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  • Can I implement the readers and writers algorithm in OpenMP by replacing counting semaphores with another feature?

    - by DeveloperDon
    After reading about OpenMP and not finding functions to support semaphores, I did an internet search for OpenMP and the readers and writers problem, but found no suitable matches. Is there a general method for replacing counting semaphores in OpenMP with something that it supports? Or is there just a gap in the environment where it does not permit things that are asymmetrical like the third readers and writers problem shown on the following page? http://en.wikipedia.org/wiki/Readers-writers_problem#The_third_readers-writers_problem

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  • How can I use multiple meshes per entity without breaking one component of a single type per entity?

    - by Mathias Hölzl
    We are just switching from a hierarchy based game engine to a component based game engine. My problem is that when I load a model which has has a hierarchy of meshes and the way I understand is that a entity in a component based system can not have multiple components of the same type, but I need a "meshComponent" for each mesh in a model. So how could I solve this problem. On this side they implemented a Component based game engine: http://cowboyprogramming.com/2007/01/05/evolve-your-heirachy/

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  • Simple Netduino Go Tutorial Flashing RGB LEDs with a potentiometer

    - by Chris Hammond
    In case you missed the announcement on 4/4, the guys and Secret Labs, along with other members of the Netduino Community have come out with a new platform called Netduino Go . Head on over www.netduino.com for the introduction forum post . This post is how to quickly get up and running with your Netduino Go, based on Chris Walker’s getting started forum post , with some enhancements that I think will make it easier to get up and running, as Chris’ post unfortunately leaves a few things out. Hardware...(read more)

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  • Messages stuck in SMTP queue - Exchange 2003

    - by Diav
    I need your help people ;-) I have a problem with messages coming into our Exchange Server and ones going out through it. Basically, the messages are stuck in the SMTP queue. A message will come into the server, I can see it listed under "Exchange System Manager", but if you list the properties of the message queue it says something like 00:10 SMTP Message queued for local delivery 00:10 SMTP Message delivered locally to [email protected] 00:10 SMTP Message scheduled to retry local delivery 00:11 SMTP Message delivered locally to [email protected] 00:11 SMTP Message scheduled to retry local delivery etc etc For outgoing message list looks like this: 10:55 SMTP: Message Submitted to Advanced Queuing 10:55 SMTP: Started Message Submission to Advanced Queue 10:55 SMTP: Message Submitted to Categorizer 10:55 SMTP: Message Categorized and Queued for Routing 10:55 SMTP: Message Routed nad Queued for Remote Delivery And the end - since then status didn't change, message is in queue, I am forcing connection from time to time but without an effect. I checked connection with smarthost (used telnet for that) and everything seems to work correctly, so the problem is probably on exchange side. I am using Exchange Server 2003 running on Small Business Server 2003. I don't have any antivirus installed on server. Remaining free space on each partition is over 3Gb, on partition with data bases - it is over 12Gb. All was working good and without problems since 2005, problems started in half of this june - messages started going out and being stuck almost randomly (I don't see a pattern yet, some are going out, some are not, some are going after several hours). I don't know what to do, what to check more, so please, any ideas? Best regards, D. edit Priv1.edb has 14,5GB and priv1.stm 2,6GB - together those files have more than 16GB - can it be the reason? If yes, then what? Indeed, I haven't thought that it can have something in common with my problem, but several users reported recent problems with Outlook Web Access - they can log in, they see the list of their mails, but they can't see the content of their emails. Although when they are connecting with Outlook 2003/2007 - there is no such problem, only with OWA there is. edit2 So,.. It works now, and I have to admit that I am not really sure what the problem was (hope it won't come back). What have I done: Cleaned up some mailboxes to reduce size of them Dismounted Information Store Defragmentated data base files ( I used eseutil: c:\program files\exchsrvr\bin eseutil /d g:\data base\Exchsrvr\MDBDATA\priv1.edb ) Mounted Information Store back ..and before I managed to do anything else - my queue started moving, elements which were kept there already for days - started moving and after few minutes everything was sent, both, outside and locally. But: priv1.edb is still big (13 884 203 008), priv1.stm as well (2 447 384 576), so this is probably not the issue of size of the file. And if not this, so what was that? And if that was issue of size of the file, then soon it will repeat - is there something I can do to avoid it ?

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  • Gnome Tweak Tool problems

    - by Nguy?n Duy Khánh
    I am now using Ubuntu 12.10 and I tried to install Gnome Shel Extension and Gnome Tweak Tool. However, here is my problem : You can see that my tweak tool does not receive user themes.. When I checked the Ubuntu Software Center, I see that GNOME Shell Extension Preferences and GNOME Shel User Themes has already installed. So, what is my problem, and how can I fix it ? Please help me. Thanks.

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  • after new install 12.04 black screen with blinking cursor

    - by gregor
    I installed 12.04 and I got after boot black screen.Next I started in filesafe mode but filesafeX (all options)do not work(black screen.Then I started root shell , remounted rw HD and on prompt built xorg.conf with: $X -configure I have edited xorg.conf to delete obsolete monitors and screens. After reboot I get black screen with blinking cursor (no terminals) what can I do? how to edit xorg.conf when this could be a problem?## Heading ## hardware:radeon hd5470 and i3 with i915

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  • Permanently delete / hide a buddylist in Empathy

    - by jP_wanN
    I'm using Ubuntu 12.04 and I have a problem using empathy. I added all of my contacts to gnome-contacts and linked them with the facebook-contacts from empathy. Now they show twice in Empathy, once in the list Facebook-Friends and once in Personal. The problem is that the list Facebook-Friends is the upper one and if i minimize or delete it it gets recovered when I restart empathy, but I need to see the Personal-list because it has all my contacts, those from Facebook and those from Google Talk.

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  • WebLogic 12c hands-on bootcamps for partners – free of charge

    - by JuergenKress
    For all WebLogic Partner Community members we offer our WebLogic 12c hands-on Bootcamps – free of charge! If you want to become an Application Grid Specialized: Register Here! Country Date Location Registration Germany 3-5 April 2012 Oracle Düsseldorf Click here France 24-26 April 2012 Oracle Colombes Click here Spain 08-10 May 2012 Oracle Madrid Click here Netherlands 22-24 May 2012 Oracle Amsterdam Click here United Kingdom 06-08 June 2012 Oracle Reading Click here Italy 19-21 June 2012 Oracle Cinisello Balsamo Click here Portugal 10-12 July 2012 Oracle Lisbon Click here Skill requirements Attendees need to have the following skills as this is required by the product-set and to make sure they get the most out of the training: Basic knowledge in Java and JavaEE Understanding the Application Server concept Basic knowledge in older releases of WebLogic Server would be beneficial Member of WebLogic Partner Community for registration please vist http://www.oracle.com/partners/goto/wls-emea Hardware requirements Every participant works on his own notebook. The minimal hardware requirements are: 4Gb physical RAM (we will boot the image with 2Gb RAM) dual core CPU 15 GB HD Software requirements Please install Oracle VM VirtualBox 4.1.8 Follow-up and certification With the workshop registration you agree to the following next steps Follow-up training attend and pass the Oracle Application Grid Certified Implementation Specialist Registration For details and registration please visit Register Here Free WebLogic Certification (Free assessment voucher to become certified) For all WebLogic experts, we offer free vouchers worth $195 for the Oracle Application Grid Certified Implementation Specialist assessment. To demonstrate your WebLogic knowledge you first have to pass the free online assessment Oracle Application Grid PreSales Specialist. For free vouchers, please send an e-mail with the screenshot of your Oracle Application Grid PreSales certirficate to [email protected] including your Name, Company, E-mail and Country. Note: This offer is limited to partners from Europe Middle East and Africa. Partners from other countries please contact your Oracle partner manager. WebLogic Specialization To become specialized in Application Grid, please make sure that you access the: Application Grid Specialization Guide Application Grid Specialization Checklist If you have any questions please contact the Oracle Partner Business Center. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: WebLogic training,Java training,WebLogic 12c,WebLogic Community,OPN,WebLogic,Oracle,WebLogic Certification,Apps Grid Certification,Implementation Specialist,Apps Grid Specialist,Oracle education

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  • PASS 13 Dispatches: moving to the cloud

    - by Tony Davis
    PASS Summit 13, Day 1 keynote by Quentin Clarke and we're hearing about “redefiniing mission critical in the cloud”. With a move to the Windows Azure cloud comes the promise of capacity on demand, automatic HA, backups, patching and so on, as well as passing responsibility to MS for managing hardware, upgrades and so on. However, for many databases and applications the best route to the cloud is not necessarily obvious. For most, the path of least resistance is IaaS – SQL Server in a Azure VM. It removes the hardware burden but you still have to manage your databases and implementing HA for SQL Server is your responsibility. Also, scaling up comes at quite a cost – the biggest VM (8 CPU cores, 56 GB RAM, 16 1TB drives with 500 IOPS each) weighs in at over over $4500 per month. With PaaS, in the form of Windows SQL Database, you get a “3-copies replica set” so HA comes out-of the box, and removes the majority of the administration burden, but you are moving your database into a very different environment. For a start, it's a shared environment, with other customers using the same compute nodes in the cluster, and potentially even sharing the same database (multi-tenancy). Unless you pay for SQL DB Premium edition, the resources available for your workload will depends on how nicely others “play” in the shared environment. You'll potentially need to do a lot of tuning, and application rewriting to avoid throttling issues, optimising application-database communication to deal with increased latency between the two, and so on. You'll need aggressive application caching. You'll also need retry logic and to deal with (expected) node failure and the need to reconnect. In Tuesday's PASS Summit pre-con from the SQLCAT team, they spent a lot of time covering some of the telemetric techniques (collect into Azure storage the necessary monitoring data) to perform capacity planning, work out the hotspots and bottlenecks in your cloud applications. Tools like WAD (Windows Azure Diagnostics), performance counters SQL Database DMVs, and others, will be essential. Of course, to truly exploit the vast horizontal scaling that is available from the existence of thousands of compute nodes, you'll also need to need to consider how to “shard” your data so Azure can move it between nodes at will. Finding the right path to the Cloud isn't easy, but it's coming. I spoke to people one year ago who saw no real benefit in trying to move their infrastructure and databases to the cloud, but now at their company, it's the conversation that won't go away. Tony.  

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  • A Technique for Performing Cross-host Upgrades to FMW 11gR1

    - by reza.shafii
    The main tool used for the upgrade of iAS 10g mid-tier (data not stored in 10g meta-data repository schemas) environments to Fusion Middleware (FMW) 11gR1 is the FMW Upgrade Assistant (UA). This tool performs what we call an out-of-place upgrade which in a nut-shell means the following: Upgrade is performed by pointing the UA to a 10g source topology as well as an 11g destination topology. The destination topology must be created, using the standard FMW 11g installation and configuration process, prior to the execution of the UA. The UA carries over all of the required changes from the source environment to the destination. This approach has a number of advantages rooted in the fact that the source environment - which is presumably working well and serving its needs - is not disturbed during the upgrade process as the UA only performs read-only operations on it. The UA today can only perform such out-of-place upgrades when the source and destination topologies reside on the same machine. This can sometimes be an issue when the host on which the iAS 10g environment is installed is running at full capacity and installing new hardware for the purpose of the upgrade (in most cases what would be needed is extra memory) is completely infeasible. In such cases, upgrade across a different host is still possible by using the following technique: Backup your source environment and restore it on to a target machine. The backup and restore procedures for the iAS 10.1.2 components are described within this section of the release's Administration Guide. As described in the docs, the Oracle Application Server Backup and Recovery Tool provides capabilities for backing up the installation on one machine and restoring it on another which is exactly what you want to do for the purpose of cross host upgrade. Ensure that the restored environment on your target host is fully functional. Go through the upgrade steps on the target machine to perform the out-of-place upgrade using the UA. Although this process does add another big step to the overall upgrade process, it does make it possible to perform a cross-host upgrade to 11gR1 when necessary. The easiest approach would of course be to find a way of ensuring that the required hardware capacity for upgrade is available on the original 10g host. Using techniques such as scheduling the upgrade at low traffic times and/or temporarily stopping other processes running on the machine to clear up some memory might provide you the sufficient memory needed to perform the out-of-place upgrade and save you the need for using the backup/restore technique I have described in this post.

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  • Oracle Expands Sun Blade Portfolio for Cloud and Highly Virtualized Environments

    - by Ferhat Hatay
    Oracle announced the expansion of Sun Blade Portfolio for cloud and highly virtualized environments that deliver powerful performance and simplified management as tightly integrated systems.  Along with the SPARC T3-1B blade server, Oracle VM blade cluster reference configuration and Oracle's optimized solution for Oracle WebLogic Suite, Oracle introduced the dual-node Sun Blade X6275 M2 server module with some impressive benchmark results.   Benchmarks on the Sun Blade X6275 M2 server module demonstrate the outstanding performance characteristics critical for running varied commercial applications used in cloud and highly virtualized environments.  These include best-in-class SPEC CPU2006 results with the Intel Xeon processor 5600 series, six Fluent world records and 1.8 times the price-performance of the IBM Power 755 running NAMD, a prominent bio-informatics workload.   Benchmarks for Sun Blade X6275 M2 server module  SPEC CPU2006  The Sun Blade X6275 M2 server module demonstrated best in class SPECint_rate2006 results for all published results using the Intel Xeon processor 5600 series, with a result of 679.  This result is 97% better than the HP BL460c G7 blade, 80% better than the IBM HS22V blade, and 79% better than the Dell M710 blade.  This result demonstrates the density advantage of the new Oracle's server module for space-constrained data centers.     Sun Blade X6275M2 (2 Nodes, Intel Xeon X5670 2.93GHz) - 679 SPECint_rate2006; HP ProLiant BL460c G7 (2.93 GHz, Intel Xeon X5670) - 347 SPECint_rate2006; IBM BladeCenter HS22V (Intel Xeon X5680)  - 377 SPECint_rate2006; Dell PowerEdge M710 (Intel Xeon X5680, 3.33 GHz) - 380 SPECint_rate2006.  SPEC, SPECint, SPECfp reg tm of Standard Performance Evaluation Corporation. Results from www.spec.org as of 11/24/2010 and this report.    For more specifics about these results, please go to see http://blogs.sun.com/BestPerf   Fluent The Sun Fire X6275 M2 server module produced world-record results on each of the six standard cases in the current "FLUENT 12" benchmark test suite at 8-, 12-, 24-, 32-, 64- and 96-core configurations. These results beat the most recent QLogic score with IBM DX 360 M series platforms and QLogic "Truescale" interconnects.  Results on sedan_4m test case on the Sun Blade X6275 M2 server module are 23% better than the HP C7000 system, and 20% better than the IBM DX 360 M2; Dell has not posted a result for this test case.  Results can be found at the FLUENT website.   ANSYS's FLUENT software solves fluid flow problems, and is based on a numerical technique called computational fluid dynamics (CFD), which is used in the automotive, aerospace, and consumer products industries. The FLUENT 12 benchmark test suite consists of seven models that are well suited for multi-node clustered environments and representative of modern engineering CFD clusters. Vendors benchmark their systems with the principal objective of providing comparative performance information for FLUENT software that, among other things, depends on compilers, optimization, interconnect, and the performance characteristics of the hardware.   FLUENT application performance is representative of other commercial applications that require memory and CPU resources to be available in a scalable cluster-ready format.  FLUENT benchmark has six conventional test cases (eddy_417k, turbo_500k, aircraft_2m, sedan_4m, truck_14m, truck_poly_14m) at various core counts.   All information on the FLUENT website (http://www.fluent.com) is Copyrighted1995-2010 by ANSYS Inc. Results as of November 24, 2010. For more specifics about these results, please go to see http://blogs.sun.com/BestPerf   NAMD Results on the Sun Blade X6275 M2 server module running NAMD (a parallel molecular dynamics code designed for high-performance simulation of large biomolecular systems) show up to a 1.8X better price/performance than IBM's Power 7-based system.  For space-constrained environments, the ultra-dense Sun Blade X6275 M2 server module provides a 1.7X better price/performance per rack unit than IBM's system.     IBM Power 755 4-way Cluster (16U). Total price for cluster: $324,212. See IBM United States Hardware Announcement 110-008, dated February 9, 2010, pp. 4, 21 and 39-46.  Sun Blade X6275 M2 8-Blade Cluster (10U). Total price for cluster:  $193,939. Price/performance and performance/RU comparisons based on f1ATPase molecule test results. Sun Blade X6275 M2 cluster: $3,568/step/sec, 5.435 step/sec/RU. IBM Power 755 cluster: $6,355/step/sec, 3.189 step/sec/U. See http://www-03.ibm.com/systems/power/hardware/reports/system_perf.html. See http://www.ks.uiuc.edu/Research/namd/performance.html for more information, results as of 11/24/10.   For more specifics about these results, please go to see http://blogs.sun.com/BestPerf   Reverse Time Migration The Reverse Time Migration is heavily used in geophysical imaging and modeling for Oil & Gas Exploration.  The Sun Blade X6275 M2 server module showed up to a 40% performance improvement over the previous generation server module with super-linear scalability to 16 nodes for the 9-Point Stencil used in this Reverse Time Migration computational kernel.  The balanced combination of Oracle's Sun Storage 7410 system with the Sun Blade X6275 M2 server module cluster showed linear scalability for the total application throughput, including the I/O and MPI communication, to produce a final 3-D seismic depth imaged cube for interpretation. The final image write time from the Sun Blade X6275 M2 server module nodes to Oracle's Sun Storage 7410 system achieved 10GbE line speed of 1.25 GBytes/second or better performance. Between subsequent runs, the effects of I/O buffer caching on the Sun Blade X6275 M2 server module nodes and write optimized caching on the Sun Storage 7410 system gave up to 1.8 GBytes/second effective write performance. The performance results and characterization of this Reverse Time Migration benchmark could serve as a useful measure for many other I/O intensive commercial applications. 3D VTI Reverse Time Migration Seismic Depth Imaging, see http://blogs.sun.com/BestPerf/entry/3d_vti_reverse_time_migration for more information, results as of 11/14/2010.                            

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  • Installing device drivers as part of VS2008 setup application (3 replies)

    A colleague in another department has produced device drivers for some USB devices that I need to communicate with in my VS2008 .Net application, and I'm looking to simplify the installation experience for our users. Currently I just put the driver files onto the CD in a folder, and the Windows Add Hardware Wizard will usually take them through the process. What I would like to do though, is to in...

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  • Gparted can't create partition table

    - by William
    Here's what the problem is. About a day or so ago I used Gparted live cd to create 3 NTFS primary partitions on my external 500 gig Goflex and one extended with 2 logical partitiones. I had planned to install windows 8 on the first partition, then ubuntu and kubuntu on the other 2. After I finished partitioning my drive with gparted, I booted into windows vista to make my bootable windows 8 usb to install it with, I also decided to check to make sure all my partitions were working properly. Then I found they were, and they weren't. My 50 gig first partition I had planned to install windows on showed up normal and the 300 gigs of space left in the extended partition did as well, the rest showed up as raw. So I figured alright, something went awal while making the partitions, so I booted up gparted once again. Then to my surprise gparted showed the entire drive as unallocated, and when I refreshed the list, it showed as all the partitions I had made earlier, buy with a exclamation mark by them all. So I figured ok, might be a problem with the partition table as I'd seen a similar problem in past on a drive that was not partitioned at all, so I decided to create a new partition table and take the time out again to sit and wait. Then I got a message saying gparted could not create the partition table, followed by it showing the entire drive as formatted into ntfs. After that I figured ok I'll take a break, come back in a hour, maybe it's something I did. So a hour later I came back after having booted up windows, plugged the drive in to see if by some miracle windows could access the drive. In disk management when I plugged the drive in, it would freeze attempting to read the drive, as I'd seen in the past with raw disks, yet when I unplugged it I got a glimpse of disk management showing it as a perfectly fine ntfs file system on the drive followed by a "you must format disk K in order to use it". So I then was assured the disk was raw as that is what had happened in the past, followed by a new partition table through gparted to fix the problem and a 10 hour format in windows. So I once again booted up gparted, to get the message "error fsyncing/closing/dev/sdg:input/output error" followed by "error opening dev/sdg No such file in directory" after I refreshed and somehow saw the disk show up as perfectly fine ntfs and then tried to create a new partition table to try to wipe out all my problems and start over again. And not gparted only shows the drive there about 1/10 refreshes the rest I get the directory error. If anybody can assist me in any way shape or form I will be thankful.

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  • Has Little Endian won?

    - by espertus
    When teaching recently about the Big vs. Little Endian battle, a student asked whether it had been settled, and I realized I didn't know. Looking at the Wikipedia article, it seems that the most popular current OS/architecture pairs use Little Endian but that Internet Protocol specifies Big Endian for transferring numeric values in packet headers. Would that be a good summary of the current status? Do current network cards or CPUs provide hardware support for switching byte order?

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  • Oracle VM Templates for EBS 12.1.3 for Exalogic Now Available

    - by Elke Phelps (Oracle Development)
    Oracle VM Templates for Oracle E-Business Suite 12.1.3 for x86 Exalogic Platform (64 bit) are now available on the Oracle Software Delivery Cloud.  The templates contain all the required elements to create an Oracle E-Business Suite R12 demonstration system on an Exalogic server. You can use these templates to quickly build an EBS 12.1.3 demonstration environment, bypassing the operating system and the software install (via the EBS Rapid Install).   The Oracle E-Business Suite Release 12.1.3 (64 bit) template for the Exalogic platform is a Oracle Virtual Server Guest template that contains a complete Oracle E-Business Suite Release 12.1.3 Database Tier and Application Tier Installation.  For additional details, please refer to the following My Oracle Support Note: Oracle E-Business Suite Release 12.1.3 Database Tier and Application Tier Template for Oracle Exalogic Platform (Note 1499132.1) The Oracle E-Business Suite system is installed on top of Oracle Linux Version 5 update 6. The templates have been optimized for performance, including OS kernel settings and E-Business Suite configuration settings tuned specifically for the Exalogic platform.  The configuration delivered with this template for a mid-tier running on Exalogic will support hundreds of concurrent users.  Please refer to Section 2: Performance Analysis in My Oracle Support Note 1499132.1 for additional details.   Additional Information The Oracle E-Business Suite VM templates for the Exalogic platform contain the following software versions: Operating System: Oracle Linux Version 5 Update 6 Oracle E-Business Suite 12.1.3 (Database Tier) Oracle E-Business Suite 12.1.3 (Application Tier) The following considerations were made when the Oracle E-Business Suite VM template for the Exalogic platform were designed: Templates use the hardware-virtualized architecture, supporting hardware with virtualization feature. Database Tier Template is configured to use the following configuration: 16 GB RAM 4 VCPUs 250 GB of Disk space for application installation Application Tier Template is configured to use the following configuration: 16 GB RAM 4 VCPUs 50 GB of Disk space for application installation References Oracle E-Business Suite Release 12.1.3 Database Tier and Application Tier Template for Oracle Exalogic Platform (Note 1499132.1) Related Articles Part 1: E-Business Suite 12.1.1 Templates for Oracle VM Now Available Part 2: Using Oracle VM with Oracle E-Business Suite Virtualization Kit Part 3: On Clouds and Virtualization in EBS Environments (OpenWorld 2009 Recap) Part 4: Deploying E-Business Suite on Amazon Web Services Elastic Compute Cloud Part 5: Live Migration of EBS Services Using Oracle VM Support Policies for Virtualization Technologies and Oracle E-Business Suite Virtualization and the E-Business Suite, Redux Virtualization and E-Business Suite

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  • SQL SERVER – Core Concepts – Elasticity, Scalability and ACID Properties – Exploring NuoDB an Elastically Scalable Database System

    - by pinaldave
    I have been recently exploring Elasticity and Scalability attributes of databases. You can see that in my earlier blog posts about NuoDB where I wanted to look at Elasticity and Scalability concepts. The concepts are very interesting, and intriguing as well. I have discussed these concepts with my friend Joyti M and together we have come up with this interesting read. The goal of this article is to answer following simple questions What is Elasticity? What is Scalability? How ACID properties vary from NOSQL Concepts? What are the prevailing problems in the current database system architectures? Why is NuoDB  an innovative and welcome change in database paradigm? Elasticity This word’s original form is used in many different ways and honestly it does do a decent job in holding things together over the years as a person grows and contracts. Within the tech world, and specifically related to software systems (database, application servers), it has come to mean a few things - allow stretching of resources without reaching the breaking point (on demand). What are resources in this context? Resources are the usual suspects – RAM/CPU/IO/Bandwidth in the form of a container (a process or bunch of processes combined as modules). When it is about increasing resources the simplest idea which comes to mind is the addition of another container. Another container means adding a brand new physical node. When it is about adding a new node there are two questions which comes to mind. 1) Can we add another node to our software system? 2) If yes, does adding new node cause downtime for the system? Let us assume we have added new node, let us see what the new needs of the system are when a new node is added. Balancing incoming requests to multiple nodes Synchronization of a shared state across multiple nodes Identification of “downstate” and resolution action to bring it to “upstate” Well, adding a new node has its advantages as well. Here are few of the positive points Throughput can increase nearly horizontally across the node throughout the system Response times of application will increase as in-between layer interactions will be improved Now, Let us put the above concepts in the perspective of a Database. When we mention the term “running out of resources” or “application is bound to resources” the resources can be CPU, Memory or Bandwidth. The regular approach to “gain scalability” in the database is to look around for bottlenecks and increase the bottlenecked resource. When we have memory as a bottleneck we look at the data buffers, locks, query plans or indexes. After a point even this is not enough as there needs to be an efficient way of managing such large workload on a “single machine” across memory and CPU bound (right kind of scheduling)  workload. We next move on to either read/write separation of the workload or functionality-based sharing so that we still have control of the individual. But this requires lots of planning and change in client systems in terms of knowing where to go/update/read and for reporting applications to “aggregate the data” in an intelligent way. What we ideally need is an intelligent layer which allows us to do these things without us getting into managing, monitoring and distributing the workload. Scalability In the context of database/applications, scalability means three main things Ability to handle normal loads without pressure E.g. X users at the Y utilization of resources (CPU, Memory, Bandwidth) on the Z kind of hardware (4 processor, 32 GB machine with 15000 RPM SATA drives and 1 GHz Network switch) with T throughput Ability to scale up to expected peak load which is greater than normal load with acceptable response times Ability to provide acceptable response times across the system E.g. Response time in S milliseconds (or agreed upon unit of measure) – 90% of the time The Issue – Need of Scale In normal cases one can plan for the load testing to test out normal, peak, and stress scenarios to ensure specific hardware meets the needs. With help from Hardware and Software partners and best practices, bottlenecks can be identified and requisite resources added to the system. Unfortunately this vertical scale is expensive and difficult to achieve and most of the operational people need the ability to scale horizontally. This helps in getting better throughput as there are physical limits in terms of adding resources (Memory, CPU, Bandwidth and Storage) indefinitely. Today we have different options to achieve scalability: Read & Write Separation The idea here is to do actual writes to one store and configure slaves receiving the latest data with acceptable delays. Slaves can be used for balancing out reads. We can also explore functional separation or sharing as well. We can separate data operations by a specific identifier (e.g. region, year, month) and consolidate it for reporting purposes. For functional separation the major disadvantage is when schema changes or workload pattern changes. As the requirement grows one still needs to deal with scale need in manual ways by providing an abstraction in the middle tier code. Using NOSQL solutions The idea is to flatten out the structures in general to keep all values which are retrieved together at the same store and provide flexible schema. The issue with the stores is that they are compromising on mostly consistency (no ACID guarantees) and one has to use NON-SQL dialect to work with the store. The other major issue is about education with NOSQL solutions. Would one really want to make these compromises on the ability to connect and retrieve in simple SQL manner and learn other skill sets? Or for that matter give up on ACID guarantee and start dealing with consistency issues? Hybrid Deployment – Mac, Linux, Cloud, and Windows One of the challenges today that we see across On-premise vs Cloud infrastructure is a difference in abilities. Take for example SQL Azure – it is wonderful in its concepts of throttling (as it is shared deployment) of resources and ability to scale using federation. However, the same abilities are not available on premise. This is not a mistake, mind you – but a compromise of the sweet spot of workloads, customer requirements and operational SLAs which can be supported by the team. In today’s world it is imperative that databases are available across operating systems – which are a commodity and used by developers of all hues. An Ideal Database Ability List A system which allows a linear scale of the system (increase in throughput with reasonable response time) with the addition of resources A system which does not compromise on the ACID guarantees and require developers to learn new paradigms A system which does not force fit a new way interacting with database by learning Non-SQL dialect A system which does not force fit its mechanisms for providing availability across its various modules. Well NuoDB is the first database which has all of the above abilities and much more. In future articles I will cover my hands-on experience with it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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  • How to fix v4l2 Input/output error, vostro 1510 ubuntu 13.04 64bits?

    - by Fabio C. Barrionuevo da Luz
    I clean install upgrade to ubuntu 13.04 64btis, but the cheese and simplecv are no longer functioning properly. In previous versions of Ubuntu, everything worked normally. By running the two programs, I get the following message: libv4l2: error turning on stream: Input/output error ps: sorry, my English is very ugly. full hardware description of my notebook on this link: https://gist.github.com/luzfcb/5873728

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  • Adobe Flash Player fails

    - by David Cole
    Using UBUNTU 11.10 the FireFox error message says "A plugin is needed to display this content: Adobe Flash Player Installer" So I install it. Then it says "Installed - restart FireFox" I restart FireFox and the same error message appears. This problem doesn't happen with Windows 7 (IE, Chrome & Firefox are fine) or my previous version of Ubuntu. Problem occurs when I access CallOfRoma.com Thank You

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  • Is hashing of just "username + password" as safe as salted hashing

    - by randomA
    I want to hash "user + password". EDIT: prehashing "user" would be an improvement, so my question is also for hashing "hash(user) + password". If cross-site same user is a problem then the hashing changed to hashing "hash(serviceName + user) + password" From what I read about salted hash, using "user + password" as input to hash function will help us avoid problem with reverse hash table hacking. The same thing can be said about rainbow table. Any reason why this is not as good as salted hashing?

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  • Troubleshooting an unstable internet connection

    - by Konrad Rudolph
    My MacBook Pro running OS X (10.9, but I had the same problem before) is connected to a Belkin router via WiFi and, using Virgin Media as the ISP, to the internet. The connection is extremely unstable – on some days, I get a ping timeout every few seconds. In addition, some domains seem to suffer general connectivity issues. For instance, I often find that while the youtube.com website loads, none of the videos (which are hosted on a separate domain) do. At other times, videos load but always fail to buffer, even though the actual connection speed is ok, even though I’ve disabled dash playback. Since I’m living in a rented room and the ISP contract isn’t actually mine I’ve got only limited possibilities of addressing the problem. In particular, I have no access to the router configuration and my non tech savvy landlady, while sympathetic, is not in a great hurry to hand the problem over to the ISP’s customer support. What’s more, I seem to be the only person in the house experiencing these problems – but I can imagine that this is simply because I’m the only one who’s using the internet continuously. I’m searching for specific tests that might be able to pinpoint – and ideally solve – the problem. So far all I’ve managed to do is establish that Virgin is routing my traffic in mysterious ways. Here’s an excerpt from traceroute google.co.uk. It’s worth mentioning that the host name doesn’t seem to matter a lot, the trace route is always the same. traceroute: Warning: google.co.uk has multiple addresses; using 62.254.36.148 traceroute to google.co.uk (62.254.36.148), 64 hops max, 52 byte packets 1 (192.168.2.1) 1.112 ms 1.300 ms 2.359 ms 2 10.100.32.1 (10.100.32.1) 11.926 ms 10.217 ms 24.987 ms 3 cmbg-core-1a-ae3-610.network.virginmedia.net (80.1.202.93) 28.809 ms * 66.653 ms 4 popl-bb-1b-ae16-0.network.virginmedia.net (212.43.163.141) 13.759 ms 126.504 ms 20.472 ms 5 nrth-bb-1b-et-010-0.network.virginmedia.net (62.253.175.57) 28.357 ms 16.398 ms 42.387 ms 6 nrth-bb-1c-ae1-0.network.virginmedia.net (62.253.174.110) 27.441 ms 15.622 ms 12.044 ms 7 lutn-icdn-1-ae0-0.network.virginmedia.net (62.253.175.82) 16.678 ms 28.463 ms 28.253 ms 8 * * * 9 * * * 10 * * * ^C If I let it, this goes on until the end of time. It never seems to reach a destination. Is this normal? A friend living in the same town who is also with Virgin Media has a more conventional traceroute output: 7 hops to google.co.uk, all of which send the ICMP TIME_EXCEEDED response. The obvious fix – rebooting the router – doesn’t seem to help. As far as I can tell, the WiFi connection is stable (I can always ping the router) so the problem is further downstream. I’ve tried using an alternative DNS before (OpenDNS) but if anything, this made things worse. In fact, it made all Google services nigh unreachable.

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  • U Central Florida Streamlines Administrative Apps

    - by jay.richey
    The University of Central Florida is wrapping up a multi-year implementation of new enterprise applications that includes a combination of Oracle software and Sun hardware to streamline its administrative processes and help manage student growth. The Orlando-based university currently has more than 56,000 students, making it the second largest American university by enrollment, behind only Arizona State University, which has more than 70,400 students. Read more...

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  • Network Balancing Act

    - by listey
    Next up in our popular Oracle Solaris How To series is the Integrated Load Balancer, part of the suite of network facilities that are built in to Oracle Solaris 11. Providing Layer 3 and Layer 4 load balancing capabilities you can use this device to simulate or even replace your hardware based network infrastructure. Read more about the capabilities and how to get a basic configuration working in How to Set Up a Load-Balanced Application Across Two Oracle Solaris Zones

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  • Adobe Reader crashes immediately after starting

    - by Tanveer Hossain
    I'm running ubuntu 12.04 32 bit system. I installed adobe reader through software center but when click on the icon to start acroread it immediately crashes during showing splash window. I've also tried using terminal running command "acroread" but no gain. It even doesn't show any error massage. It should be noted that to solve the problem i've installed lsb module and ia32-libs. But my problem is not solved.

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