint method. This automatic type wrapping functionality is no longer available directly in Web API, but since Web API now uses JSON.NET for it's JSON serializer you can actually simulate that behavior with a little extra code. You can use the JObject class to receive a dynamic JSON result and then using the dynamic cast of JObject to walk through the child objects and even parse them into strongly typed objects. Here's how to do this on the API Controller end:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } This is clearly not as nice as having the parameters passed directly, but it works to allow you to pass multiple parameters and access them using Web API. JObject is JSON.NET's generic object container which sports a nice dynamic interface that allows you to walk through the object's properties using standard 'dot' object syntax. All you have to do is cast the object to dynamic to get access to the property interface of the JSON type. Additionally JObject also allows you to parse JObject instances into strongly typed objects, which enables us here to retrieve the two objects passed as parameters from this jquery code:var album = { AlbumName: "PowerAge", Entered: "1/1/1977" } var user = { Name: "Rick" } var userToken = "sekkritt"; $.ajax( { url: "samples/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify({ Album: album, User: user, UserToken: userToken }), success: function (result) { alert(result); } }); Summary ASP.NET Web API brings many new features and many advantages over the older Microsoft AJAX and REST APIs, but realize that some things like passing multiple strongly typed object parameters will work a bit differently. It's not insurmountable, but just knowing what options are available to simulate this behavior is good to know. Now let me say here that it's probably not a good practice to pass a bunch of parameters to an API call. Ideally APIs should be closely factored to accept single parameters or a single content parameter at least along with some identifier parameters that can be passed on the querystring. But saying that doesn't mean that occasionally you don't run into a situation where you have the need to pass several objects to the server and all three of the options I mentioned might have merit in different situations. For now I'm sure the question of how to pass multiple parameters will come up quite a bit from people migrating WCF REST or ASP.NET AJAX code to Web API. At least there are options available to make it work.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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