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  • Is it a bad practice to have an interface to define constants?

    - by FabianB
    I am writing a set of junit test classes in java. There are several constants, for example strings that I will need in different test classes. I am thinking about an interface that defines them and every test class would implement it. The benefits I see there are: easy access to constants: "MY_CONSTANT" instead of "ThatClass.MY_CONSTANT" each constant defined only once Is this approach rather a good or bad practice? I feel like abusing the concept of interfaces a little bit. You can answer generally about interfaces/constants, but also about unit tests if there is something special about it.

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  • C# Reflection: How to call method of interface without creating instance?

    - by jitm
    Hello, I have situation where I have to call method of interface using reflection, like this object x = null; MethodInfo method = interfaceExists.GetMethod("ShutDown"); method.Invoke(x, new object[] { 4 }) As you can see I do not create instance of object! And, as I can supposed, I receive exception Non-static method requires a target And Question, Can I call method of interface using reflection without creating instance of interface and if YES, How I can do it ? Thank you.

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  • Filtering SQLAlchemy query on attribute_mapped_collection field of relationship

    - by bsa
    I have two classes, Tag and Hardware, defined with a simple parent-child relationship (see the full definition at the end). Now I want to filter a query on Tag using the version field in Hardware through an attribute_mapped_collection, eg: def get_tags(order_code=None, hardware_filters=None): session = Session() query = session.query(Tag) if order_code: query = query.filter(Tag.order_code == order_code) if hardware_filters: for k, v in hardware_filters.iteritems(): query = query.filter(getattr(Tag.hardware, k).version == v) return query.all() But I get: AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with Tag.hardware has an attribute 'baseband The same thing happens if I strip it back by hard-coding the attribute, eg: query.filter(Tag.hardware.baseband.version == v) I can do it this way: query = query.filter(Tag.hardware.any(artefact=k, version=v)) But why can't I filter directly through the attribute? Class definitions class Tag(Base): __tablename__ = 'tag' tag_id = Column(Integer, primary_key=True) order_code = Column(String, nullable=False) version = Column(String, nullable=False) status = Column(String, nullable=False) comments = Column(String) hardware = relationship( "Hardware", backref="tag", collection_class=attribute_mapped_collection('artefact'), ) __table_args__ = ( UniqueConstraint('order_code', 'version'), ) class Hardware(Base): __tablename__ = 'hardware' hardware_id = Column(Integer, primary_key=True) tag_id = Column(String, ForeignKey('tag.tag_id')) product_id = Column(String, nullable=True) artefact = Column(String, nullable=False) version = Column(String, nullable=False)

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  • iOS 7 sur iPad : les premières vraies images, nouvelle interface et nouvelles fonctionnalités arrivent avec la beta 2 du système

    iOS 7 sur iPad : les premières vraies images Nouvelle interface et nouvelles fonctionnalités arrivent avec la beta 2 du systèmeLes spéculations sur ce que sera iOS 7 pour iPad continuent. Sauf que depuis ce lundi, Apple a effectivement sorti une pré-version du système (la beta 2) compatible avec les tablettes de la marque.Malgré une clause de confidentialité censée empêcher les développeurs qui la testent d'en parler, de nombreuses captures d'écrans et des vidéos ? cette fois-ci réelles ? sont apparues dans la journée.Pas d'immense nouveauté côté fonctionnalités à noter par rapport à la version pour iPhone/iPad (Photobooth, retour des mémos voix, nouvelle manière de passer d'une application ouver...

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  • AS3 - Can I know if a class implements an interface (or is a subclass of another class) ?

    - by lk
    With this code function someFunction(classParam:Class):Boolean { // how to know if classParam implements some interface? } i.e. Comparing classParam with IEventDispatcher interface: someFunction(EventDispatcher) // returns true someFunction(Object) // returns false I know it can't be done with is operator. But, is there a way to do it? Is there a way to know if a class implements some interface? (or is a subclass of another class?)

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  • How can I troubleshoot a "Hardware Malfunction" blue screen?

    - by AaronSieb
    My computer has suddenly started crashing to a blue screen with the following text: hardware malfunction call your hardware vendor for support *the system has halted* The crash occurs randomly during normal use. I have thus far always been able to reproduce it by transferring the contents of a large folder... But I'm not sure if this is caused by the file transfer, or simply because the transfer takes long enough for something else to trigger it. A bit about my hardware I have an dual core Intel CPU, and Asus motherboard. Video card is by nVidia, and connects via PCIe. My hard drives are in pairs, and connect via SATA to a RAID controller on the motherboard. They are configured to use a RAID0 configuration. What I've tried so far There is nothing in the Windows Event Log. WhoCrashed was unable to find any crash records. ScanDisk runs to completion (it launches prior to Windows load) and reports no errors. MemTest reports no errors (to 200% coverage). System temperatures are in the range of 40 to 50 degrees Celsius, with video card temperatures in the range of 60 to eighty degrees Celsius. I have stripped the system down to a minimal configuration (hard drive, video card, one memory module, motherboard, CPU, power supply). The problem still occurrs. However, this has allowed me to rule out a few components: It is not the video card because the problem still occurred after replacing the video card another one I had on hand. It is not the hard drive or anything software related because the problem occurred after a fresh installation of Windows on a replacement hard drive. It is not the hard drive cables because I replaced those with new ones and still had the problem. It is not the power supply because the problem still occurred after replacing the power supply with another one I had on hand. It is probably not the memory because I've tried three different memory modules in three different memory slots and was still able to replicate the issue. Is there anything I can do to confirm what's causing the issue? At the moment it seems as though it must be either the motherboard or CPU, but those are both difficult components to replace... In addition, both components are relatively new (two to three years old). I will gladly edit in any additional information I can get my hands on, and/or focus the question as I can find more details...

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  • Is there a test to see if hardware virtualization (vmx / xvm) are presently enabled within a Linux session?

    - by Dr. Edward Morbius
    I'm writing procedures for configuring VirtualBox support for 64-bit SMP guests, which requires hardware virtualization suppot (VTx/Intel, AMD-V/AMD). I have successfully configured this myself, however I'd like the procedure to be clear. sed -ne '/^flags/s/^.*: //p' /proc/cpuinfo | egrep -q '(vmx|svm)' && echo Has hardware virt || echo No HW virt ... shows if the CPU is capable. I've still got to go enable the feature in BIOS. Any way to test from within Linux to see that this is no or not? Thanks.

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  • What are the minimum hardware requirements for the latest version of Android Jelly Bean OS?

    - by Stom
    I searched around, and there's no information that points exactly to the suggested, minimum, or otherwise dated information containing specifications on this. I want to install a newer version of Android on an older ZTE-X500 MetroPCS smartphone. However, I'd like to know the backwards compatibility in regards to using a newer featured OS with lackluster, limited hardware compared to today's smartphones, such as Galaxy S4. However, I still wish to do this. If Jelly Bean is too demanding, I will set up Honeycomb, or get a modified Honey Comb ROM, or tweak the source to my preferences. However, nothing outlines the specifics of the "system requirements" it suggests for optimum performance, such as RAM, processor speed, processor features, and/or any other features, like DMA, video circuit advancements, and/or sound and special hardware requirements noted as well. Please, if you will, point me to a source that mentions this, and please tell do not link me to any PDF file formats. Thank you. PS: I'm a computer programmer.

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  • Why is windows 7 marking all my extra RAM as "hardware reserved"?

    - by pinkmuppet
    I have a new HP Z800 Workstation, running Windows 7 Enterprise 64 bit. The machine has 4GB of RAM -- windows reported 1.99GB available, 2GB was "hardware reserved". I added another 2 GB and windows reports that there is 6GB of physical RAM, but now 4GB is "hardware reserved". The BIOS sees the full RAM amount as well. The video card is an nVida Quadro FX 580, so it shouldn't be using any shared memory at all. whats going on? Z800 Specs are here.

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  • Is there such thing as hardware encrypted raid disk?

    - by Dumitrescu Bogdan
    I have a server for which I want to protect the content. The server is located on a clients premises. Is there a way to encrypt the content of a RAID DISK (at hardware level) ? What I need is that the server will not be able to start as long as the required password is not provided (the encryption key) I will give the best answer to Miles, though the answer was not exactly to my question. But from all the comments, it seems that it cannot be done hardware or .. it cannot be done as I would like to.

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  • With CentOS 6 and LXC, "ifconfig" is unable to see network interface (but busybox "ifconfig" works fine)

    - by larsks
    I've just started working with LXC under CentOS 6 (via the libvirt adapter). If I create an LXC container, I'm unable to see any network interfaces when using the native system tools: # ifconfig -a # The behavior is very odd; specifying an interface by names yields neither the expected output nor an error message. This is true even for clearly invalid interface names, like this: # ifconfig foo # The ip command exhibits the same behavior. On the other hand, if I use "ifconfig" provided by busybox, everything works as expected: # busybox ifconfig -a eth0 Link encap:Ethernet HWaddr 52:54:00:E0:12:C8 inet6 addr: fe80::5054:ff:fee0:12c8/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:268 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:17814 (17.3 KiB) TX bytes:552 (552.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) So...what does busybox know that the native tools don't? The libvirt config for this environment is pretty standard; the network definition looks like this: <interface type='network'> <mac address='52:54:00:e0:12:c8'/> <source network='default'/> <target dev='veth0'/> </interface> The full configuration is here if you think it might help. I'm running: lxc-0.7.2-2.el6.x86_64 kernel-2.6.32-71.29.1.el6.x86_64 EDIT Weirder and weirder...it's a display issue, not a functionality issue. I can see the output of ifconfig if I pipe it into anything, so for example: # ifconfig eth0 | cat eth0 Link encap:Ethernet HWaddr 52:54:00:E0:12:C8 inet addr:192.168.10.10 Bcast:192.168.10.255 Mask:255.255.255.0 inet6 addr: fe80::5054:ff:fee0:12c8/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:573 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:37914 (37.0 KiB) TX bytes:552 (552.0 b) And in fact even when not piping the output, strace shows that ifconfig is in fact writing the output to file descriptor 1 (aka stdout), so it's not clear why no output is actually showing up. This could be either an LXC or a virsh issue, I guess.

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  • Is there a test to see if hardware virtualization (vmx / svm) are presently enabled within a Linux session?

    - by Dr. Edward Morbius
    I'm writing procedures for configuring VirtualBox support for 64-bit SMP guests, which requires hardware virtualization suppot (VTx/Intel, AMD-V/AMD). I have successfully configured this myself, however I'd like the procedure to be clear. sed -ne '/^flags/s/^.*: //p' /proc/cpuinfo | egrep -q '(vmx|svm)' && echo Has hardware virt || echo No HW virt ... shows if the CPU is capable. I've still got to go enable the feature in BIOS. Any way to test from within Linux to see that this is no or not? Thanks. (Edit: s/xvm/svm/ in title)

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  • Can a power failure or forceful shutdown damage hardware?

    - by Vilx-
    Can computer hardware suffer damage from forceful shutdowns (holding the power button for five (5) seconds) or power failures? I believe that normal PC hardware does not suffer from this - after all, it's not much different than what they experience under a standard shutdown. But elsewhere I've read tht another person thought that it could do physical harm to the hard drive and possibly other components as well. He also said that the journaling features of filesystems are useless in face of power failures and were intended to help mitigate damage from system crashes. I think this is nonsense, but then again I lack the experience and knowledge to say it with certainty.

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  • Is there any Mac Pro hardware parts that can ONLY be purchased thru Apple?

    - by bigp
    I'd like to know if I need to be concerned about any hardware parts that I should include in a brand new Mac Pro purchase, instead of trying to hunt it down on 3rd party vendors (or whitelist vendors / hardware suppliers). The main components I'm interested for "upgradeability" are: Processors (If starting with Two 2.4GHz Quad-Core "Westmere"); RAM (If starting with the least possible, which seems to be 6 x 1GB); Video Cards (If starting with one ATI Radeon HD 5770, can a 2nd one be purchased elsewhere?) Hard-Drives (Since these are mounted in specialized trays [if I'm not mistaking], are they also sold elsewhere? And can they be bought as SSDs?) Power Supply (Do I need to be concerned about this at all, or does it auto-adjust depending on the new component upgrades?) I just want to be sure by choosing a Mac Pro with lower component specifications that I can in fact purchase upgrade parts cheaper elsewhere. Thanks!

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  • Why are my hardware tabs disabled for my VMWare player image?

    - by djangofan
    I just installed a Ubuntu 10.10 image on VMWare player and after I finished installing I was messing with the hardware settings and I did the following: 1. disabled the floppy device 2. changed the CDRom to "use system cdrom" 3. tried to enable the VMWare tools but it complained that the vm was in "Easy Install" mode After I fiddled with the VM now my floppy and 2 CD rom devices as well as sound card and USB settings are all disabled in the VM hardware settings. Any idea on why this occurred and how to fix it?

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  • Is an I/O benchmark made for hardware an accurate assessment of a Windows VM's performance under vSphere 5?

    - by Jeremy
    We support an enterprise application running on Windows Server 2008 R2. One of our customers has chosen to install to VMWare, and what I'm finding is that the VM's are relatively slow compared to hardware. Our product development team has advised that many VMs appear to run particularly slow on I/O benchmarks, which impact performance in production. I've tried the AttoSoft I/O benchmark and find that for smaller I/O blocks (1-32K) the VM I'm looking at is 25x slower than hardware and for larger I/O blocks (1-8MB) it's 10x slower. Is this a fair benchmark? If not, any suggestions for a fair test?

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  • Hosing website on own server. What is Hardware requirement and Cost [closed]

    - by KuKu
    As i am about to finish my dream website, i need to host it on some server. I checked Amazon AWS Free Tier, i found it pretty complex. As i made full website in java(JSP + Servlet + mysql + Node.js), its been expensive to host. So i thought that why not to host on own server so that i will be fully dependent on my resources, not on any one else. And i know, in future i need to pay more and more to the other hosting company(because of uploading images and number of incoming users). So my question is, On initial stage what kind of hardware i will required. What can be the cost of that hardware? I already have 12MBPS broadband connection, will it be sufficient? It has static IP Address as well.

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  • ODI 11g – Oracle Multi Table Insert

    - by David Allan
    With the IKM Oracle Multi Table Insert you can generate Oracle specific DML for inserting into multiple target tables from a single query result – without reprocessing the query or staging its result. When designing this to exploit the IKM you must split the problem into the reusable parts – the select part goes in one interface (I named SELECT_PART), then each target goes in a separate interface (INSERT_SPECIAL and INSERT_REGULAR). So for my statement below… /*INSERT_SPECIAL interface */ insert  all when 1=1 And (INCOME_LEVEL > 250000) then into SCOTT.CUSTOMERS_NEW (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /* INSERT_REGULAR interface */ when 1=1  then into SCOTT.CUSTOMERS_SPECIAL (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /*SELECT*PART interface */ select        CUSTOMERS.EMAIL EMAIL,     CUSTOMERS.CREDIT_LIMIT CREDIT_LIMIT,     UPPER(CUSTOMERS.NAME) NAME,     CUSTOMERS.USER_MODIFIED USER_MODIFIED,     CUSTOMERS.DATE_MODIFIED DATE_MODIFIED,     CUSTOMERS.BIRTH_DATE BIRTH_DATE,     CUSTOMERS.MARITAL_STATUS MARITAL_STATUS,     CUSTOMERS.ID ID,     CUSTOMERS.USER_CREATED USER_CREATED,     CUSTOMERS.GENDER GENDER,     CUSTOMERS.DATE_CREATED DATE_CREATED,     CUSTOMERS.INCOME_LEVEL INCOME_LEVEL from    SCOTT.CUSTOMERS   CUSTOMERS where    (1=1) Firstly I create a SELECT_PART temporary interface for the query to be reused and in the IKM assignment I state that it is defining the query, it is not a target and it should not be executed. Then in my INSERT_SPECIAL interface loading a target with a filter, I set define query to false, then set true for the target table and execute to false. This interface uses the SELECT_PART query definition interface as a source. Finally in my final interface loading another target I set define query to false again, set target table to true and execute to true – this is the go run it indicator! To coordinate the statement construction you will need to create a package with the select and insert statements. With 11g you can now execute the package in simulation mode and preview the generated code including the SQL statements. Hopefully this helps shed some light on how you can leverage the Oracle MTI statement. A similar IKM exists for Teradata. The ODI IKM Teradata Multi Statement supports this multi statement request in 11g, here is an extract from the paper at www.teradata.com/white-papers/born-to-be-parallel-eb3053/ Teradata Database offers an SQL extension called a Multi-Statement Request that allows several distinct SQL statements to be bundled together and sent to the optimizer as if they were one. Teradata Database will attempt to execute these SQL statements in parallel. When this feature is used, any sub-expressions that the different SQL statements have in common will be executed once, and the results shared among them. It works in the same way as the ODI MTI IKM, multiple interfaces orchestrated in a package, each interface contributes some SQL, the last interface in the chain executes the multi statement.

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  • Network traffic is not being forwarded from a VM to the network using a bridged interface with Xen + libvirt

    - by foob
    I'm having trouble getting network access from a VM that I'm running using Xen and libvirt. I've been trying different things and reading similar posts online for a couple of days but I'm really stuck at this point. If anybody could offer some insight it would be much appreciated. I have a VM that I'm running on a host with a bridge set up as br0 and an interface eth0 on a 192.168.60.0/24 subnet. The networking portion of the libvirt configuration xml is: <interface type='bridge'> <mac address='ff:a0:d1:e5:07:de'/> <source bridge='br0'/> <script path='/etc/xen/scripts/vif-bridge'/> <model type='virtio' /> </interface> When I start the VM a vif6.0 interface is created on the host and the ifconfig output is: br0 Link encap:Ethernet HWaddr 00:A0:D1:C3:07:DE inet addr:192.168.60.33 Bcast:192.168.60.255 Mask:255.255.255.0 inet6 addr: fe80::2a0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13 errors:0 dropped:0 overruns:0 frame:0 TX packets:40 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:3570 (3.4 KiB) TX bytes:3508 (3.4 KiB) eth0 Link encap:Ethernet HWaddr 00:A0:D1:C3:07:DE inet6 addr: fe80::2a0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:492 (492.0 b) Interrupt:19 Memory:fe8f0000-fe900000 vif6.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:80 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:6660 (6.5 KiB) TX bytes:468 (468.0 b) virbr0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) The 'brctl show' output seems to show the bridge being configured correctly: br0 8000.00a0d1e507de no eth0 vif6.0 The ifcfg-eth0 contents in the VM are: DEVICE=eth0 BOOTPROTO=static HWADDR=FF:A0:D1:E5:07:DE IPADDR=192.168.60.133 NETMASK=255.255.255.0 ONBOOT=yes and the output of ifconfig in the VM look like what I would expect: eth0 Link encap:Ethernet HWaddr FF:A0:D1:E5:07:DE inet addr:192.168.60.133 Bcast:192.168.60.255 Mask:255.255.255.0 inet6 addr: fe80::fda0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:80 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:468 (468.0 b) TX bytes:7780 (7.5 KiB) but when I try to ssh or ping another computer I get 'no route to host.' Using tcpdump on the host system I tried to see if I could narrow down where the problem is: # tcpdump -vv -i vif6.0 tcpdump: WARNING: vif6.0: no IPv4 address assigned tcpdump: listening on vif6.0, link-type EN10MB (Ethernet), capture size 96 bytes 14:49:40.833997 arp who-has 192.168.60.35 tell 192.168.60.133 14:49:41.833314 arp who-has 192.168.60.35 tell 192.168.60.133 14:49:42.833309 arp who-has 192.168.60.35 tell 192.168.60.133 So the VM is sending out out an arp who-has packet when I try to ssh to 192.168.60.35. I think that this means the setup within the VM is ok and that this is an issue on the host system. If I run tcpdump with the interface of br0 then I don't see these arp packets. My thought here is that the packets are being blocked before going on to the bridge somehow. I tried adding an iptables rule to resolve this: -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT but it didn't work. I also tried the following: /sbin/sysctl -w net.bridge.bridge-nf-call-ip6tables=0 /sbin/sysctl -w net.bridge.bridge-nf-call-iptables=0 /sbin/sysctl -w net.bridge.bridge-nf-call-arptables=0 /sbin/sysctl -w net.ipv4.ip_forward=1 which had no impact. Is it obvious to somebody who has more experience than me what I'm missing here? Should vif6.0 have the same MAC address is eth0 in the vm? Do I need more rules in my iptables? Thanks for any help!

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  • What is the correct UI interface to learn for creating Windows phone 8 apps? [closed]

    - by Robert Oschler
    I am a veteran Delphi 6 programmer transitioning to C# development. My first project is a open source library that will have a minimal user interface since it is meant to be used as a Component primarily on desktop PCs running Visual Studio. My next project is going to be a Windows 8 phone app and I intend for that platform to be my primary focus for future C# development, not the desktop. My concern is that I waste as little time as possible learning a presentation framework that will benefit or distract me from writing Windows 8 phone apps. The plethora of framework names I have already encountered include, WinForms, WPF (Windows Presentation Framework), Silverlight, Silverlight Mobile, Metro and there may be others. Given my goal outlined in the first paragraph above, I have a few questions: 1) Which of the frameworks should I use for the small amount of UI work I will do with the desktop Component project that will help me the most, or hurt me the least, when I move to Windows 8 phone app development? 2) Which is the correct framework to study for developing Windows 8 phone apps? 3) Any awesome tutorials, resources or books you have run into targeted towards veteran programmers from other platforms? I read about the Portable Library Tools on this Stack Overflow thread: http://stackoverflow.com/questions/5522355/windows-phone-7-wpf-sharing-a-codebase But the reply by Simon Guindon seemed to indicate to me that it's not the best solution for writing a competitive Windows 8 phone app.

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  • What is the rationale behind Apache Jena's *everything is an interface if possible* design philosophy?

    - by David Cowden
    If you are familiar with the Java RDF and OWL engine Jena, then you have run across their philosophy that everything should be specified as an interface when possible. This means that a Resource, Statement, RDFNode, Property, and even the RDF Model, etc., are, contrary to what you might first think, Interfaces instead of concrete classes. This leads to the use of Factories quite often. Since you can't instantiate a Property or Model, you must have something else do it for you --the Factory design pattern. My question, then, is, what is the reasoning behind using this pattern as opposed to a traditional class hierarchy system? It is often perfectly viable to use either one. For example, if I want a memory backed Model instead of a database-backed Model I could just instantiate those classes, I don't need ask a Factory to give me one. As an aside, I'm in the process of writing a library for manipulating Pearltrees data, which is exported from their website in the form of an RDF/XML document. As I write this library, I have many options for defining the relationships present in the Peartrees data. What is nice about the Pearltrees data is that it has a very logical class system: A tree is made up of pearls, which can be either Page, Reference, Alias, or Root pearls. My question comes from trying to figure out if I should adopt the Jena philosophy in my library which uses Jena, or if I should disregard it, pick my own design philosophy, and stick with it.

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  • Can I assume interface oriented programming as a good object oriented programming?

    - by david
    I have been programming for decades but I have not been used to object oriented programming. But for recenet years, I had a great opportunity to learn OOP, its principles, and a lot of patterns that are great. Since I've learned OOP, I tried to apply them to a couple of projects and found those projects successful. Unfortunately I didn't follow extreme programming that suggests writing test first, mainly because their time frame were tight. What I did for those projects were Identify all necessary classes and create them with proper properties and methods whenever there is dependency between classes, write interface between them see if there is any patterns for certain relationships between classes to replace By successful, I meant that it was quick development effort, the classes can be reused better, and flexible enough so that another programmer does not have to change something else to fix another part. But I wonder if this is a good practice. Of course, I know I need to put writing unit tests first in my work process. But other than that, is there any problem with this approach - creating lots of interfaces - in long term?

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