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  • snmp and platform specific information

    - by reza
    I need to come with a strategy to use gather information about the health of my linux platform, hardware health such as high CPU temperature and may be disk space usage, etc... I know my examples are not very good ones. Essentially, I have an SNMP agent running on Linux and I need it to provide platform specific health and state information. Are there any Linux packages that do this, what MIBs to use, Dell Open Manager functionality??? Any thoughts and comments are appreciated.

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  • Error on MulticastSocket.joinGroup()

    - by Pedro Ghilardi
    I'm trying to execute a simple example of Multicast sockets on Java. MulticastSocket s = new MulticastSocket(6789); InetAddress group = InetAddress.getByName("230.1.1.1"); s.joinGroup(group); This code generates the error: IP_ADD_MEMBERSHIP failed (out of hardware filters?) Any idea? Thanks

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  • How compliant is SIP VoIP software on the net?

    - by rusbi
    I developed a SIP stack for my company. It's far from perfect, a it's lacking a lot of things from the RFCs, but it's functional and work well with a lot of tested softphones and other SIP hardware and software. My question is: How much of SIP software can truly say that they are entirely SIP compliant? (Of the softphones you can find on the internet...)

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  • dlopen and global variables in C/C++

    - by mjn12
    Due to some restrictions I am being forced to load a library written in C at runtime. A third party provides two library to me as static archives which we turn into shared objects. The application I'm working with loads one of the libraries at runtime based on some hardware parameters. Unfortunately one of the libraries is configured largely with global variables. I am already using dlsym to load function references but can I used dlsym to load references to these global variables as well?

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  • WebSphere hung threads, how can I track then down?

    - by Puzzled
    We have an application running on WebSphere (unfortunately it is 6.1 which is no longer supported, it has not yet been migrated in production to a later version) which becomes entirely unresponsive because of hung threads. As far as I can tell we entirely exhaust one of the thread pools. I have activated hung thread detection and I get a core/thread dump when hung threads are detected. The server can run for several days without problems but has crashed twice this week. When load the core/thread dump in "IBM Thread and Monitor Dump Analyzer for Java", it tells me that there are a certain number of hung threads (this time it was 2, last time 11) and multiple (usually around 40) threads "waiting on condition" and some running threads. I believe one of the thread pool has around that size (50). Now what I see in there are threads waiting for locks, having locks or in wait. Most of them show a stack track which always ends like this: at java/lang/Object.wait(Native Method) at java/lang/Object.wait(Object.java:231) Now, how can I track this down to either a server configuration problem, application issue, WebSphere problem or something else? How is this supposed to help me track down the problem when almost everything in there refers to IBM code? I cannot ask IBM's help as 6.1 is now an unsupported version of WebSphere and while work has been done to make it work under WebSphere 7 we are not yet ready to switch to it in Production yet.

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  • Forcing driver to device match

    - by shodanex
    I have a piece of usb hardware, for which I know the driver. However, the vendor id and product id do not match the VID, PID pair registered in the driver. Is there a way in linux to force a driver to be associated with a known device, that do not involve kernel module recompilation to add a PID / VID pair ?

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  • how to calculate power consumption on an Android mobile that uses wifi?

    - by Marco
    Hello, I have implemented a routing protocol on an Android 1.6 mobile that uses wireless (ad-hoc) network in order to exchange messages. Now I would like to evaluate it under an energy consumption point of view, the base would be to try to calculate the energy wasted to transmit a single packet, do anybody has any idea how to do that? Software/hardware solutions are welcome! Thanx :)

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  • Any tips for how to build a LED system thet will light up to music?

    - by daniels
    So basically I would like somehow that given an audio file as input (most likely mp3 or I can use some audio engine that will handle other types too) from my computer to control some LED lights so they will be something like an oscilloscope, like the one in winamp. What would I need to be able to do this? I'm interested in building thing up all by myself, coding, hardware, etc.. I'm going with C++ on Windows.

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  • Why should you choose Oracle WebLogic 12c instead of JBoss EAP 6?

    - by Ricardo Ferreira
    In this post, I will cover some technical differences between Oracle WebLogic 12c and JBoss EAP 6, which was released a couple days ago from Red Hat. This article claims to help you in the evaluation of key points that you should consider when choosing for an Java EE application server. In the following sections, I will present to you some important aspects that most customers ask us when they are seriously evaluating for an middleware infrastructure, specially if you are considering JBoss for some reason. I would suggest that you keep the following question in mind while you are reading the points: "Why should I choose JBoss instead of WebLogic?" 1) Multi Datacenter Deployment and Clustering - D/R ("Disaster & Recovery") architecture support is embedded on the WebLogic Server 12c product. JBoss EAP 6 on the other hand has no direct D/R support included, Red Hat relies on third-part tools with higher prices. When you consider a middleware solution to host your business critical application, you should worry with every architectural aspect that are related with the solution. Fail-over support is one little aspect of a truly reliable solution. If you do not worry about D/R, your solution will not be reliable. Having said that, with Red Hat and JBoss EAP 6, you have this extra cost that will increase considerably the total cost of ownership of the solution. As we commonly hear from analysts, open-source are not so cheaper when you start seeing the big picture. - WebLogic Server 12c supports advanced LAN clustering, detection of death servers and have a common alert framework. JBoss EAP 6 on the other hand has limited LAN clustering support with no server death detection. They do not generate any alerts when servers goes down (only if you buy JBoss ON which is a separated technology, but until now does not support JBoss EAP 6) and manual intervention are required when servers goes down. In most cases, admin people must rely on "kill -9", "tail -f someFile.log" and "ps ax | grep java" commands to manage failures and clustering anomalies. - WebLogic Server 12c supports the concept of Node Manager, which is a separated process that runs on the physical | virtual servers that allows extend the administration of the cluster to WebLogic managed servers that are often distributed across multiple machines and geographic locations. JBoss EAP 6 on the other hand has no equivalent technology. Whole server instances must be managed individually. - WebLogic Server 12c Node Manager supports Coherence to boost performance when managing servers. JBoss EAP 6 on the other hand has no similar technology. There is no way to coordinate JBoss and infiniband instances provided by JBoss using high throughput and low latency protocols like InfiniBand. The Node Manager feature also allows another very important feature that JBoss EAP lacks: secure the administration. When using WebLogic Node Manager, all the administration tasks are sent to the managed servers in a secure tunel protected by a certificate, which means that the transport layer that separates the WebLogic administration console from the managed servers are secured by SSL. - WebLogic Server 12c are now integrated with OTD ("Oracle Traffic Director") which is a web server technology derived from the former Sun iPlanet Web Server. This software complements the web server support offered by OHS ("Oracle HTTP Server"). Using OTD, WebLogic instances are load-balanced by a high powerful software that knows how to handle SDP ("Socket Direct Protocol") over InfiniBand, which boost performance when used with engineered systems technologies like Oracle Exalogic Elastic Cloud. JBoss EAP 6 on the other hand only offers support to Apache Web Server with custom modules created to deal with JBoss clusters, but only across standard TCP/IP networks.  2) Application and Runtime Diagnostics - WebLogic Server 12c have diagnostics capabilities embedded on the server called WLDF ("WebLogic Diagnostic Framework") so there is no need to rely on third-part tools. JBoss EAP 6 on the other hand has no diagnostics capabilities. Their only diagnostics tool is the log generated by the application server. Admin people are encouraged to analyse thousands of log lines to find out what is going on. - WebLogic Server 12c complement WLDF with JRockit MC ("Mission Control"), which provides to administrators and developers a complete insight about the JVM performance, behavior and possible bottlenecks. WebLogic Server 12c also have an classloader analysis tool embedded, and even a log analyzer tool that enables administrators and developers to view logs of multiple servers at the same time. JBoss EAP 6 on the other hand relies on third-part tools to do something similar. Again, only log searching are offered to find out whats going on. - WebLogic Server 12c offers end-to-end traceability and monitoring available through Oracle EM ("Enterprise Manager"), including monitoring of business transactions that flows through web servers, ESBs, application servers and database servers, all of this with high deep JVM analysis and diagnostics. JBoss EAP 6 on the other hand, even using JBoss ON ("Operations Network"), which is a separated technology, does not support those features. Red Hat relies on third-part tools to provide direct Oracle database traceability across JVMs. One of those tools are Oracle EM for non-Oracle middleware that manage JBoss, Tomcat, Websphere and IIS transparently. - WebLogic Server 12c with their JRockit support offers a tool called JRockit Flight Recorder, which can give developers a complete visibility of a certain period of application production monitoring with zero extra overhead. This automatic recording allows you to deep analyse threads latency, memory leaks, thread contention, resource utilization, stack overflow damages and GC ("Garbage Collection") cycles, to observe in real time stop-the-world phenomenons, generational, reference count and parallel collects and mutator threads analysis. JBoss EAP 6 don't even dream to support something similar, even because they don't have their own JVM. 3) Application Server Administration - WebLogic Server 12c offers a complete administration console complemented with scripting and macro-like recording capabilities. A single WebLogic console can managed up to hundreds of WebLogic servers belonging to the same domain. JBoss EAP 6 on the other hand has a limited console and provides a XML centric administration. JBoss, after ten years, started the development of a rudimentary centralized administration that still leave a lot of administration tasks aside, so admin people and developers must touch scripts and XML configuration files for most advanced and even simple administration tasks. This lead applications to error prone and risky deployments. Even using JBoss ON, JBoss EAP are not able to offer decent administration features for admin people which must be high skilled in JBoss internal architecture and its managing capabilities. - Oracle EM is available to manage multiple domains, databases, application servers, operating systems and virtualization, with a complete end-to-end visibility. JBoss ON does not provide management capabilities across the complete architecture, only basic monitoring. Even deployment must be done aside JBoss ON which does no integrate well with others softwares than JBoss. Until now, JBoss ON does not supports JBoss EAP 6, so even their minimal support for JBoss are not available for JBoss EAP 6 leaving customers uncovered and subject to high skilled JBoss admin people. - WebLogic Server 12c has the same administration model whatever is the topology selected by the customer. JBoss EAP 6 on the other hand differentiates between two operational models: standalone-mode and domain-mode, that are not consistent with each other. Depending on the mode used, the administration skill is different. - WebLogic Server 12c has no point-of-failures processes, and it does not need to define any specialized server. Domain model in WebLogic is available for years (at least ten years or more) and is production proven. JBoss EAP 6 on the other hand needs special processes to garantee JBoss integrity, the PC ("Process-Controller") and the HC ("Host-Controller"). Different from WebLogic, the domain model in JBoss is quite new (one year at tops) of maturity, and need to mature considerably until start doing things like WebLogic domain model does. - WebLogic Server 12c supports parallel deployment model which enables some artifacts being deployed at the same time. JBoss EAP 6 on the other hand does not have any similar feature. Every deployment are done atomically in the containers. This means that if you have a huge EAR (an EAR of 120 MB of size for instance) and deploy onto JBoss EAP 6, this EAR will take some minutes in order to starting accept thread requests. The same EAR deployed onto WebLogic Server 12c will reduce the deployment time at least in 2X compared to JBoss. 4) Support and Upgrades - WebLogic Server 12c has patch management available. JBoss EAP 6 on the other hand has no patch management available, each JBoss EAP instance should be patched manually. To achieve such feature, you need to buy a separated technology called JBoss ON ("Operations Network") that manage this type of stuff. But until now, JBoss ON does not support JBoss EAP 6 so, in practice, JBoss EAP 6 does not have this feature. - WebLogic Server 12c supports previuous WebLogic domains without any reconfiguration since its kernel is robust and mature since its creation in 1995. JBoss EAP 6 on the other hand has a proven lack of supportability between JBoss AS 4, 5, 6 and 7. Different kernels and messaging engines were implemented in JBoss stack in the last five years reveling their incapacity to create a well architected and proven middleware technology. - WebLogic Server 12c has patch prescription based on customer configuration. JBoss EAP 6 on the other hand has no such capability. People need to create ticket supports and have their installations revised by Red Hat support guys to gain some patch prescription from them. - Oracle WebLogic Server independent of the version has 8 years of support of new patches and has lifetime release of existing patches beyond that. JBoss EAP 6 on the other hand provides patches for a specific application server version up to 5 years after the release date. JBoss EAP 4 and previous versions had only 4 years. A good question that Red Hat will argue to answer is: "what happens when you find issues after year 5"?  5) RAC ("Real Application Clusters") Support - WebLogic Server 12c ships with a specific JDBC driver to leverage Oracle RAC clustering capabilities (Fast-Application-Notification, Transaction Affinity, Fast-Connection-Failover, etc). Oracle JDBC thin driver are also available. JBoss EAP 6 on the other hand ships only the standard Oracle JDBC thin driver. Load balancing with Oracle RAC are not supported. Manual intervention in case of planned or unplanned RAC downtime are necessary. In JBoss EAP 6, situation does not reestablish automatically after downtime. - WebLogic Server 12c has a feature called Active GridLink for Oracle RAC which provides up to 3X performance on OLTP applications. This seamless integration between WebLogic and Oracle database enable more value added to critical business applications leveraging their investments in Oracle database technology and Oracle middleware. JBoss EAP 6 on the other hand has no performance gains at all, even when admin people implement some kind of connection-pooling tuning. - WebLogic Server 12c also supports transaction and web session affinity to the Oracle RAC, which provides aditional gains of performance. This is particularly interesting if you are creating a reliable solution that are distributed not only in an LAN cluster, but into a different data center. JBoss EAP 6 on the other hand has no such support. 6) Standards and Technology Support - WebLogic Server 12c is fully Java EE 6 compatible and production ready since december of 2011. JBoss EAP 6 on the other hand became fully compatible with Java EE 6 only in the community version after three months, and production ready only in a few days considering that this article was written in June of 2012. Red Hat says that they are the masters of innovation and technology proliferation, but compared with Oracle and even other proprietary vendors like IBM, they historically speaking are lazy to deliver the most newest technologies and standards adherence. - Oracle is the steward of Java, driving innovation into the platform from commercial and open-source vendors. Red Hat on the other hand does not have its own JVM and relies on third-part JVMs to complete their application server offer. 95% of Red Hat customers are using Oracle HotSpot as JVM, which means that without Oracle involvement, their support are limited exclusively to the application server layer and we all know that most problems are happens in the JVM layer. - WebLogic Server 12c supports natively JDK 7, which empower developers to explore the maximum of the Java platform productivity when writing code. This feature differentiate WebLogic from others application servers (except GlassFish that are also managed by Oracle) because the usage of JDK 7 introduce such remarkable productivity features like the "try-with-resources" enhancement, catching multiple exceptions with one try block, Strings in the switch statements, JVM improvements in terms of JDBC, I/O, networking, security, concurrency and of course, the most important feature of Java 7: native support for multiple non-Java languages. More features regarding JDK 7 can be found here. JBoss EAP 6 on the other hand does not support JDK 7 officially, they comment in their community version that "Java SE 7 can be used with JBoss 7" which does not gives you any guarantees of enterprise support for JDK 7. - Oracle WebLogic Server 12c supports integration with Spring framework allowing Spring applications to use WebLogic special transaction manager, exposing bean interfaces to WebLogic MBeans to take advantage of all WebLogic monitoring and administration advantages. JBoss EAP 6 on the other hand has no special integration with Spring. In fact, Red Hat offers a suspicious package called "JBoss Web Platform" that in theory supports Spring, but in practice this package does not offers any special integration. It is just a facility for Red Hat customers to have support from both JBoss and Spring technology using the same customer support. 7) Lightweight Development - Oracle WebLogic Server 12c and Oracle GlassFish are completely integrated and can share applications without any modifications. Starting with the 12c version, WebLogic now understands natively GlassFish deployment descriptors and specific configurations in order to offer you a truly and reliable migration path from a community Java EE application server to a enterprise middleware product like WebLogic. JBoss EAP 6 on the other hand has no support to natively reuse an existing (or still in development) application from JBoss AS community server. Users of JBoss suffer of critical issues during deployment time that includes: changing the libraries and dependencies of the application, patching the DTD or XSD deployment descriptors, refactoring of the application layers due classloading issues and anomalies, rebuilding of persistence, business and web layers due issues with "usage of the certified version of an certain dependency" or "frameworks that Red Hat potentially does not recommend" etc. If you have the culture or enterprise IT directive of developing Java EE applications using community middleware to in a certain future, transition to enterprise (supported by a vendor) middleware, Oracle WebLogic plus Oracle GlassFish offers you a more sustainable solution. - WebLogic Server 12c has a very light ZIP distribution (less than 165 MB). JBoss EAP 6 ZIP size is around 130 MB, together with JBoss ON you have more 100 MB resulting in a higher download footprint. This is particularly interesting if you plan to use automated setup of application server instances (for example, to rapidly setup a development or staging environment) using Maven or Hudson. - WebLogic Server 12c has a complete integration with Maven allowing developers to setup WebLogic domains with few commands. Tasks like downloading WebLogic, installation, domain creation, data sources deployment are completely integrated. JBoss EAP 6 on the other hand has a limited offer integration with those tools.  - WebLogic Server 12c has a startup mode called WLX that turns-off EJB, JMS and JCA containers leaving enabled only the web container with Java EE 6 web profile. JBoss EAP 6 on the other hand has no such feature, you need to disable manually the containers that you do not want to use. - WebLogic Server 12c supports fastswap, which enables you to change classes without redeployment. This is particularly interesting if you are developing patches for the application that is already deployed and you do not want to redeploy the entire application. This is the same behavior that most application servers offers to JSP pages, but with WebLogic Server 12c, you have the same feature for Java classes in general. JBoss EAP 6 on the other hand has no such support. Even JBoss EAP 5 does not support this until now. 8) JMS and Messaging - WebLogic Server 12c has a proven and high scalable JMS implementation since its initial release in 1995. JBoss EAP 6 on the other hand has a still immature technology called HornetQ, which was introduced in JBoss EAP 5 replacing everything that was implemented in the previous versions. Red Hat loves to introduce new technologies across JBoss versions, playing around with customers and their investments. And when they are asked about why they have changed the implementation and caused such a mess, their answer is always: "the previous implementation was inadequate and not aligned with the community strategy so we are creating a new a improved one". This Red Hat practice leads to uncomfortable investments that in a near future (sometimes less than a year) will be affected in someway. - WebLogic Server 12c has troubleshooting and monitoring features included on the WebLogic console and WLDF. JBoss EAP 6 on the other hand has no direct monitoring on the console, activity is reflected only on the logs, no debug logs available in case of JMS issues. - WebLogic Server 12c has extremely good performance and scalability. JBoss EAP 6 on the other hand has a JMS storage mechanism relying on Oracle database or MySQL. This means that if an issue in production happens and Red Hat affirms that an performance issue is happening due to database problems, they will not support you on the performance issue. They will orient you to call Oracle instead. - WebLogic Server 12c supports messaging enterprise features like SAF ("Store and Forward"), Distributed Queues/Topics and Foreign JMS providers support that leverage JMS implementations without compromise developer code making things completely transparent. JBoss EAP 6 on the other hand do not even dream to support such features. 9) Caching and Grid - Coherence, which is the leading and most mature data grid technology from Oracle, is available since early 2000 and was integrated with WebLogic in 2009. Coherence and WebLogic clusters can be both managed from WebLogic administrative console. Even Node Manager supports Coherence. JBoss on the other hand discontinued JBoss Cache, which was their caching implementation just like they did with the messaging implementation (JBossMQ) which was a issue for long term customers. JBoss EAP 6 ships InfiniSpan version 1.0 which is immature and lack a proven record of successful cases and reliability. - WebLogic Server 12c has a feature called ActiveCache which uses Coherence to, without any code changes, replicate HTTP sessions from both WebLogic and other application servers like JBoss, Tomcat, Websphere, GlassFish and even Microsoft IIS. JBoss EAP 6 on the other hand does have such support and even when they do in the future, they probably will support only their own application server. - Coherence can be used to manage both L1 and L2 cache levels, providing support to Oracle TopLink and others JPA compliant implementations, even Hibernate. JBoss EAP 6 and Infinispan on the other hand supports only Hibernate. And most important of all: Infinispan does not have any successful case of L1 or L2 caching level support using Hibernate, which lead us to reflect about its viability. 10) Performance - WebLogic Server 12c is certified with Oracle Exalogic Elastic Cloud and can run unchanged applications at this engineered system. This approach can benefit customers from Exalogic optimization's of both kernel and JVM layers to boost performance in terms of 10X for web, OLTP, JMS and grid applications. JBoss EAP 6 on the other hand has no investment on engineered systems: customers do not have the choice to deploy on a Java ultra fast system if their project becomes relevant and performance issues are detected. - WebLogic Server 12c maintains a performance gain across each new release: starting on WebLogic 5.1, the overall performance gain has been close to 4X, which close to a 20% gain release by release. JBoss on the other hand does not provide SPECJAppServer or SPECJEnterprise performance benchmarks. Their so called "performance gains" remains hidden in their customer environments, which lead us to think if it is true or not since we will never get access to those environments. - WebLogic Server 12c has industry performance benchmarks with submissions across platforms and configurations leading SPECJ. Oracle WebLogic leads SPECJAppServer performance in multiple categories, fitting all customer topologies like: dual-node, single-node, multi-node and multi-node with RAC. JBoss... again, does not provide any SPECJAppServer performance benchmarks. - WebLogic Server 12c has a feature called work manager which allows your application to embrace new performance levels based on critical resource utilization of the CPUs usage. Work managers prioritizes work and allocates threads based on an execution model that takes into account administrator-defined parameters and actual run-time performance and throughput. JBoss EAP 6 on the other hand has no compared feature and probably they never will. Not supporting such feature like work managers, JBoss EAP 6 forces admin people and specially developers to uncover performance gains in a intrusive way, rewriting the code and doing performance refactorings. 11) Professional Services Support - WebLogic Server 12c and any other technology sold by Oracle give customers the possibility of hire OCS ("Oracle Consulting Services") to manage critical scenarios, deployment assistance of new applications, high skilled consultancy of architecture, best practices and people allocation together with customer teams. All OCS services are available without any restrictions, having the customer bought software from Oracle or just starting their implementation before any acquisition. JBoss EAP 6 or Red Hat to be more specifically, only offers professional services if you buy subscriptions from them. If you are developing a new critical application for your business and need the help of Red Hat for a serious issue or architecture decision, they will probably say: "OK... I can help you but after you buy subscriptions from me". Red Hat also does not allows their professional services consultants to manage environments that uses community based software. They will probably force you to first buy a subscription, download their "enterprise" version and them, optionally hire their consultants. - Oracle provides you our university to educate your team into our technologies, including of course specialized trainings of WebLogic application server. At any time and location, you can hire Oracle to train your team so you get trustful knowledge according to your specific needs. Certifications for the products are also available if your technical people desire to differentiate themselves as professionals. Red Hat on the other hand have a limited pool of resources to train your team in their technologies. Basically they are selling training and certification for RHEL ("Red Hat Enterprise Linux") but if you demand more specialized training in JBoss middleware, they will probably connect you to some "certified" partner localized training since they are apparently discontinuing their education center, at least here in Brazil. They were not able to reproduce their success with RHEL education to their middleware division since they need first sell the subscriptions to after gives you specialized training. And again, they only offer you specialized training based on their enterprise version (EAP in the case of JBoss) which means that the courses will be a quite outdated. There are reports of developers that took official training's from Red Hat at this year (2012) and in a certain JBoss advanced course, Red Hat supposedly covered JBossMQ as the messaging subsystem, and even the printed material provided was based on JBossMQ since the training was created for JBoss EAP 4.3. 12) Encouraging Transparency without Ulterior Motives - WebLogic Server 12c like any other software from Oracle can be downloaded any time from anywhere, you should only possess an OTN ("Oracle Technology Network") credential and you can download any enterprise software how many times you want. And is not some kind of "trial" version. It is the official binaries that will be running for ever in your data center. Oracle does not encourages the usage of "specific versions" of our software. The binaries you buy from Oracle are the same binaries anyone in the world could download and use for testing and personal education. JBoss EAP 6 on the other hand are not available for download unless you buy a subscription and get access to the Red Hat enterprise repositories. If you need to test, learn or just start creating your application using Red Hat's middleware software, you should download it from the community website. You are not allowed to download the enterprise version that, according to Red Hat are more secure, reliable and robust. But no one of us want to start the development of a software with an unsecured, unreliable and not scalable middleware right? So what you do? You are "invited" by Red Hat to buy subscriptions from them to get access to the "cool" version of the software. - WebLogic Server 12c prices are publicly available in the Oracle website. If you want to know right now how much WebLogic will cost to your organization, just click here and get access to our price list. In the case of WebLogic, check out the "US Oracle Technology Commercial Price List". Oracle also encourages you to get in touch with a sales representative to discuss discounts that would make possible the investment into our technology. But you are not required to do this, only if you are interested in buying our technology or maybe you want to discuss some discount scenarios. JBoss EAP 6 on the other hand does not have its cost publicly available in Red Hat's website or in any other media, at least is not so easy to get such information. The only link you will possibly find in their website is a "Contact a Sales Representative" link. This is not a very good relationship between an customer and an vendor. This is not an example of transparency, mainly when the software are sold as open. In this situations, customers expects to see the software prices publicly available, so they can have the chance to decide, based on the existing features of the software, if the cost is fair or not. Conclusion Oracle WebLogic is the most mature, secure, reliable and scalable Java EE application server of the market, and have a proven record of success around the globe to prove it's majority. Don't lose the chance to discover today how WebLogic could fit your needs and sustain your global IT middleware strategy, no matter if your strategy are completely based on the Cloud or not.

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  • Bypass BIOS password set by faulty Toshiba firmware on Satellite A55 laptop?

    - by Brian
    How can the CMOS be cleared on the Toshiba Satellite A55-S1065? I have this 7 year old laptop that has been crippled by a glitch in its BIOS: 'A "Password =" prompt may be displayed when the computer is turned on, even though no power-on password has been set. If this happens, there is no password that will satisfy the password request. The computer will be unusable until this problem is resolved. [..] The occurrence of this problem on any particular computer is unpredictable -- it may never happen, but it could happen any time that the computer is turned on. [..] Toshiba will cover the cost of this repair under warranty until Dec 31, 2010.' -Toshiba As they stated, this machine is "unusable." The escape key does not bypass the prompt (nor does any other key), thus no operating system can be booted and no firmware updates can be installed. After doing some research, I found solutions that have been suggested for various Toshiba Satellite models afflicted by this glitch: "Make arrangements with a Toshiba Authorized Service Provider to have this problem resolved." -Toshiba (same link). Even prior to the expiration of Toshiba's support ("repair under warranty until Dec 31, 2010"), there have been reports that this solution is prohibitively expensive, labor charges accruing even when the laptop is still under warranty, and other reports that are generally discouraging: "They were unable to fix it and the guy who worked on it said he couldn’t find the jumpers on the motherboard to clear the BIOS. I paid $39 for my troubles and still have the password problem." - Steve. Since the costs of the repairs can now exceed the value of the hardware, it would seem this is a DIY solution, or a non-solution (i.e. the hardware is trash). Build a Toshiba parallel loopback by stripping and soldering the wires on a DB25 plug to connect connect these pins: 1-5-10, 2-11, 3-17, 4-12, 6-16, 7-13, 8-14, 9-15, 18-25. -CGSecurity. According to a list of supported models on pwcrack, this will likely not work for my Satellite A55-1065 (as well as many other models of similar age). -pwcrack Disconnect the laptop battery for an extended period of time. Doesn't work, laptop sat in a closet for several years without the battery connected and I forgot about the whole thing for awhile. The poor thing. Clear CMOS by setting the proper jumper setting or by removing the CMOS (RTC) battery, or by short circuiting a (hidden?) jumper that looks like a pair of solder marks -various sources for various Satellite models: Satellite A105: "you will see C88 clearly labeled right next the jack that the wireless card plugs into. There are two little solder squares (approx 1/16") at this location" -kerneltrap Satellite 1800: "Underneath the RAM there is black sticker, peel off the black sticker and you will reveal two little solder marks which are actually 'jumpers'. Very carefully hold a flat-head screwdriver touching both points and power on the unit briefly, effectively 'shorting' this circuit." -shadowfax2020 Satellite L300: "Short the B500 solder pads on the system board." -Lester Escobar Satellite A215: "Short the B500 solder pads on the system board." -fixya Clearing the CMOS could resolve the issue, but I cannot locate a jumper or a battery on this board. Nothing that looks remotely like a battery can be removed (everything is soldered). I have looked closely at the area around the memory and do not see any obvious solder pads that could be a secret jumper. Here are pictures (click for full resolution) : Where is the jumper (or solder pads) to short circuit and wipe the CMOS on this board? Possibly related questions: Remove Toshiba laptop BIOS password? Password Problem Toshiba Satellite..

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  • Determining cause of high NFS/IO utilization without iotop

    - by Matt
    I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. Performance is miserable, with users often seeing multi-second lags for simple commands (like ls, or writing a small text file). Sometimes the home directory mount completely hangs for minutes, with users getting "permission denied" errors. The hardware is a Dell R510 with dual E5620 CPUs and 8 GB RAM. There are eight 15k 2.5” 600 GB drives (Seagate ST3600057SS) configured in hardware RAID-6 with a single hot spare. RAID controller is a Dell PERC H700 w/512MB cache (Linux sees this as a LSI MegaSAS 9260). OS is CentOS 5.6, home directory partition is ext3, with options “rw,data=journal,usrquota”. I have the HW RAID configured to present two virtual disks to the OS: /dev/sda for the OS (boot, root and swap partitions), and /dev/sdb for the home directories. What I find curious, and suspicious, is that the sda device often has very high utilization, even though it only contains the OS. I would expect this virtual drive to be idle almost all the time. The system is not swapping, according to "free" and "vmstat". Why would there be major load on this device? Here is a 30-second snapshot from iostat: Time: 09:37:28 AM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sdb 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 sdb1 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 dm-0 0.00 0.00 0.03 151.82 0.13 607.26 8.00 1.25 8.23 5.16 78.35 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 dm-3 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 Looks like iotop is the ideal tool to use to sniff out these kinds of issues. But I'm on CentOS 5.6, which doesn't have a new enough kernel to support that program. I looked at Determining which process is causing heavy disk I/O?, and besides iotop, one of the suggestions said to do a "echo 1 /proc/sys/vm/block_dump". I did that (after directing kernel messages to tempfs). In about 13 minutes I had about 700k reads or writes, roughly half from kjournald and the other half from nfsd: # egrep " kernel: .*(READ|WRITE)" messages | wc -l 768439 # egrep " kernel: kjournald.*(READ|WRITE)" messages | wc -l 403615 # egrep " kernel: nfsd.*(READ|WRITE)" messages | wc -l 314028 For what it's worth, for the last hour, utilization has constantly been over 90% for the home directory drive. My 30-second iostat keeps showing output like this: Time: 09:36:30 PM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sdb 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 sdb1 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 dm-0 0.00 0.00 0.20 17.76 0.80 71.04 8.00 0.38 21.21 9.22 16.57 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.81 dm-3 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.82

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  • Integrating HP Systems Insight Manager into an existing environment

    - by ewwhite
    I'm working with an environment that spans multiple data centers/sites and consists primarily of HP ProLiant servers (G5-G7) running Linux. The mix is 30% RHEL/CentOS, the rest are Gentoo :(. I also have a few dozen virtual machines running back-office and Windows servers on VMWare ESX hosts. I run OpenNMS to pull SNMP data from the various server nodes and networking devices. While OpenNMS works wonderfully for up/down, thresholds and notifications, it's native handling of traps is a little rough and the graphs are not particularly pretty. I use Orca/RRD graphs for performance trending and nice graphs. I'm tasked with inventorying the environment and wanted to come up with a clean way to organize server information. Since my environment is mostly HP, I've been playing with HP Systems Insight Manager as a way to extract server data and to deploy HP health/monitoring packages and firmware. The Gentoo systems eventually have to be converted to CentOS, so getting a quick assessment of what hardware is where would be great. Although I've read through a few hundred pages of HP manuals, I'm having a difficult time understanding how to get HP SIM to do what I want, though. My main problems are: I have about 40 subnets to deal with; 98% connected with private lines to facilities across the globe. I don't want to initiate an HP SIM discovery only to pull back every piece of intermediate networking hardware and equipment from all of the locations. I'd like this to focus on the servers. I have OpenNMS configured to accept traps. I don't want HP SIM to duplicate that effort. It seems like the built-in software deployment tool wants to overwrite the trapsink parameters for the systems it encounters during discovery. I have about 10 administrative username/password combinations in use across this infrastructure. Is there a more efficient way to get HP SIM to do the discovery or break discovery into manageable chunks? In terms of general workflow, do people typically install the HP Management Agents during the initial OS deployment (e.g. kickstart post script) or afterwards from HP SIM? Is HP SIM too thick/fat to be an inventory tool? I can't tell if it's meant to be used standalone or alongside other monitoring products. Since the majority of the systems I'm trying to track are those running Gentoo (in order to plan the move to CentOS), is there any way for HP SIM to extract system model information from them ( like dmidecode)? I have systems here where I may have an SSH key established, but not direct user or login access. Is there a way for me to import an SSH private/public key pair into HP SIM to reach out to the servers that can't accept standard credentials? There are a handful of sites where I have inconsistent access or have a double-NAT situation. I may be able to poke a server, but it may not be able to find its way back to the management system. Is there a workaround for this? The certificate configuration for HP SIM seems complicated. What is the preferred setup for trust between systems? I'd also appreciate any notes or recommendations to using this product. Or if there's a better way to do this, I'd like to know.

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  • Unmountable boot volume blue screen, what should I do?

    - by Josh
    I was trying to install an update from NVIDIA for my GTX 560, but while it was installing, my computer shut off. After a few minutes, I turned it back on. It got to the Windows boot screen and then had a blue screen error and if left on it would just keep doing that. A few details about my PC: I haven't added any new hardware or software, I'm running Windows XP Professional 32 bit and Windows XP Professional 64 bit on the same hard drive for about 2 years now. I have 2 other hard drives also, but I don't have one large enough to hold everything from my main hard drive, so formatting isn't an option. Now, as for what I've done so far: I've scanned the RAM with "memtest - 86 v3.4" and it said that it was good. I scanned the hard drive in question with chkdsk /r and it gets to 50% and tells me something along the lines of "the drive has one or more unrepairable problems". I also tried to use chkdsk on the drive I installed the new copy of Windows XP on and it got to 75% then jumped back down to 50% and stayed there (I had to reboot the pc). So, after that, I turned off auto reboot and got to read the blue screen error code and I looked it up only to find that nobody seems to have this problem, just problems close to it. The error code is 0x000000ed and I've seen a lot of these online but none that matched the detailed part of the code UNMOUNTABLE_BOOT_VOLUME 0x000000ed (0xfffffadf513c19a0, 0xffffffffc0000006, 0, 0) So, I have installed another copy of Windows XP Professional 32 bit on one of my other hard drives in hopes of accessing the data on the drive in question and when it booted it asked if I wanted chkdsk to scan the drive in question and this is what it found: file record segments 12740, 12741, 12742 and 12743 were reported unreadable. Then it says "recovering lost files" but it sits there for a few seconds and then just boots to Windows. I can't access the drive in question from Windows as far as I can tell, it just says "drive not accessible" and when I go to properties it says that the drive has 100% free space. So, after that failed I didn't give up, I looked for another way to access the drive in question. I used a Ubuntu bootable disk and was able to access the drive in question without any problems. However, I can't access the registry editor because it's a .exe file and that won't load from Ubuntu. I made a copy of the "Windows" folder and put it on one of my other drives and that's where I'm stuck at now. I'm sure my drive works fine, I know chkdsk can't fix the problem with it and I know what caused the problem in the first place for the most part, but I don't know what to do about it. I have a laptop that I can use to download and burn disks if needed and I also have the other copy of Windows XP Professional 32 bit that I can use that's installed on the computer in question (so I know it's not a hardware issue). I'm pretty sure it's a driver issue or the update was editing the registry when it shut off and left me when a broken registry. I've tried accessing C:\Windows\System32\CONFIG only to find that the Windows XP disk repair option can't even access the files on the drive in question. It seems I'll need to be able to do everything from Ubuntu unless there is something I haven't tried with the Windows XP disk. I didn't install the update on Windows XP 64 bit but yet it also has the same blue screen error (that's where the error code above came from but I haven't checked to see if they are the same). They both stopped working at the same time, so I assume it's one problem causing both to not work.

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  • reiserfsck on lvm

    - by DaDaDom
    It seems like my filesystem got corrupted somehow during the last reboot of my server. I can't fsck some logical volumes anymore. The setup: root@rescue ~ # cat /mnt/rescue/etc/fstab proc /proc proc defaults 0 0 /dev/md0 /boot ext3 defaults 0 2 /dev/md1 / ext3 defaults,errors=remount-ro 0 1 /dev/systemlvm/home /home reiserfs defaults 0 0 /dev/systemlvm/usr /usr reiserfs defaults 0 0 /dev/systemlvm/var /var reiserfs defaults 0 0 /dev/systemlvm/tmp /tmp reiserfs noexec,nosuid 0 2 /dev/sda5 none swap defaults,pri=1 0 0 /dev/sdb5 none swap defaults,pri=1 0 0 [UPDATE] First question: what "part" should I check for bad blocks? The logical volume, the underlying /dev/md or the /dev/sdx below that? Is doing what I am doing the right way to go? [/UPDATE] The errormessage when checking /dev/systemlvm/usr: root@rescue ~ # reiserfsck /dev/systemlvm/usr reiserfsck 3.6.19 (2003 www.namesys.com) [...] Will read-only check consistency of the filesystem on /dev/systemlvm/usr Will put log info to 'stdout' Do you want to run this program?[N/Yes] (note need to type Yes if you do):Yes ########### reiserfsck --check started at Wed Feb 3 07:10:55 2010 ########### Replaying journal.. Reiserfs journal '/dev/systemlvm/usr' in blocks [18..8211]: 0 transactions replayed Checking internal tree.. Bad root block 0. (--rebuild-tree did not complete) Aborted Well so far, let's try --rebuild-tree: root@rescue ~ # reiserfsck --rebuild-tree /dev/systemlvm/usr reiserfsck 3.6.19 (2003 www.namesys.com) [...] Will rebuild the filesystem (/dev/systemlvm/usr) tree Will put log info to 'stdout' Do you want to run this program?[N/Yes] (note need to type Yes if you do):Yes Replaying journal.. Reiserfs journal '/dev/systemlvm/usr' in blocks [18..8211]: 0 transactions replayed ########### reiserfsck --rebuild-tree started at Wed Feb 3 07:12:27 2010 ########### Pass 0: ####### Pass 0 ####### Loading on-disk bitmap .. ok, 269716 blocks marked used Skipping 8250 blocks (super block, journal, bitmaps) 261466 blocks will be read 0%....20%....40%....60%....80%....100% left 0, 11368 /sec 52919 directory entries were hashed with "r5" hash. "r5" hash is selected Flushing..finished Read blocks (but not data blocks) 261466 Leaves among those 13086 Objectids found 53697 Pass 1 (will try to insert 13086 leaves): ####### Pass 1 ####### Looking for allocable blocks .. finished 0% left 12675, 0 /sec The problem has occurred looks like a hardware problem (perhaps memory). Send us the bug report only if the second run dies at the same place with the same block number. mark_block_used: (39508) used already Aborted Bad. But let's do it again as mentioned: [...] Flushing..finished Read blocks (but not data blocks) 261466 Leaves among those 13085 Objectids found 54305 Pass 1 (will try to insert 13085 leaves): ####### Pass 1 ####### Looking for allocable blocks .. finished 0%... left 12127, 958 /sec The problem has occurred looks like a hardware problem (perhaps memory). Send us the bug report only if the second run dies at the same place with the same block number. build_the_tree: Nothing but leaves are expected. Block 196736 - internal Aborted Same happens every time, only the actual error message changes. Sometimes I get mark_block_used: (somenumber) used already, other times the block number changes. Seems like something is REALLY broken. Are there any chances I can somehow get the partitions to work again? It's a server to which I don't have physical access directly (hosted server). Thanks in advance!

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  • Troubleshooting unwanted NTP Traffic

    - by Jaxaeon
    A domain controller running Windows Server 2012 is sending NTP and NETBIOS traffic to an address that has never been configured as a time provider. The server logs give no indication that any NTP traffic is failing. The only place I see any evidence of this traffic is in pfSense system logs: (Blocked) Jun 9 08:48:50 DOMAIN 10.0.1.100:123 192.128.127.254:123 UDP (Blocked) Jun 9 08:48:53 DOMAIN 10.0.1.100:137 192.128.127.254:137 UDP As far as I can tell the NTP service is working normally otherwise: DC2.domain.com[10.0.1.101:123]: ICMP: 0ms delay NTP: -0.0131705s offset from DC1.domain.com RefID: DC1.domain.com [10.0.1.100] Stratum: 3 DC1.domain.com *** PDC ***[10.0.1.100:123]: ICMP: 0ms delay NTP: +0.0000000s offset from DC1.domain.com RefID: clock1.albyny.inoc.net [64.246.132.14] Stratum: 2 The time provider NtpClient is currently receiving valid time data from 1.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->204.2.134.163:123). The time provider NtpClient is currently receiving valid time data from 0.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->64.246.132.14:123). The time service is now synchronizing the system time with the time source 0.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->64.246.132.14:123). I've been inside and out of the NTP configuration and cannot find any reason for this traffic. Reverse DNS points the destination address to nothing.attdns.com. pinging nothing.attdns.com from the domain controller in question leads to a response from loopback (127.0.0.2) which makes my head hurt. Any ideas? EDIT1: It should probably be noted that after a dns flush, nslookup 192.128.127.254 returns nothing.attdns.com. 192.128.127.254 is not present in domain.com DNS records. The attdns.com domain is not present in cached lookups. 127.in-addr.arpa is clean of any funkyness. EDIT2: The loopback ping response from nothing.attdns.com is possibly unrelated. Machines on other networks are also displaying this behavior. EDIT3: As mentioned in the comments, I tracked the problem network adapter back to my pfSense VM hosted in esxi 5.5 (I know shame on me for virtualizing a firewall). pfSense was configured to use DC1.domain.com as its primary time provider, but upon changing it back to pool.ntp.org the problem persists. pfSense logs give no indication of NTP misconfiguration. Everywhere I can think to look this VM is identified as 10.0.1.253, so I still have no idea why it’s sending NTP requests as 192.128… Since this firewall was a temporary solution to a problem that no longer exists so I am going to decommission it. EDIT4: The queries were coming from another machine sharing the same virtual adapter as the firewall. The machine has two local adapters: one for LAN, and the other for attached hardware that uses an Ethernet connection. That hardware sits in the the mystery subnet, and the machine is broadcasting NTP requests over both adapters.

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  • Did a recent WinXP update break CD/DVD read speeds? SP2/SP3

    - by quack quixote
    I have two systems with fresh installations of Windows XP Pro SP3 (SP3 slipstreamed into the installer; fully updated after install). One's a refurbished 2.4GHz Pentium4 system; the other is a new 1.6GHz Atom330 build. Both have brand-new dual-layer CD/DVD burners (one's a LiteOn IDE, the other an LG SATA). Both take a really looooong time to read a single-layer DVD in Windows with Cygwin tools. Specifically, 40 minutes or more. I burn backup data to single-layer DVD+/-R and use MD5 hashes for data verification (made with the standard md5sum tool in Unix or Cygwin). The hashes are burned to disc with the data files, and I use this command to verify: $ cd /path/to/disc/mountpoint ; time md5sum -c < md5.txt Here's how long that takes to run on a full single-layer DVD+/-R disc: Old system (WinXP SP2, 1.8GHz Athlon 2500+, last summer): ~10 minutes Old system (Ubuntu 9.04, 1.8GHz Athlon 2500+): ~10 minutes Old system (Debian 5, dual 550MHz P3): ~10 minutes New Pentium4 system (running Ubuntu 9.04): ~5 minutes New Pentium4 system (running WinXP SP3, file copy from Win Explorer): ~6 minutes New Atom330 system (running WinXP SP3, file copy from Win Explorer): ~6 minutes Now the weird stuff: Old system (WinXP SP2, 1.8GHz Athlon 2500+, today): ~25 minutes New Pentium4 system (running WinXP SP3, read from Cygwin): ~40-50 minutes (?!!) New Atom330 system (running WinXP SP3, read from Cygwin): ~40 minutes (can do it in ~30 minutes ...if i have another program spin up the drive first) Since both systems will copy files in 6 minutes using Windows Explorer, I know it's not a hardware problem. Windows just never spins up the drive during the Cygwin read, so it stays super-slow the whole time. Other programs like EAC and DVD Decrypter seem to spin up the disc just fine during their processing. DMA is enabled on both systems. (Can confirm in Windows' Device Manager on the Atom330, not on the P4.) Nero's DriveSpeed tool doesn't seem to have any effect. Copy times are comparable from commandline with Windows' xcopy. Copying with Cygwin's cp looks more like the problem state -- it will spin up the drive for a short time, never reaches full speed, and lets it spin back down again for most of the copy. What I need is to get full read speeds from Cygwin. Is this a known issue with SP3 or some other recent Windows update? Any other ideas? Update: More testing; Windows will spin up the drive when data is copied with Windows tools, but not when read in place or copied with Cygwin tools. It doesn't make sense to me that Windows spins up the drive for copying, but not for other reads. Might be more of a Cygwin problem? Update 2: GUI activity is sluggish during the problem state -- during the Cygwin verifies, there's a slight but noticable delay when dragging windows or icons around on the desktop, switching windows, Alt-Tabbing through open applications, opening new windows, etc. It reminds me of the delay when opening a Windows Explorer window on My Computer just after inserting a DVD. I've tried updating Cygwin (from 1.5.x to 1.7.x), but no change in the problem behavior. I've also noticed this issue occurs on WinXP SP2, but it's not exactly the same -- some spin-up occurs, so the read happens in ~25-30 minutes instead of 40+. The SP2 system used to run the verifies in ~10 minutes, and when it first changed (not sure exactly when, maybe in late November or early December 2009) I thought it was dying hardware. This is why I suspect an official update of breaking this functionality; this has worked for years on that SP2 box.

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  • BluRay audio/video stuttering with PowerDVD 11, WinDVD 11 Pro, etc? Xonar/Auzen HD audio option?

    - by jrista
    I recently upgraded my Windows 7 MediaCenter HTPC due to a motherboard failure (really old motherboard and cpu, it was on its last legs.) I chose to upgrade to an i5 system with everything built into the motherboard. I did my due diligence, researched, and found some hardware that was within my budget. I ended up with: Core i5 2500K (3.3Ghz) Corsair XMS3 2x2Gb DDR3 (4Gb) ASUS P8H 61-M LE/CSM MicroCenter 64Gb SSD (Previous BluRay player, forget the brand) The system is pretty awesome, and plays everything I have perfectly. I almost went with an Atom solution, however there have been numerous notes that they do not play NetFlix Instant Watch well...and I am a heavy Netflix IW user. High definition BluRay rips work well, although they usually contain lower audio quality than the BluRay's they were ripped from. The real problem I am encountering is playing back BluRay video from discs. For some reason, I am encountering rather terrible stuttering problems with both the audio and video. The stuttering is synchronous in both, and occurs at seemingly random intervals. I've used PowerDVD 9, PowerDVD 11 trial, and WinDVD 11 Pro trial. All three have stuttering problems, although PowerDVD 11 seems to have the least. Watching system resource usage, CPU load is never above 20%, and memory usage tends to be a constant 1/3rd the total available system memory. When playback is fine, its superb...the video is crystal clear. The audio quality is ok, certainly not what I would expect from a BluRay disc. I did some research, and it seems that playing BluRay from a PC causes a downsampling of the audio? I am curious if the audio is my primary problem here, the cause of the stuttering I am encountering? When stuttering occurs, the audio gets REALLY bad, while the video just pauses momentarily every second until for whatever reason everything picks up and runs fine (usually after a few seconds to a couple minutes.) The audio chipset is a Realtek HD ALC887 8-channel, supposedly designed to support BluRay playback. Has anyone encountered any issues like this playing back bluray discs on a PC (namely with PowerDVD...WinDVD was FAR worse, and seemed to have real trouble even reading the discs, and I have no interest in fiddling with it further.) Is there any reason to suspect the video decoding as the problem?(Given how bad the audio gets during a stutter, and how clean the video remains, I am inclined to think the issue boils down to audio.) Is it even remotely possible that the motherboard, cpu, or ram are causing the stuttering (all three are pretty blazing fast...faster than the hardware that I replaced, which seemed to play BluRay fine with PowerDVD 9.) I've read a bit about the Asus Xonar HDAV 1.3 and the Auzen X-Fi HomeTheater HD home theater hi-fi audio cards. Seems they are the only way to get true full-quality, uncompressed BluRay audio bitstreaming over HDMI on a PC. None of the usual suspects seem to have these cards in stock, however. Are these cards worth getting? Are they even still available, or have they been discontinued (if so, that would indeed be sad...they sound simply fantastic.)

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  • Cheapest way to connect 20-24 Sata II HDDs in a budget storage server?

    - by Joe Hopfgartner
    I need to assemble a high density storage server for as cheap as possible. It's been a while for me and the last systems I integrated didn't even have Sata yet... During my Research I of course stumbled about Nexsan SATA Beast, the BackBlaze storage Pods as well as some ridiculously overpriced HP Proliant or Dell storage solutions. Finally I choose Norco cases as the way to go. My eye is set on the RPC-4020, which is a 4U 19" Rackmount case with 20 Hot Swap 3.5" SATA/SAS Hdd trays (Backplanes included) and room for two 2.5" OS drives as well as a Slim Line CD-Rom. The backplanes connect with a single SATA port for each drive, so there are 20 internal SATA ports to to be connected. They also have redundant power ports which I think is quite nice. The cheapest price I have found is 290$ + 40$ shipping. In europe the cheapest unfortunately is 370€ (500$) + 40 € shipping... A nice alternative would be the RPC-4224 which has SFF-8087 Mini SAS connectors that bundle 4 SATA trays each. But it doesn't seem to be available in Europe (where i am) anywhere. So here comes my problem: What Mainboard/Controller to choose to connect them for as cheap as possible while still having nice data rates? I have to say that the server is intended as a Storage server with 1gps connectivity and the data transfer will be distributed very evenly across all drives. I also don't require any raid functionality. This is all done at application level, I just need JBOD. So for example if I go for the RPC 4020 Model I need to connect 20 Storage + 1 OS + 1 CDROM Sata ports. I searched a bit and stumbled across this very low priced controller: http://www.intel.com/products/server/raid-controllers/SASWT4I/SASWT4I-overview.htm They sell it for 115 € here and the specs say it can control up to 122 hard discs and has 4 Mini SAS connectors. So I would use 4 Mini SAS 36pin - 4 SATA 7pin cables to connect 4 SATA drives to each port and choose a Mainboard taht has 6 SATA on board (for example this one) and hurray, I can connect my 22 SATA devices for as low as about ~ 220 EUR (cpu, ram, psu, case not counted) Question: WOULD THAT WORK? And if not, why? 2nd Question: If I go for the 4220 or 4224 Model, I have internal Mini SAS connectors. Am I right in assuming that the backplane than acts as a "SAS Expander"? And can I just plug these SAS connectors into any SAS port I can find on my controller / mainboard or are there certain requirements? I know that SATA port multipliers only work with controllers that are ready for that. But isn't this expansion already implemented in the SAS standard? I am sorry that this is a very broad question, but I really spent the last week reading up and it seems to be not so clear! Especially all the controlling hardware specifications! 3rd Question: A lot of hardware specs feature "internal channels" and "internal connectors". The connecors are the physical numbers of places where I can plug a cable in. I got that. But are the "internal channels" always the maximum numbers of physical drives that can be used in the end? Or can I enhance this further by Expanders/Fanouts? 4th and last question: What do you think about the setup so far? Do you know any good alternatives? Maby I am completely going the wrong way and some DAS would be way better? Are there any comparable chassis available in europe? Please feel free to say whatever you think is relevant to the subject!

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  • Why my laptop sends ARP request to itself ?

    - by user58859
    I have just started to learn about protocols. While studying the packets in wireshark, I came across a ARP request sent by my machine to my own IP. Here is the details of the packet : No. Time Source Destination Protocol Info 15 1.463563 IntelCor_aa:aa:aa Broadcast ARP Who has 192.168.1.34? Tell 0.0.0.0 Frame 15: 42 bytes on wire (336 bits), 42 bytes captured (336 bits) Arrival Time: Jan 7, 2011 18:51:43.886089000 India Standard Time Epoch Time: 1294406503.886089000 seconds [Time delta from previous captured frame: 0.123389000 seconds] [Time delta from previous displayed frame: 0.123389000 seconds] [Time since reference or first frame: 1.463563000 seconds] Frame Number: 15 Frame Length: 42 bytes (336 bits) Capture Length: 42 bytes (336 bits) [Frame is marked: False] [Frame is ignored: False] [Protocols in frame: eth:arp] [Coloring Rule Name: ARP] [Coloring Rule String: arp] Ethernet II, Src: IntelCor_aa:aa:aa (aa:aa:aa:aa:aa:aa), Dst: Broadcast (ff:ff:ff:ff:ff:ff) Destination: Broadcast (ff:ff:ff:ff:ff:ff) Address: Broadcast (ff:ff:ff:ff:ff:ff) .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast) .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default) Source: IntelCor_aa:aa:aa (aa:aa:aa:aa:aa:aa) Address: IntelCor_aa:aa:aa (aa:aa:aa:aa:aa:aa) .... ...0 .... .... .... .... = IG bit: Individual address (unicast) .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default) Type: ARP (0x0806) Address Resolution Protocol (request) Hardware type: Ethernet (0x0001) Protocol type: IP (0x0800) Hardware size: 6 Protocol size: 4 Opcode: request (0x0001) [Is gratuitous: False] Sender MAC address: IntelCor_aa:aa:aa (aa:aa:aa:aa:aa:aa) Sender IP address: 0.0.0.0 (0.0.0.0) Target MAC address: 00:00:00_00:00:00 (00:00:00:00:00:00) Target IP address: 192.168.1.34 (192.168.1.34) Here the sender's mac address is mine(Here I have hiden my mac address). target IP is mine. Why my machine is sending ARP request to itself? I found 3 packets of this type. There was no ARP reply for these packets. Can anybody explain me why it is? (My operating system is windows-7. I am directly connected to a wifi modem. I got these packets as soon as I started my connection.) I want one suggestion also. many places I read that RFC's are enough for study about protocols. I studied the RFC 826 on ARP. I personally feel that is not enough at all. Any suggestion regarding this? Is there more then 1 RFC for a protocol? I want to study about the protocols in very detail. Can anybody guide me for this? Thanks in advance.

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  • Proliant server will not accept new hard disks in RAID 1+0?

    - by Leigh
    I have a HP ProLiant DL380 G5, I have two logical drives configured with RAID. I have one logical drive RAID 1+0 with two 72 gb 10k sas 1 port spare no 376597-001. I had one hard disk fail and ordered a replacement. The configuration utility showed error and would not rebuild the RAID. I presumed a hard disk fault and ordered a replacement again. In the mean time I put the original failed disk back in the server and this started rebuilding. Currently shows ok status however in the log I can see hardware errors. The new disk has come and I again have the same problem of not accepting the hard disk. I have updated the P400 controller with the latest firmware 7.24 , but still no luck. The only difference I can see is the original drive has firmware 0103 (same as the RAID drive) and the new one has HPD2. Any advice would be appreciated. Thanks in advance Logs from server ctrl all show config Smart Array P400 in Slot 1 (sn: PAFGK0P9VWO0UQ) array A (SAS, Unused Space: 0 MB) logicaldrive 1 (68.5 GB, RAID 1, Interim Recovery Mode) physicaldrive 2I:1:1 (port 2I:box 1:bay 1, SAS, 73.5 GB, OK) physicaldrive 2I:1:2 (port 2I:box 1:bay 2, SAS, 72 GB, Failed array B (SAS, Unused Space: 0 MB) logicaldrive 2 (558.7 GB, RAID 5, OK) physicaldrive 1I:1:5 (port 1I:box 1:bay 5, SAS, 300 GB, OK) physicaldrive 2I:1:3 (port 2I:box 1:bay 3, SAS, 300 GB, OK) physicaldrive 2I:1:4 (port 2I:box 1:bay 4, SAS, 300 GB, OK) ctrl all show config detail Smart Array P400 in Slot 1 Bus Interface: PCI Slot: 1 Serial Number: PAFGK0P9VWO0UQ Cache Serial Number: PA82C0J9VWL8I7 RAID 6 (ADG) Status: Disabled Controller Status: OK Hardware Revision: E Firmware Version: 7.24 Rebuild Priority: Medium Expand Priority: Medium Surface Scan Delay: 15 secs Surface Scan Mode: Idle Wait for Cache Room: Disabled Surface Analysis Inconsistency Notification: Disabled Post Prompt Timeout: 0 secs Cache Board Present: True Cache Status: OK Cache Status Details: A cache error was detected. Run more information. Cache Ratio: 100% Read / 0% Write Drive Write Cache: Disabled Total Cache Size: 256 MB Total Cache Memory Available: 208 MB No-Battery Write Cache: Disabled Battery/Capacitor Count: 0 SATA NCQ Supported: True Array: A Interface Type: SAS Unused Space: 0 MB Status: Failed Physical Drive Array Type: Data One of the drives on this array have failed or has Logical Drive: 1 Size: 68.5 GB Fault Tolerance: RAID 1 Heads: 255 Sectors Per Track: 32 Cylinders: 17594 Strip Size: 128 KB Full Stripe Size: 128 KB Status: Interim Recovery Mode Caching: Enabled Unique Identifier: 600508B10010503956574F305551 Disk Name: \\.\PhysicalDrive0 Mount Points: C:\ 68.5 GB Logical Drive Label: A0100539PAFGK0P9VWO0UQ0E93 Mirror Group 0: physicaldrive 2I:1:2 (port 2I:box 1:bay 2, S Mirror Group 1: physicaldrive 2I:1:1 (port 2I:box 1:bay 1, S Drive Type: Data physicaldrive 2I:1:1 Port: 2I Box: 1 Bay: 1 Status: OK Drive Type: Data Drive Interface Type: SAS Size: 73.5 GB Rotational Speed: 10000 Firmware Revision: 0103 Serial Number: B379P8C006RK Model: HP DG072A9B7 PHY Count: 2 PHY Transfer Rate: Unknown, Unknown physicaldrive 2I:1:2 Port: 2I Box: 1 Bay: 2 Status: Failed Drive Type: Data Drive Interface Type: SAS Size: 72 GB Rotational Speed: 15000 Firmware Revision: HPD9 Serial Number: D5A1PCA04SL01244 Model: HP EH0072FARUA PHY Count: 2 PHY Transfer Rate: Unknown, Unknown Array: B Interface Type: SAS Unused Space: 0 MB Status: OK Array Type: Data Logical Drive: 2 Size: 558.7 GB Fault Tolerance: RAID 5 Heads: 255 Sectors Per Track: 32 Cylinders: 65535 Strip Size: 64 KB Full Stripe Size: 128 KB Status: OK Caching: Enabled Parity Initialization Status: Initialization Co Unique Identifier: 600508B10010503956574F305551 Disk Name: \\.\PhysicalDrive1 Mount Points: E:\ 558.7 GB Logical Drive Label: AF14FD12PAFGK0P9VWO0UQD007 Drive Type: Data physicaldrive 1I:1:5 Port: 1I Box: 1 Bay: 5 Status: OK Drive Type: Data Drive Interface Type: SAS Size: 300 GB Rotational Speed: 10000 Firmware Revision: HPD4 Serial Number: 3SE07QH300009923X1X3 Model: HP DG0300BALVP Current Temperature (C): 32 Maximum Temperature (C): 45 PHY Count: 2 PHY Transfer Rate: Unknown, Unknown physicaldrive 2I:1:3 Port: 2I Box: 1 Bay: 3 Status: OK Drive Type: Data Drive Interface Type: SAS Size: 300 GB Rotational Speed: 10000 Firmware Revision: HPD4 Serial Number: 3SE0AHVH00009924P8F3 Model: HP DG0300BALVP Current Temperature (C): 34 Maximum Temperature (C): 47 PHY Count: 2 PHY Transfer Rate: Unknown, Unknown physicaldrive 2I:1:4 Port: 2I Box: 1 Bay: 4 Status: OK Drive Type: Data Drive Interface Type: SAS Size: 300 GB Rotational Speed: 10000 Firmware Revision: HPD4 Serial Number: 3SE08NAK00009924KWD6 Model: HP DG0300BALVP Current Temperature (C): 35 Maximum Temperature (C): 47 PHY Count: 2 PHY Transfer Rate: Unknown, Unknown

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  • What would cause Memcached to Hang for 2+ seconds?

    - by Brad Dwyer
    I'm going nuts trying to scale memcached. From their site: Memcached operations are almost all O(1). Connecting to it and issuing a get or stat command should never lag. If connecting lags, you may be hitting the max connections limit. See ServerMaint for details on stats to monitor. If issuing commands lags, you can have a number of tuning problems. Most common are hardware problems, not enough RAM (swapping), network problems (bandwidth, dropped packets, half-duplex connections). On rare occasion OS bugs or memcached bugs can contribute. Well.. it is most certainly not performing like an O(1) operation for me. Under low to normal load on our site memcached response times for get and set ops are about 0.001 seconds. Not bad. But if we triple the load we get outliers that take 100x (or in rare cases 1000x!) that long. I even had one instance where it took 2.2442 seconds for memcached to store a value. Obviously this is killing our site. Here's the output of Memcached-getStats during one of the slow periods: [pid] => 18079 [uptime] => 8903 [threads] => 4 [time] => 1332795759 [pointer_size] => 32 [rusage_user_seconds] => 26 [rusage_user_microseconds] => 503872 [rusage_system_seconds] => 125 [rusage_system_microseconds] => 477008 [curr_items] => 42099 [total_items] => 422500 [limit_maxbytes] => 943718400 [curr_connections] => 84 [total_connections] => 4946 [connection_structures] => 178 [bytes] => 7259957 [cmd_get] => 1679091 [cmd_set] => 351809 [get_hits] => 1662048 [get_misses] => 17043 [evictions] => 0 [bytes_read] => 109388476 [bytes_written] => 3187646458 [version] => 1.4.13 So things that I have ruled out so far are: Hitting the max connections limit (curr_connections of 84 is well below the default of max of 1024) Swapping - the machine has 900M out of 1024M of memory dedicated to memcached on a dedicated machine. It only appears to be using about 7MB of data as per the bytes stat. How would I diagnose the other hardware problems? prstat doesn't really show a whole lot going on in terms of CPU or memory usage. Not sure how to figure out the network problems but as this is a dedicated server on the same private network as the web box I don't think it's a connectivity issue (ping is less than a millisecond between the boxes). Is there something else I'm missing here? It's driving me nuts. Edit: Also forgot to mention that I've tried both persistent and non-persistent connections with minimal-to-no impact.

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  • File Server - Storage configuration: RAID vs LVM vs ZFS something else... ?

    - by privatehuff
    We are a small company that does video editing, among other things, and need a place to keep backup copies of large media files and make it easy to share them. I've got a box set up with Ubuntu Server and 4 x 500 GB drives. They're currently set up with Samba as four shared folders that Mac/Windows workstations can see fine, but I want a better solution. There are two major reasons for this: 500 GB is not really big enough (some projects are larger) It is cumbersome to manage the current setup, because individual hard drives have different amounts of free space and duplicated data (for backup). It is confusing now and that will only get worse once there are multiple servers. ("the project is on sever2 in share4" etc) So, I need a way to combine hard drives in such a way as to avoid complete data loss with the failure of a single drive, and so users see only a single share on each server. I've done linux software RAID5 and had a bad experience with it, but would try it again. LVM looks ok but it seems like no one uses it. ZFS seems interesting but it is relatively "new". What is the most efficient and least risky way to to combine the hdd's that is convenient for my users? Edit: The Goal here is basically to create servers that contain an arbitrary number of hard drives but limit complexity from an end-user perspective. (i.e. they see one "folder" per server) Backing up data is not an issue here, but how each solution responds to hardware failure is a serious concern. That is why I lump RAID, LVM, ZFS, and who-knows-what together. My prior experience with RAID5 was also on an Ubuntu Server box and there was a tricky and unlikely set of circumstances that led to complete data loss. I could avoid that again but was left with a feeling that I was adding an unnecessary additional point of failure to the system. I haven't used RAID10 but we are on commodity hardware and the most data drives per box is pretty much fixed at 6. We've got a lot of 500 GB drives and 1.5 TB is pretty small. (Still an option for at least one server, however) I have no experience with LVM and have read conflicting reports on how it handles drive failure. If a (non-striped) LVM setup could handle a single drive failing and only loose whichever files had a portion stored on that drive (and stored most files on a single drive only) we could even live with that. But as long as I have to learn something totally new, I may as well go all the way to ZFS. Unlike LVM, though, I would also have to change my operating system (?) so that increases the distance between where I am and where I want to be. I used a version of solaris at uni and wouldn't mind it terribly, though. On the other end on the IT spectrum, I think I may also explore FreeNAS and/or Openfiler, but that doesn't really solve the how-to-combine-drives issue.

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  • Vista 64-bit, DISK BOOT FAILURE

    - by weka
    So I have this Acer Aspire AX3200-U3600A with Windows Vista (64-bit). Every night I turn it off and turn it back on in the morning. Around three weeks ago, I did a fresh factory reimage. Good as new. Then around two days ago, when I turned it on, I noticed it was running extremly slow. As in, it would often freeze up while I had multiple applications open when it usually never froze up. So I decided to restart my computer. Big mistake. My computer froze right after I clicked shut-down. I waited a while. Nothing. Waited some minutes. Nope. I decided to shut it down by pressing the power button. Here is where the problems begin. When I turned it back on, I saw the Windows logo and loading bar and then it loaded to black. I turned it off again forcefully by power button and then once more... then I got: AMD Data Change... Update New Data to DMI! then later the screen clears and I get: AHCI Option ROM BIOS Revision: 01.05.92 Date: 02-19-2008 Copyright (c) 2006-2008 Phoenix Technologies, LTD Port 01: Reset Port Error!! Port 02: then the screen clears again but this time, this loads from the bottom: Nvidia Boot Agent 249.0542 (copyright stuff... blah blah) PXE-E61: Media test failure, check cable. PXE-M0F: Exiting Nvidia Boot Agent DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER. So I try to go into Safe Mode. Well, first of all it doesn't load as fast. After it loads disk.sys from windows/drivers, it will wait a while (2-3 mins) THEN load. However it loads the Acer eRecovery Management Tool. I have three options: Reset computer to factory default, Restore computer from user's backup, or Exit. However, the top two options are gray and disabled where as the Exit is in blue and definitely clickable. So obviously safe mode is not there... A strong thing to note: In the beginning when all of this started, I did a Boot Windows Normal from pressing f8 and I got to my desktop! It logged me in. I could see the icons on my files. However my desktop was extremely slow as in when I clicked on the Start menu, it would wait a while, then load up the menu with JUST the gradient, no text or icons... so as you can see... it saw my HDD? Also, before anyone says, I have NO USB plugged in. My mouse and keyboard are not USB inputs, I assure you. And this came without a recovery CD AND when I went in BIOS, to change the BOOT ORDER, I did NOT see a CD-ROM option. And when I tried pressing ALT+F10 to get into Acer eRecovery Management, the top two options were disabled as well. But sometimes on start-up, I get: Windows has encountered a problem communicating with a device connected to your computer. This error can be caused by unplugging a removable storage device such as an external USB drive while the device is in use, or by faulty hardware such as a hard drive or CD-ROM drive that is failing. Make sure any removeable storage is properly connected and then restart your computer. If you continue to receive this error message, contact the hardware manufacturer. Status: 0xc00000e9 Info: An unexpected I/O error has occured. Then I tried Last Known Good Configuration Settings, that gives me a BSOD. What should I do/

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  • Parallelism in .NET – Part 5, Partitioning of Work

    - by Reed
    When parallelizing any routine, we start by decomposing the problem.  Once the problem is understood, we need to break our work into separate tasks, so each task can be run on a different processing element.  This process is called partitioning. Partitioning our tasks is a challenging feat.  There are opposing forces at work here: too many partitions adds overhead, too few partitions leaves processors idle.  Trying to work the perfect balance between the two extremes is the goal for which we should aim.  Luckily, the Task Parallel Library automatically handles much of this process.  However, there are situations where the default partitioning may not be appropriate, and knowledge of our routines may allow us to guide the framework to making better decisions. First off, I’d like to say that this is a more advanced topic.  It is perfectly acceptable to use the parallel constructs in the framework without considering the partitioning taking place.  The default behavior in the Task Parallel Library is very well-behaved, even for unusual work loads, and should rarely be adjusted.  I have found few situations where the default partitioning behavior in the TPL is not as good or better than my own hand-written partitioning routines, and recommend using the defaults unless there is a strong, measured, and profiled reason to avoid using them.  However, understanding partitioning, and how the TPL partitions your data, helps in understanding the proper usage of the TPL. I indirectly mentioned partitioning while discussing aggregation.  Typically, our systems will have a limited number of Processing Elements (PE), which is the terminology used for hardware capable of processing a stream of instructions.  For example, in a standard Intel i7 system, there are four processor cores, each of which has two potential hardware threads due to Hyperthreading.  This gives us a total of 8 PEs – theoretically, we can have up to eight operations occurring concurrently within our system. In order to fully exploit this power, we need to partition our work into Tasks.  A task is a simple set of instructions that can be run on a PE.  Ideally, we want to have at least one task per PE in the system, since fewer tasks means that some of our processing power will be sitting idle.  A naive implementation would be to just take our data, and partition it with one element in our collection being treated as one task.  When we loop through our collection in parallel, using this approach, we’d just process one item at a time, then reuse that thread to process the next, etc.  There’s a flaw in this approach, however.  It will tend to be slower than necessary, often slower than processing the data serially. The problem is that there is overhead associated with each task.  When we take a simple foreach loop body and implement it using the TPL, we add overhead.  First, we change the body from a simple statement to a delegate, which must be invoked.  In order to invoke the delegate on a separate thread, the delegate gets added to the ThreadPool’s current work queue, and the ThreadPool must pull this off the queue, assign it to a free thread, then execute it.  If our collection had one million elements, the overhead of trying to spawn one million tasks would destroy our performance. The answer, here, is to partition our collection into groups, and have each group of elements treated as a single task.  By adding a partitioning step, we can break our total work into small enough tasks to keep our processors busy, but large enough tasks to avoid overburdening the ThreadPool.  There are two clear, opposing goals here: Always try to keep each processor working, but also try to keep the individual partitions as large as possible. When using Parallel.For, the partitioning is always handled automatically.  At first, partitioning here seems simple.  A naive implementation would merely split the total element count up by the number of PEs in the system, and assign a chunk of data to each processor.  Many hand-written partitioning schemes work in this exactly manner.  This perfectly balanced, static partitioning scheme works very well if the amount of work is constant for each element.  However, this is rarely the case.  Often, the length of time required to process an element grows as we progress through the collection, especially if we’re doing numerical computations.  In this case, the first PEs will finish early, and sit idle waiting on the last chunks to finish.  Sometimes, work can decrease as we progress, since previous computations may be used to speed up later computations.  In this situation, the first chunks will be working far longer than the last chunks.  In order to balance the workload, many implementations create many small chunks, and reuse threads.  This adds overhead, but does provide better load balancing, which in turn improves performance. The Task Parallel Library handles this more elaborately.  Chunks are determined at runtime, and start small.  They grow slowly over time, getting larger and larger.  This tends to lead to a near optimum load balancing, even in odd cases such as increasing or decreasing workloads.  Parallel.ForEach is a bit more complicated, however. When working with a generic IEnumerable<T>, the number of items required for processing is not known in advance, and must be discovered at runtime.  In addition, since we don’t have direct access to each element, the scheduler must enumerate the collection to process it.  Since IEnumerable<T> is not thread safe, it must lock on elements as it enumerates, create temporary collections for each chunk to process, and schedule this out.  By default, it uses a partitioning method similar to the one described above.  We can see this directly by looking at the Visual Partitioning sample shipped by the Task Parallel Library team, and available as part of the Samples for Parallel Programming.  When we run the sample, with four cores and the default, Load Balancing partitioning scheme, we see this: The colored bands represent each processing core.  You can see that, when we started (at the top), we begin with very small bands of color.  As the routine progresses through the Parallel.ForEach, the chunks get larger and larger (seen by larger and larger stripes). Most of the time, this is fantastic behavior, and most likely will out perform any custom written partitioning.  However, if your routine is not scaling well, it may be due to a failure in the default partitioning to handle your specific case.  With prior knowledge about your work, it may be possible to partition data more meaningfully than the default Partitioner. There is the option to use an overload of Parallel.ForEach which takes a Partitioner<T> instance.  The Partitioner<T> class is an abstract class which allows for both static and dynamic partitioning.  By overriding Partitioner<T>.SupportsDynamicPartitions, you can specify whether a dynamic approach is available.  If not, your custom Partitioner<T> subclass would override GetPartitions(int), which returns a list of IEnumerator<T> instances.  These are then used by the Parallel class to split work up amongst processors.  When dynamic partitioning is available, GetDynamicPartitions() is used, which returns an IEnumerable<T> for each partition.  If you do decide to implement your own Partitioner<T>, keep in mind the goals and tradeoffs of different partitioning strategies, and design appropriately. The Samples for Parallel Programming project includes a ChunkPartitioner class in the ParallelExtensionsExtras project.  This provides example code for implementing your own, custom allocation strategies, including a static allocator of a given chunk size.  Although implementing your own Partitioner<T> is possible, as I mentioned above, this is rarely required or useful in practice.  The default behavior of the TPL is very good, often better than any hand written partitioning strategy.

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