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• How to program critical section for reader-writer systems?

  - by Srinivas Nayak

  Hi, Lets say, I have a reader-writer system where reader and writer are concurrently running. 'a' and 'b' are two shared variables, which are related to each other, so modification to them needs to be an atomic operation. A reader-writer system can be of the following types: rr ww r-w r-ww rr-w rr-ww where [ r : single reader rr: multiple reader w : single writer ww: multiple writer ] Now, We can have a read method for a reader and a write method for a writer as follows. I have written them system type wise. rr read_method { read a; read b; } ww write_method { lock(m); write a; write b; unlock(m); } r-w r-ww rr-w rr-ww read_method { lock(m); read a; read b; unlock(m); } write_method { lock(m); write a; write b; unlock(m); } For multiple reader system, shared variable access doesn't need to be atomic. For multiple writer system, shared variable access need to be atomic, so locked with 'm'. But, for system types 3 to 6, is my read_method and write_method correct? How can I improve? Sincerely, Srinivas Nayak

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• Can I prevent a Linux user space pthread yielding in critical code?

  - by KermitG

  I am working on an user space app for an embedded Linux project using the 2.6.24.3 kernel. My app passes data between two file nodes by creating 2 pthreads that each sleep until a asynchronous IO operation completes at which point it wakes and runs a completion handler. The completion handlers need to keep track of how many transfers are pending and maintain a handful of linked lists that one thread will add to and the other will remove. // sleep here until events arrive or time out expires for(;;) { no_of_events = io_getevents(ctx, 1, num_events, events, &timeout); // Process each aio event that has completed or thrown an error for (i=0; i<no_of_events; i++) { // Get pointer to completion handler io_complete = (io_callback_t) events[i].data; // Get pointer to data object iocb = (struct iocb *) events[i].obj; // Call completion handler and pass it the data object io_complete(ctx, iocb, events[i].res, events[i].res2); } } My question is this... Is there a simple way I can prevent the currently active thread from yielding whilst it runs the completion handler rather than going down the mutex/spin lock route? Or failing that can Linux be configured to prevent yielding a pthread when a mutex/spin lock is held?

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• i just deleted a worksheet that was critical, what do i do now?

  - by every_answer_gets_a_point

  i also saved it is there any way to recover it?

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• Rhythmbox is crashing on start

  - by Kristal

  I'm using ubuntu 10.10 and until about 3 days ago rhythmbox worked fine but now when I start it, it opens, then after 4 second it crashes. When running it from terminal I get this: ~$ rhythmbox (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed ** Message: pygobject_register_sinkfunc is deprecated (GstObject) (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed Segmentation fault and then rhythmbox closes. What to do? =\ Edit: Disabled most of the plugins and it's not crashing now, but i still get when running from terminal (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed ** Message: pygobject_register_sinkfunc is deprecated (GstObject) (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed should I worry?

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• Architect: "Lip Service"

  Meeting enterprise architecture communication challenges is critical.

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• Nagios state transition and event handler issue

  - by Dattatray

  We are using Nagios to check duplicate processes. define service { use local-service host_name xxx service_description xxx Duplicate Processes check_interval 1 max_check_attempts 1 contact_groups admins event_handler restart-dependent-processes check_command check_procs_duplicate!2!3!2!2!2 } check_procs_duplicate checks if there are any duplicate processes and returns the state - e.g. CRITICAL. The event handler kills the duplicate processes and it's dependent processes and starts one instance of the process and dependent process. At the end of this again Nagios checks if there are any duplicate processes and sets the state accordingly - OK/WARNING/CRITICAL. The event handler takes more time to start the processes and during this time if someone manually starts the process, the state will remain in CRITICAL itself. During the next interval, Nagios will again check for duplicate processes and it will find it again CRITICAL. The event handler will not get executed now, as the previos and current both the states are CRITICAL. Any pointers about how to fix this issue?

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• Premature-Optimization and Performance Anxiety

  - by James Michael Hare

  While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about.  After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations.  Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks.  In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process.  At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above.  I'm not talking about valid performance decisions.  There are decisions one should make when designing and writing an application that are valid performance decisions.  Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search).  But these in my mind are macro optimizations.  The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking.  This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it.  I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer.  I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered.  In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance.  This is why in many cases such early code-bases were very hard to maintain.  I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead.  Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications.  Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made.  But I would strongly advice against such optimization because of it's cost.  Many folks that are performing an optimization think it's always a win-win.  That they're simply adding speed to the application, what could possibly be wrong with that?  What they don't realize is the cost of their choice.  For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application.  It will become so fragile over time that maintenance will become a nightmare.  I've seen such applications in places I have worked.  There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance.  Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation).  To me this was almost a joke.  Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety.  The only time twice is really that much slower is when once was too slow to begin with.  Think about it.  2 minutes is slow as a response time because 1 minute is slow.  But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial!  The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations).  To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can.  I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious.  But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization.  I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true.  If you're a beginner, resist the urge to optimize at all costs.  And if you are an expert, delay that decision.  As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient.  Chances are it will be network, database, or disk hits that will be your slow-down, not your code.  As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact.  Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Thread Synchronisation 101

  - by taspeotis

  Previously I've written some very simple multithreaded code, and I've always been aware that at any time there could be a context switch right in the middle of what I'm doing, so I've always guarded access the shared variables through a CCriticalSection class that enters the critical section on construction and leaves it on destruction. I know this is fairly aggressive and I enter and leave critical sections quite frequently and sometimes egregiously (e.g. at the start of a function when I could put the CCriticalSection inside a tighter code block) but my code doesn't crash and it runs fast enough. At work my multithreaded code needs to be a tighter, only locking/synchronising at the lowest level needed. At work I was trying to debug some multithreaded code, and I came across this: EnterCriticalSection(&m_Crit4); m_bSomeVariable = true; LeaveCriticalSection(&m_Crit4); Now, m_bSomeVariable is a Win32 BOOL (not volatile), which as far as I know is defined to be an int, and on x86 reading and writing these values is a single instruction, and since context switches occur on an instruction boundary then there's no need for synchronising this operation with a critical section. I did some more research online to see whether this operation did not need synchronisation, and I came up with two scenarios it did: The CPU implements out of order execution or the second thread is running on a different core and the updated value is not written into RAM for the other core to see; and The int is not 4-byte aligned. I believe number 1 can be solved using the "volatile" keyword. In VS2005 and later the C++ compiler surrounds access to this variable using memory barriers, ensuring that the variable is always completely written/read to the main system memory before using it. Number 2 I cannot verify, I don't know why the byte alignment would make a difference. I don't know the x86 instruction set, but does mov need to be given a 4-byte aligned address? If not do you need to use a combination of instructions? That would introduce the problem. So... QUESTION 1: Does using the "volatile" keyword (implicity using memory barriers and hinting to the compiler not to optimise this code) absolve a programmer from the need to synchronise a 4-byte/8-byte on x86/x64 variable between read/write operations? QUESTION 2: Is there the explicit requirement that the variable be 4-byte/8-byte aligned? I did some more digging into our code and the variables defined in the class: class CExample { private: CRITICAL_SECTION m_Crit1; // Protects variable a CRITICAL_SECTION m_Crit2; // Protects variable b CRITICAL_SECTION m_Crit3; // Protects variable c CRITICAL_SECTION m_Crit4; // Protects variable d // ... }; Now, to me this seems excessive. I thought critical sections synchronised threads between a process, so if you've got one you can enter it and no other thread in that process can execute. There is no need for a critical section for each variable you want to protect, if you're in a critical section then nothing else can interrupt you. I think the only thing that can change the variables from outside a critical section is if the process shares a memory page with another process (can you do that?) and the other process starts to change the values. Mutexes would also help here, named mutexes are shared across processes, or only processes of the same name? QUESTION 3: Is my analysis of critical sections correct, and should this code be rewritten to use mutexes? I have had a look at other synchronisation objects (semaphores and spinlocks), are they better suited here? QUESTION 4: Where are critical sections/mutexes/semaphores/spinlocks best suited? That is, which synchronisation problem should they be applied to. Is there a vast performance penalty for choosing one over the other? And while we're on it, I read that spinlocks should not be used in a single-core multithreaded environment, only a multi-core multithreaded environment. So, QUESTION 5: Is this wrong, or if not, why is it right? Thanks in advance for any responses :)

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• Monitor your Hard Drive’s Health with Acronis Drive Monitor

  - by Matthew Guay

  Are you worried that your computer’s hard drive could die without any warning?  Here’s how you can keep tabs on it and get the first warning signs of potential problems before you actually lose your critical data. Hard drive failures are one of the most common ways people lose important data from their computers.  As more of our memories and important documents are stored digitally, a hard drive failure can mean the loss of years of work.  Acronis Drive Monitor helps you avert these disasters by warning you at the first signs your hard drive may be having trouble.  It monitors many indicators, including heat, read/write errors, total lifespan, and more. It then notifies you via a taskbar popup or email that problems have been detected.  This early warning lets you know ahead of time that you may need to purchase a new hard drive and migrate your data before it’s too late. Getting Started Head over to the Acronis site to download Drive Monitor (link below).  You’ll need to enter your name and email, and then you can download this free tool. Also, note that the download page may ask if you want to include a trial of their for-pay backup program.  If you wish to simply install the Drive Monitor utility, click Continue without adding. Run the installer when the download is finished.  Follow the prompts and install as normal. Once it’s installed, you can quickly get an overview of your hard drives’ health.  Note that it shows 3 categories: Disk problems, Acronis backup, and Critical Events.  On our computer, we had Seagate DiskWizard, an image backup utility based on Acronis Backup, installed, and Acronis detected it. Drive Monitor stays running in your tray even when the application window is closed.  It will keep monitoring your hard drives, and will alert you if there’s a problem. Find Detailed Information About Your Hard Drives Acronis’ simple interface lets you quickly see an overview of how the drives on your computer are performing.  If you’d like more information, click the link under the description.  Here we see that one of our drives have overheated, so click Show disks to get more information. Now you can select each of your drives and see more information about them.  From the Disk overview tab that opens by default, we see that our drive is being monitored, has been running for a total of 368 days, and that it’s health is good.  However, it is running at 113F, which is over the recommended max of 107F.   The S.M.A.R.T. parameters tab gives us more detailed information about our drive.  Most users wouldn’t know what an accepted value would be, so it also shows the status.  If the value is within the accepted parameters, it will report OK; otherwise, it will show that has a problem in this area. One very interesting piece of information we can see is the total number of Power-On Hours, Start/Stop Count, and Power Cycle Count.  These could be useful indicators to check if you’re considering purchasing a second hand computer.  Simply load this program, and you’ll get a better view of how long it’s been in use. Finally, the Events tab shows each time the program gave a warning.  We can see that our drive, which had been acting flaky already, is routinely overheating even when our other hard drive was running in normal temperature ranges. Monitor Acronis Backups And Critical Errors In addition to monitoring critical stats of your hard drives, Acronis Drive Monitor also keeps up with the status of your backup software and critical events reported by Windows.  You can access these from the front page, or via the links on the left hand sidebar.  If you have any edition of any Acronis Backup product installed, it will show that it was detected.  Note that it can only monitor the backup status of the newest versions of Acronis Backup and True Image. If no Acronis backup software was installed, it will show a warning that the drive may be unprotected and will give you a link to download Acronis backup software.   If you have another backup utility installed that you wish to monitor yourself, click Configure backup monitoring, and then disable monitoring on the drives you’re monitoring yourself. Finally, you can view any detected Critical events from the Critical events tab on the left. Get Emailed When There’s a Problem One of Drive Monitor’s best features is the ability to send you an email whenever there’s a problem.  Since this program can run on any version of Windows, including the Server and Home Server editions, you can use this feature to stay on top of your hard drives’ health even when you’re not nearby.  To set this up, click Options in the top left corner. Select Alerts on the left, and then click the Change settings link to setup your email account. Enter the email address which you wish to receive alerts, and a name for the program.  Then, enter the outgoing mail server settings for your email.  If you have a Gmail account, enter the following information: Outgoing mail server (SMTP): smtp.gmail.com Port: 587 Username and Password: Your gmail address and password Check the Use encryption box, and then select TLS from the encryption options.   It will now send a test message to your email account, so check and make sure it sent ok. Now you can choose to have the program automatically email you when warnings and critical alerts appear, and also to have it send regular disk status reports.   Conclusion Whether you’ve got a brand new hard drive or one that’s seen better days, knowing the real health of your it is one of the best ways to be prepared before disaster strikes.  It’s no substitute for regular backups, but can help you avert problems.  Acronis Drive Monitor is a nice tool for this, and although we wish it wasn’t so centered around their backup offerings, we still found it a nice tool. Link Download Acronis Drive Monitor (registration required) Similar Articles Productive Geek Tips Quick Tip: Change Monitor Timeout From Command LineAnalyze and Manage Hard Drive Space with WinDirStatMonitor CPU, Memory, and Disk IO In Windows 7 with Taskbar MetersDefrag Multiple Hard Drives At Once In WindowsFind Your Missing USB Drive on Windows XP TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips HippoRemote Pro 2.2 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Windows 7’s WordPad is Actually Good Greate Image Viewing and Management with Zoner Photo Studio Free Windows Media Player Plus! – Cool WMP Enhancer Get Your Team’s World Cup Schedule In Google Calendar Backup Drivers With Driver Magician TubeSort: YouTube Playlist Organizer

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• Implications of Java 6 End of Public Updates for EBS Users

  - by Steven Chan (Oracle Development)

  The Support Roadmap for Oracle Java is published here: Oracle Java SE Support Roadmap The latest updates to that page (as of Sept. 19, 2012) state (emphasis added): Java SE 6 End of Public Updates Notice After February 2013, Oracle will no longer post updates of Java SE 6 to its public download sites. Existing Java SE 6 downloads already posted as of February 2013 will remain accessible in the Java Archive on Oracle Technology Network. Developers and end-users are encouraged to update to more recent Java SE versions that remain available for public download. For enterprise customers, who need continued access to critical bug fixes and security fixes as well as general maintenance for Java SE 6 or older versions, long term support is available through Oracle Java SE Support . What does this mean for Oracle E-Business Suite users? EBS users fall under the category of "enterprise users" above.  Java is an integral part of the Oracle E-Business Suite technology stack, so EBS users will continue to receive Java SE 6 updates after February 2013. In other words, nothing will change for EBS users after February 2013.  EBS users will continue to receive critical bug fixes and security fixes as well as general maintenance for Java SE 6. These Java SE 6 updates will be made available to EBS users for the Extended Support periods documented in the Oracle Lifetime Support policy document for Oracle Applications (PDF): EBS 11i Extended Support ends November 2013 EBS 12.0 Extended Support ends January 2015 EBS 12.1 Extended Support ends December 2018 Will EBS users be forced to upgrade to JRE 7 for Windows desktop clients? No. This upgrade will be highly recommended but currently remains optional. JRE 6 will be available to Windows users to run with EBS for the duration of your respective EBS Extended Support period.  Updates will be delivered via My Oracle Support, where you can continue to receive critical bug fixes and security fixes as well as general maintenance for JRE 6 desktop clients.  The certification of Oracle E-Business Suite with JRE 7 (for desktop clients accessing EBS Forms-based content) is in its final stages.  If you plan to upgrade your EBS desktop clients to JRE 7 when that certification is released, you can get a head-start on that today. Coexistence of JRE 6 and JRE 7 on Windows desktops The upgrade to JRE 7 will be highly recommended for EBS users, but some users may need to run both JRE 6 and 7 on their Windows desktops for reasons unrelated to the E-Business Suite. Most EBS configurations with IE and Firefox use non-static versioning by default. JRE 7 will be invoked instead of JRE 6 if both are installed on a Windows desktop. For more details, see "Appendix B: Static vs. Non-static Versioning and Set Up Options" in Notes 290801.1 and 393931.1. Applying Updates to JRE 6 and JRE 7 to Windows desktops Auto-update will keep JRE 7 up-to-date for Windows users with JRE 7 installed. Auto-update will only keep JRE 7 up-to-date for Windows users with both JRE 6 and 7 installed.  JRE 6 users are strongly encouraged to apply the latest Critical Patch Updates as soon as possible after each release. The Jave SE CPUs will be available via My Oracle Support.  EBS users can find more information about JRE 6 and 7 updates here: Information Center: Installation & Configuration for Oracle Java SE (Note 1412103.2) The dates for future Java SE CPUs can be found on the Critical Patch Updates, Security Alerts and Third Party Bulletin.  An RSS feed is available on that site for those who would like to be kept up-to-date. What will Mac users need? Oracle will provide updates to JRE 7 for Mac OS X users. EBS users running Macs will need to upgrade to JRE 7 to receive JRE updates. The certification of Oracle E-Business Suite with JRE 7 for Mac-based desktop clients accessing EBS Forms-based content is underway. Mac users waiting for that certification may find this article useful: How to Reenable Apple Java 6 Plug-in for Mac EBS Users Will EBS users be forced to upgrade to JDK 7 for EBS application tier servers? No. This upgrade will be highly recommended but will be optional for EBS application tier servers running on Windows, Linux, and Solaris.  You can choose to remain on JDK 6 for the duration of your respective EBS Extended Support period.  If you remain on JDK 6, you will continue to receive critical bug fixes and security fixes as well as general maintenance for JDK 6. The certification of Oracle E-Business Suite with JDK 7 for EBS application tier servers on Windows, Linux, and Solaris as well as other platforms such as IBM AIX and HP-UX is planned.  Customers running platforms other than Windows, Linux, and Solaris should refer to their Java vendors's sites for more information about their support policies. Related Articles Planning Bulletin for JRE 7: What EBS Customers Can Do Today EBS 11i and 12.1 Support Timeline Changes Frequently Asked Questions about Latest EBS Support Changes Critical Patch Updates During EBS 11i Exception to Sustaining Support Period

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• Performance and Optimization Isn’t Evil

  - by Reed

  Donald Knuth is a fairly amazing guy.  I consider him one of the most influential contributors to computer science of all time.  Unfortunately, most of the time I hear his name, I cringe.  This is because it’s typically somebody quoting a small portion of one of his famous statements on optimization: “premature optimization is the root of all evil.” I mention that this is only a portion of the entire quote, and, as such, I feel that Knuth is being quoted out of context.  Optimization is important.  It is a critical part of every software development effort, and should never be ignored.  A developer who ignores optimization is not a professional.  Every developer should understand optimization – know what to optimize, when to optimize it, and how to think about code in a way that is intelligent and productive from day one. I want to start by discussing my own, personal motivation here.  I recently wrote about a performance issue I ran across, and was slammed by multiple comments and emails that effectively boiled down to: “You’re an idiot.  Premature optimization is the root of all evil.  This doesn’t matter.”  It didn’t matter that I discovered this while measuring in a profiler, and that it was a portion of my code base that can take “many hours to complete.”  Even so, multiple people instantly jump to “it’s premature – it doesn’t matter.” This is a common thread I see.  For example, StackOverflow has many pages of posts with answers that boil down to (mis)quoting Knuth.  In fact, just about any question relating to a performance related issue gets this quote thrown at it immediately – whether it deserves it or not.  That being said, I did receive some positive comments and emails as well.  Many people want to understand how to optimize their code, approaches to take, tools and techniques they can use, and any other advice they can discover. First, lets get back to Knuth – I mentioned before that Knuth is being quoted out of context.  Lets start by looking at the entire quote from his 1974 paper Structured Programming with go to Statements: “We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%. A good programmer will not be lulled into complacency by such reasoning, he will be wise to look carefully at the critical code; but only after that code has been identified.” Ironically, if you read Knuth’s original paper, this statement was made in the middle of a discussion of how Knuth himself had changed how he approaches optimization.  It was never a statement saying “don’t optimize”, but rather, “optimizing intelligently provides huge advantages.”  His approach had three benefits: “a) it doesn’t take long” … “b) the payoff is real”, c) you can “be less efficient in the other parts of my programs, which therefore are more readable and more easily written and debugged.” Looking at Knuth’s premise here, and reading that section of his paper, really leads to a few observations: Optimization is important  “he will be wise to look carefully at the critical code” Normally, 3% of your code – three lines out of every 100 you write, are “critical code” and will require some optimization: “we should not pass up our opportunities in that critical 3%” Optimization, if done well, should not be time consuming: “it doesn’t take long” Optimization, if done correctly, provides real benefits: “the payoff is real” None of this is new information.  People who care about optimization have been discussing this for years – for example, Rico Mariani’s Designing For Performance (a fantastic article) discusses many of the same issues very intelligently. That being said, many developers seem unable or unwilling to consider optimization.  Many others don’t seem to know where to start.  As such, I’m going to spend some time writing about optimization – what is it, how should we think about it, and what can we do to improve our own code.

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• i don't receive mail notification...Nagios Core 4

  - by alessio

  I have a problem with automatically mail notification in Nagios Core 4 installed on ubuntu 12 .04 lts server... i have tried to send mail with nagios user and root user with the command: echo "test" | mail -s "test mail" [email protected] and i received mail correctly... but i don't receive any automatically mail notification... i don't know how can i do to resolve this issue! :( these are my configuration files (commands.cfg, contacts.cfg, nagios.log, mail.log): commands.cfg (the path /usr/bin/mail is the right path): # 'notify-host-by-email' command definition define command{ command_name notify-host-by-email command_line /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $HOSTOUTPUT$\n\nDate/Time: $LONGDATETIME$\n" | /usr/bin/mail -s "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is $HOSTSTATE$ **" $CONTACTEMAIL$ } # 'notify-service-by-email' command definition define command{ command_name notify-service-by-email command_line /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$SERVICEOUTPUT$\n" | /usr/bin/mail -s "** $NOTIFICATIONTYPE$ Service Alert: $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **" $CONTACTEMAIL$ } # 'process-host-perfdata' command definition define command{ command_name process-host-perfdata command_line /usr/bin/printf "%b" "$LASTHOSTCHECK$\t$HOSTNAME$\t$HOSTSTATE$\t$HOSTATTEMPT$\t$HOSTSTATETYPE$\t$HOSTEXECUTIONTIME$\t$HOSTOUTPUT$\t$HOSTPERFDATA$\n" >> /usr/local/nagios/var/host-perfdata.out } # 'process-service-perfdata' command definition define command{ command_name process-service-perfdata command_line /usr/bin/printf "%b" "$LASTSERVICECHECK$\t$HOSTNAME$\t$SERVICEDESC$\t$SERVICESTATE$\t$SERVICEATTEMPT$\t$SERVICESTATETYPE$\t$SERVICEEXECUTIONTIME$\t$SERVICELATENCY$\t$SERVICEOUTPUT$\t$SERVICEPERFDATA$\n" >> /usr/local/nagios/var/service-perfdata.out } contacts.cfg: define contact{ contact_name supporto alias Supporto Clienti DEA service_notification_period 24x7 host_notification_period 24x7 service_notification_options w,u,c,r host_notification_options d,r service_notification_commands notify-service-by-email host_notification_commands notify-host-by-email email [email protected] } define contactgroup{ contactgroup_name admins alias Nagios Administrators members supporto } nagios.log: [1401871412] SERVICE ALERT: fileserver;Current Users;OK;SOFT;2;USERS OK - 1 users currently logged in [1401871953] SERVICE ALERT: backups;Nagios Status;WARNING;SOFT;1;NAGIOS WARNING: 36 processes, status log updated 541 seconds ago [1401872133] SERVICE ALERT: backups;Nagios Status;OK;SOFT;2;NAGIOS OK: 36 processes, status log updated 180 seconds ago [1401872321] SERVICE ALERT: posta;Swap Usage;CRITICAL;SOFT;1;CRITICAL - Plugin timed out after 10 seconds [1401872322] SERVICE ALERT: fileserver;Current Users;CRITICAL;SOFT;1;CRITICAL - Plugin timed out after 10 seconds [1401872420] SERVICE ALERT: archivio;Disk Space;CRITICAL;SOFT;1;CRITICAL - Plugin timed out after 10 seconds [1401872492] SERVICE ALERT: fileserver;Current Users;OK;SOFT;2;USERS OK - 1 users currently logged in [1401872492] SERVICE ALERT: posta;Swap Usage;OK;SOFT;2;SWAP OK: 100% free (1984 MB out of 1984 MB) [1401872590] SERVICE ALERT: archivio;Disk Space;OK;SOFT;2;DISK OK [1401872931] Auto-save of retention data completed successfully. [1401873333] SERVICE ALERT: backups;Nagios Status;WARNING;SOFT;1;NAGIOS WARNING: 36 processes, status log updated 402 seconds ago [1401873513] SERVICE ALERT: backups;Nagios Status;OK;SOFT;2;NAGIOS OK: 36 processes, status log updated 180 seconds ago mail.log (i think that the problem is here but i don't know how to resolve it): Jun 4 10:00:01 backups sm-msp-queue[6109]: My unqualified host name (backups) unknown; sleeping for retry Jun 4 10:01:01 backups sm-msp-queue[6109]: unable to qualify my own domain name (backups) -- using short name Jun 4 10:20:01 backups sm-msp-queue[7247]: My unqualified host name (backups) unknown; sleeping for retry Jun 4 10:21:01 backups sm-msp-queue[7247]: unable to qualify my own domain name (backups) -- using short name Jun 4 10:40:01 backups sm-msp-queue[8327]: My unqualified host name (backups) unknown; sleeping for retry Jun 4 10:41:01 backups sm-msp-queue[8327]: unable to qualify my own domain name (backups) -- using short name Jun 4 11:00:01 backups sm-msp-queue[9549]: My unqualified host name (backups) unknown; sleeping for retry Jun 4 11:01:01 backups sm-msp-queue[9549]: unable to qualify my own domain name (backups) -- using short name Jun 4 11:20:01 backups sm-msp-queue[10678]: My unqualified host name (backups) unknown; sleeping for retry Jun 4 11:21:01 backups sm-msp-queue[10678]: unable to qualify my own domain name (backups) -- using short name i'm at the last step and i want to finish this Nagios Core! :) Any help be appreciate!:) host definition (this host have the disk almost full and it is in hard state but non notification) : define host{ use generic-host ; Name of host template to use host_name posta alias Server Posta ESA address 10.10.2.102 parents xen1, xen2 icon_image redhat.png statusmap_image redhat.gd2 } service definition: define service{ use generic-service host_name xen1, maestro, xen2, posta, nas002, serv2, esasrvmi02, esaubuntumi service_description Disk Space check_command ssh_all_disks!10%!5% } Notification is allowed for the contact definition you gave, but is it also allowed at the the service level ? sorry but i don't understand this thing! :(

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• Twice as long and half as long

  - by PointsToShare

  We are in a project and we hit some snags. What’s a snag? An activity that takes longer than expected. Actually it takes longer than the time assigned to it by an over pressed PM who accepts an impossible time table and tries his best to make it possible, but I digress (again!).  So we have snags and we also have the opposite. Let’s call these “cinches”. The question is: how does a combination of snags and cinches affect the project timeline? Well, there is no simple answer. It depends on the projects dependencies as we see in the PERT chart. If all the snags are in the critical path and all the cinches are elsewhere then the cinches don’t help at all. In fact any snag in the critical path will delay the project.  Conversely, a cinch in the critical path will expedite it. A snag outside the critical path might be serious enough to even change the critical path. Thus without the PERT chart, we cannot really tell. Still there is a principle involved – Time and speed are non-linear! Twice as long adds a full unit, half as long only takes ½ unit away. Let’s just investigate a simple project. It consists of two activities – S and C - each estimated to take a week. Alas, S is a snag and really needs twice the time allotted and – a sigh of relief – C is a cinch and will take half the time allotted, so everything is Hun-key-dory, or is it?  Even here the PERT chart is important. We have 2 cases: 1: S depends on C (or vice versa) as in when the two activities are assigned to one employee. Here the estimated time was 1 + 1 and the actual time was 2 + ½ and we are ½ week late or 25% late. 2: S and C are done in parallel. Here the estimated time was 1, but the actual time is 2 – we are a whole week or 100% late. Let’s change the equation a little. S need 1.5 and C needs .5 so in case 1, we have the loss fully compensated by the gain, but in case 2 we are still behind. There are cases where this really makes no difference. This is when the critical path is not affected and we have enough slack in the other paths to counteract the difference between its snags and cinches – Let’s call this difference DSC. So if the slack is greater than DSC the project will not suffer. Conclusion: There is no general rule about snags and cinches. We need to examine each case within its project, still as we saw in the 4 examples above; the snag is generally more powerful than the cinch. Long live Murphy! That’s All Folks

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• October 2013 Fusion Middleware (FMW) Proactive Patches released

  - by Irina

  We are glad to announce that the following Fusion Middleware (FMW) Proactive  patches were released on October 15, 2013.Bundle PatchesBundle patches are collections of controlled, well tested critical bug fixes for a specific product  which may include security contents and occasionally minor enhancements. These are cumulative in nature meaning the latest bundle patch in a particular series includes the contents of the previous bundle patches released.  A suite bundle patch is an aggregation of multiple product  bundle patches that are part of a product suite. Oracle Identity Management Suite Bundle Patch 11.1.1.5.5 consisting of Oracle Identity Manager (OIM) 11.1.1.5.9 bundle patch Oracle Access Manager (OAM) 11.1.1.5.6 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.1.5.2 bundle patch. Oracle Entitlement Server (OES) 11.1.1.5.4 bundle patch. Oracle Identity Management Suite Bundle Patch 11.1.2.0.4 consisting of Oracle Access Manager (OAM) 11.1.2.0.4 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.2.0.2 bundle patch. Oracle Entitlement Server (OES) 11.1.2.0.2 bundle patch. Oracle Identity Analytics (OIA ) 11.1.1.5.6  bundle patch. Oracle GlassFish Server (OGFS) 2.1.1.22, 3.0.1.8 and 3.1.2.7 bundle patches. Oracle iPlanet Web Server (OiWS) 7.0.18 bundle patch Oracle SOA Suite (SOA) 11.1.1.7.1 bundle patch Oracle WebCenter Portal (WCP) 11.1.1.8.1 bundle patch Sun Role Manager (SRM) 4.1.7 and 5.0.3.2 bundle patches. Patch Set Updates (PSU)Patch Set Updates (PSU)  are collections of well controlled, well tested critical bug fixes for a specific product  that have been proven in customer environments. PSUs  may include security contents but no  enhancements are included. These are cumulative in nature meaning the latest PSU  in a particular series includes the contents of the previous PSUs  released. Oracle Exalogic 2.0.3.0.4 Physical Linux x86-64 and 2.0.4.0.4 Physical Solaris x86-64 PSUs. Oracle WebLogic Server 10.3.6.0.6 and 12.1.1.0.6 PSUs. Critical Patch Update (CPU)The Critical Patch Update program is Oracle's quarterly release of security fixes.The following additional patches were released as part of Oracle's Critical Patch Update program: Oracle JDeveloper 11.1.2.3.0, 11.1.2.4.0 and 12.1.2.0.0 Oracle Outside In Technology 8.4.0 and  8.4.1 Oracle Portal 11.1.1.6.0 Oracle Security Service  11.1.1.6.0, 11.1.1.7.0 and 12.1.2.0.0 Oracle WebCache 11.1.1.6.0 and 11.1.1.7.0 Oracle WebCenter Content 10.1.3.5.1, 11.1.1.6.0, 11.1.1.7.0 and 11.1.1.8.0 Oracle WebServices 10.1.3.5.0 and 11.1.1.6.0 For more information: Master Notes on Fusion Middleware Proactive Patching PSU and CPU October 2013  Availability Document Critical Patch Update Advisory -  October 2013

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• October 2013 FMW Proactive Patches Released

  - by mustafakaya

  The following Fusion Middleware (FMW) Proactive  patches were released on October 15, 2013. Bundle Patches : Bundle patches are collections of controlled, well tested critical bug fixes for a specific product  which may include security contents and occasionally minor enhancements. These are cumulative in nature meaning the latest bundle patch in a particular series includes the contents of the previous bundle patches released.  A suite bundle patch is an aggregation of multiple product  bundle patches that are part of a product suite. Oracle Identity Management Suite Bundle Patch 11.1.1.5.5 consisting of Oracle Identity Manager (OIM) 11.1.1.5.9 bundle patch Oracle Access Manager (OAM) 11.1.1.5.6 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.1.5.2 bundle patch. Oracle Entitlement Server (OES) 11.1.1.5.4 bundle patch. Oracle Identity Management Suite Bundle Patch 11.1.2.0.4 consisting of Oracle Access Manager (OAM) 11.1.2.0.4 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.2.0.2 bundle patch. Oracle Entitlement Server (OES) 11.1.2.0.2 bundle patch. Oracle Identity Analytics (OIA ) 11.1.1.5.6  bundle patch. Oracle GlassFish Server (OGFS) 2.1.1.22, 3.0.1.8 and 3.1.2.7 bundle patches. Oracle iPlanet Web Server (OiWS) 7.0.18 bundle patch Oracle SOA Suite (SOA) 11.1.1.7.1 bundle patch Oracle WebCenter Portal (WCP) 11.1.1.8.1 bundle patch Sun Role Manager (SRM) 4.1.7 and 5.0.3.2 bundle patches. Patch Set Updates (PSU) Patch Set Updates (PSU)  are collections of well controlled, well tested critical bug fixes for a specific product  that have been proven in customer environments. PSUs  may include security contents but no  enhancements are included. These are cumulative in nature meaning the latest PSU  in a particular series includes the contents of the previous PSUs  released.  Oracle Exalogic 2.0.3.0.4 Physical Linux x86-64 and 2.0.4.0.4 Physical Solaris x86-64 PSUs. Oracle WebLogic Server 10.3.6.0.6 and 12.1.1.0.6 PSUs. Critical Patch Update (CPU) : The Critical Patch Update program is Oracle's quarterly release of security fixes. The following additional patches were released as part of Oracle's Critical Patch Update program: Oracle JDeveloper 11.1.2.3.0, 11.1.2.4.0 and 12.1.2.0.0 Oracle Outside In Technology 8.4.0 and  8.4.1 Oracle Portal 11.1.1.6.0 Oracle Security Service  11.1.1.6.0, 11.1.1.7.0 and 12.1.2.0.0 Oracle WebCache 11.1.1.6.0 and 11.1.1.7.0 Oracle WebCenter Content 10.1.3.5.1, 11.1.1.6.0, 11.1.1.7.0 and 11.1.1.8.0 Oracle WebServices 10.1.3.5.0 and 11.1.1.6.0 For more information; Master Notes on Fusion Middleware Proactive Patching. PSU and CPU October 2013  Availability Document Critical Patch Update Advisory -  October 2013 

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• October 2013 Fusion Middleware (FMW) Proactive Patches released

  - by PCat

  We are glad to announce that the following Fusion Middleware (FMW) Proactive  patches were released on October 15, 2013.Bundle PatchesBundle patches are collections of controlled, well tested critical bug fixes for a specific product  which may include security contents and occasionally minor enhancements. These are cumulative in nature meaning the latest bundle patch in a particular series includes the contents of the previous bundle patches released.  A suite bundle patch is an aggregation of multiple product  bundle patches that are part of a product suite. Oracle Identity Management Suite Bundle Patch 11.1.1.5.5 consisting of Oracle Identity Manager (OIM) 11.1.1.5.9 bundle patch Oracle Access Manager (OAM) 11.1.1.5.6 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.1.5.2 bundle patch. Oracle Entitlement Server (OES) 11.1.1.5.4 bundle patch. Oracle Identity Management Suite Bundle Patch 11.1.2.0.4 consisting of Oracle Access Manager (OAM) 11.1.2.0.4 bundle patch. Oracle Adaptive Access Manager (OAAM) 11.1.2.0.2 bundle patch. Oracle Entitlement Server (OES) 11.1.2.0.2 bundle patch. Oracle Identity Analytics (OIA ) 11.1.1.5.6  bundle patch. Oracle GlassFish Server (OGFS) 2.1.1.22, 3.0.1.8 and 3.1.2.7 bundle patches. Oracle iPlanet Web Server (OiWS) 7.0.18 bundle patch Oracle SOA Suite (SOA) 11.1.1.7.1 bundle patch Oracle WebCenter Portal (WCP) 11.1.1.8.1 bundle patch Sun Role Manager (SRM) 4.1.7 and 5.0.3.2 bundle patches. Patch Set Updates (PSU)Patch Set Updates (PSU)  are collections of well controlled, well tested critical bug fixes for a specific product  that have been proven in customer environments. PSUs  may include security contents but no  enhancements are included. These are cumulative in nature meaning the latest PSU  in a particular series includes the contents of the previous PSUs  released. Oracle Exalogic 2.0.3.0.4 Physical Linux x86-64 and 2.0.4.0.4 Physical Solaris x86-64 PSUs. Oracle WebLogic Server 10.3.6.0.6 and 12.1.1.0.6 PSUs. Critical Patch Update (CPU)The Critical Patch Update program is Oracle's quarterly release of security fixes.The following additional patches were released as part of Oracle's Critical Patch Update program: Oracle JDeveloper 11.1.2.3.0, 11.1.2.4.0 and 12.1.2.0.0 Oracle Outside In Technology 8.4.0 and  8.4.1 Oracle Portal 11.1.1.6.0 Oracle Security Service  11.1.1.6.0, 11.1.1.7.0 and 12.1.2.0.0 Oracle WebCache 11.1.1.6.0 and 11.1.1.7.0 Oracle WebCenter Content 10.1.3.5.1, 11.1.1.6.0, 11.1.1.7.0 and 11.1.1.8.0 Oracle WebServices 10.1.3.5.0 and 11.1.1.6.0 For more information: Master Notes on Fusion Middleware Proactive Patching PSU and CPU October 2013  Availability Document Critical Patch Update Advisory -  October 2013

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• launch eclipse,and an error occurs.

  - by chillwarmoon

  environment: Ubuntu 9.10 Eclipse eclipse-jee-galileo-SR2-linux-gtk When I login the ubuntu,and run the eclipse, it works. but when I changed to root user and then launch eclipse,there is an error occurs: (eclipse:5632): GLib-GObject-WARNING **: invalid (NULL) pointer instance (eclipse:5632): GLib-GObject-CRITICAL **: g_signal_connect_data: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed (eclipse:5632): Gtk-CRITICAL **: gtk_settings_get_for_screen: assertion `GDK_IS_SCREEN (screen)' failed (eclipse:5632): Gtk-WARNING **: Screen for GtkWindow not set; you must always set a screen for a GtkWindow before using the window (eclipse:5632): Gtk-WARNING **: Screen for GtkWindow not set; you must always set a screen for a GtkWindow before using the window (eclipse:5632): Gdk-CRITICAL **: gdk_screen_get_display: assertion `GDK_IS_SCREEN (screen)' failed (eclipse:5632): Gdk-CRITICAL **: gdk_display_get_pointer: assertion `GDK_IS_DISPLAY (display)' failed (eclipse:5632): Gtk-WARNING **: Screen for GtkWindow not set; you must always set a screen for a GtkWindow before using the window (eclipse:5632): Gdk-CRITICAL **: gdk_screen_get_n_monitors: assertion `GDK_IS_SCREEN (screen)' failed (eclipse:5632): Gtk-WARNING **: Screen for GtkWindow not set; you must always set a screen for a GtkWindow before using the window (eclipse:5632): Gdk-CRITICAL **: get_monitor: assertion `GDK_IS_SCREEN (screen)' failed Segmentation fault But when I login in Ubuntu as root, and run eclipse, it is ok. I changed to another non-root user,there is an error too. How to deal with this problem. I am looking forward to your reply. thanks.

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• Sorry For The Short Notice! November Deep Dive Demo Invitations

  - by KemButller

  If you would like to get a deep dive overview and demo of two of JD Edwards hottest products in the privacy of your own office, you are in luck!  The Oracle sales team invites you to attend their on-line seminars covering EnterpriseOne One View Reporting and EnterpriseOne Health and Safety Incident Management. You can get the details and register via these links. EnterpriseOne One View Reporting - November 13  EnterpriseOne Health and Safety Incident Management - November 20 

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• ??????????????????????(????)?????

  - by mamoru.kobayashi

  ??????????????????????????????????? ?????????????Oracle Argus Safety Japan 6.0??????????? ??????????2010??????????????????????? ?????????????????????????????????????? ??????? ???????Oracle Argus Safety Japan 6.0??? ????????????????????????????????? ??????????????????????????????????? ???????????????????????????????????? ???????????????????????????????????????? ?????????????????

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• Unable to delete a file using bash script

  - by user3719091

  I'm having problems removing a file in a bash script. I saw the other post with the same problem but none of those solutions solved my problem. The bash script is an OP5 surveillance check and it calls an Expect process that saves a temporary file to the local drive which the bash script reads from. Once it has read the file and checked its status I would like to remove the temporary file. I'm pretty new to scripting so my script may not be as optimal as it can be. Either way it does the job except removing the file once it's done. I will post the entire code below: #!/bin/bash #GET FLAGS while getopts H:c:w: option do case "${option}" in H) HOSTADDRESS=${OPTARG};; c) CRITICAL=${OPTARG};; w) WARNING=${OPTARG};; esac done ./expect.vpn.check.sh $HOSTADDRESS #VARIABLES VPNCount=$(grep -o '[0-9]\+' $HOSTADDRESS.op5.vpn.results) # Check if the temporary results file exists if [ -f $HOSTADDRESS.op5.vpn.results ] then # If the file exist, Print "File Found" message echo Temporary results file exist. Analyze results. else # If the file does NOT exist, print "File NOT Found" message and send message to OP5 echo Temporary results file does NOT exist. Unable to analyze. # Exit with status Critical (exit code 2) exit 2 fi if [[ "$VPNCount" > $CRITICAL ]] then # If the amount of tunnels exceeds the critical threshold, echo out a warning message and current threshold and send warning to OP5 echo "The amount of VPN tunnels exceeds the critical threshold - ($VPNCount)" # Exit with status Critical (exit code 2) exit 2 elif [[ "$VPNCount" > $WARNING ]] then # If the amount of tunnels exceeds the warning threshold, echo out a warning message and current threshold and send warning to OP5 echo "The amount of VPN tunnels exceeds the warning threshold - ($VPNCount)" # Exit with status Warning (exit code 1) exit 1 else # The amount of tunnels do not exceed the warning threshold. # Print an OK message echo OK - $VPNCount # Exit with status OK exit 0 fi #Clean up temporary files. rm -f $HOSTADDRESS.op5.vpn.results I have tried the following solutions: Create a separate variable called TempFile that specifies the file. And specify that in the rm command. I tried creating another if statement similar to the one I use to verify that file exist and then rm the filename. I tried adding the complete name of the file (no variables, just plain text of the file) I can: Remove the file using the full name in both a separate script and directly in the CLI. Is there something in my script that locks the file that prevents me from removing it? I'm not sure what to try next. Thanks in advance!

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• DIR $file "File Not Found" vs DIR $filedir shows it....not permissions, not USB

  - by Kev

  I was having this problem before on a USB drive, but now it's happening on my main RAID5-backed hard disk: 2013-10-17 9:37 C:\>dir "C:\Shares\Shared\Reference\Safety Management System\Vid eo CD\AutoPlay\Docs\Manuel*" Volume in drive C has no label. Volume Serial Number is 3C18-E114 Directory of C:\Shares\Shared\Reference\Safety Management System\Video CD\AutoP lay\Docs 2003-09-09 11:29 PM 1,056,768 Manuel d'intervention d'urgence MFC.doc 2004-06-20 10:36 PM 139,849 Manuel d'intervention d'urgence MFC.pdf 2 File(s) 1,196,617 bytes 0 Dir(s) 196,068,691,968 bytes free 2013-10-17 9:38 C:\>dir "C:\Shares\Shared\Reference\Safety Management System\Vid eo CD\AutoPlay\Docs\Manuel d'intervention d'urgence MFC.doc" Volume in drive C has no label. Volume Serial Number is 3C18-E114 Directory of C:\Shares\Shared\Reference\Safety Management System\Video CD\AutoP lay\Docs File Not Found 2013-10-17 9:38 C:\> This is from a Command Prompt window where I went to Properties and told it I wanted to modify who it ran as. I opened it, had it run as me with the "restricted access" unchecked, then ran the above. The file in question has the following ACLs: Administrators, SYSTEM, and OurCompanyUsers. All three have full control of everything. Nobody has any Deny bits set. I am a member of Administrators. So I don't believe it's a permissions issue. It's not a USB drive, so this time there is no question of USB hardware. Windows Server 2003 Standard Edition SP2. What does this mean? Is this more likely a hardware or software problem?

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• Nagios DNX plugins

  - by danneh3826

  I'm toying with the idea of multiple Nagios instances setup to monitor our infrastructure. I've looked at all the various methods of distributed Nagios checks, and I think DNX comes out the closest. DNX handles failure of worker nodes, that's fine. What happens if the main DNX server fails though? Is there a way to replicate the server too? I'm using AWS EC2 primarily, so I can utilise Elastic Load Balancing for the web UI, but I need to be able to handle the AZ where the monitoring server is to fail over, and essentially for a second to pick up the checking load (active/passive, active/active, so long as it doesn't fail completely) The other thing I'm trying to solve is an issue with routing. What I'd like is to have multiple nodes report a fault before Nagios confirms it as critical. Not the NRPE checks, as they're pretty self explanitory, but things more like check_ping. I often have routing issues out of AWS to certain datacenters, so Nagios can often report bad/no ping/timeout as a critical issue, even though the machine in question is working fine. Would it be possible to have a setup where a worker complains a service check is critical, and have a second worker node (positioned in another datacenter/AZ) also report the service as critical before the Nagios central server issues a critical alert? I realise I might be asking a bit much (how far down the line do you go setting up failover systems before it starts to get ridiculous), however surely someone must have thought of this scenario when developing DNX?

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• Nagios: turn off service checks/display on down hosts

  - by Alien Life Form

  I want to to tweak nagios in such a way that all checking stops (with services not displayed, or displayed as unknown) for any down node. Said differently I only want to see one alert for a down host instead of 1 (down) + n (1 for every service). Note that I am interested in service display/status, not only in turning off notifications. Rationale: we use the nagios firefox/chrome plugin to monitor status and nagios' behavior is too noisy giving readings like these (because every node has 20 services): 3 down, 1 unreachable, 4 warnings, 87 critical This means that the 7 critical services on up node (the problem is on the service) are swamped in a slab of red services which are critical only because they sit on a node that's down/unreachable. What I'd rather like to see is: 3 down, 1 unreachable, 80 unknown, 4 warnings, 7 critical Or even 3 down, 1 unreachable, 4 warnings, 7 critical I have looked in service dependencies but I did not fine a way to describe: "make all services on a alive-host dependen on the status of the host check". I found the problem discussed here, where one of the participants thought it was a nagios bug, and here where one of the participants thought it was "as designed". As things are, I am just interested in the effect, much less in the design philosophy. Note that this nagios is checking hundreds of nodes, so the maintainablilty of the solution is also important. TIA and cheers.

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