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  • SQL SERVER – IO_COMPLETION – Wait Type – Day 10 of 28

    - by pinaldave
    For any good system three things are vital: CPU, Memory and IO (disk). Among these three, IO is the most crucial factor of SQL Server. Looking at real-world cases, I do not see IT people upgrading CPU and Memory frequently. However, the disk is often upgraded for either improving the space, speed or throughput. Today we will look at an IO-related wait types. From Book On-Line: Occurs while waiting for I/O operations to complete. This wait type generally represents non-data page I/Os. Data page I/O completion waits appear as PAGEIOLATCH_* waits. IO_COMPLETION Explanation: Any tasks are waiting for I/O to finish. This is a good indication that IO needs to be looked over here. Reducing IO_COMPLETION wait: When it is an issue concerning the IO, one should look at the following things related to IO subsystem: Proper placing of the files is very important. We should check the file system for proper placement of files – LDF and MDF on a separate drive, TempDB on another separate drive, hot spot tables on separate filegroup (and on separate disk),etc. Check the File Statistics and see if there is higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. Check event log and error log for any errors or warnings related to IO. If you are using SAN (Storage Area Network), check the throughput of the SAN system as well as the configuration of the HBA Queue Depth. In one of my recent projects, the SAN was performing really badly so the SAN administrator did not accept it. After some investigations, he agreed to change the HBA Queue Depth on development (test environment) set up and as soon as we changed the HBA Queue Depth to quite a higher value, there was a sudden big improvement in the performance. It is very possible that there are no proper indexes in the system and there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can effectively reduce lots of CPU, Memory and IO (considering cover index has lesser columns than cluster table and all other; it depends upon the situation). You can refer to the two articles that I wrote; they are about how to optimize indexes: Create Missing Indexes Drop Unused Indexes Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussions of Wait Stats in this blog are generic and vary from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Types, SQL White Papers, T SQL, Technology

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  • Windows 7 - Ubuntu 10.10 Dual Boot Partitioning Recommendation for HP Laptop OEM

    - by Denja
    Hi Linux Community, After been temporary impressed with the newb Windows 7 and after intensly using it I find my self struggling with the ever slow and buggy windows OS once again. It's Time to go with the Ubuntu/Linux way for a better and faster tomorrow. Unfortunately in my country most Users/Business use Windows based Systems. As a Computer technician i want to learn and use both Systems and possibly introduce New users to more affordable Linux Based Systems. For now I want to create dual-boot or even triple boot layouts on my laptop machine Here's the layout in use now: * (C:) Windows 7 system partition NTFS - 284,89GB (Primary,Boot,Pagefile,Dump) * HP_TOOLS system partition FAT32 - 99MB (Primary) * (D:) RECOVERY partition NTFS - 12,90GB (Primary) * SYSTEM partition NTFS 199MB (Primary) Here's the layout I want to make. * (C:) Windows 7 system partition NTFS - 60GB (Primary) (sda1) * (D:) Windows data partition (user files) NTFS - 60GB(Extended or Primary)(sda2);wanna share with Linux * Linux root Ext4 - 10GB (Primary)(sda3) * Linux swap swap- RAM size, 3GB (sda4) * Linux home Ext4- 164,9GB (Extended)(sda5) Question 1: Is the layout that i want to make correct as the Primary and Extended Partition concerns ? Question 2: Can I definitely get rid of SYSTEM Boot loader of windows? Question 3: If I get rid of HP_TOOLS and RECOVERY partition will it be a problem? Question 4: Based on my layout what is your suggestion for a Triple Boot layout for OSX or Puppy Linux? Thank you in advance for your advises and suggestions.

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  • HDD vanished after wakeup from standby

    - by Sam
    In my computer I got two hard drives: One 80GB Intel X25 Postville SSD for the system and a 1,5TB Sata HDD for data. When I put the system into standby, and wake it up again, roundabout 50% of the time the 1,5TB HDD is not found. It just vanished from the system (wreaking havok to all programs running which had open files on it). Even going into the system management and refreshing the drives does not find the lost HDD. There are no messages about this in the event log. After a warm reboot the hdd is found again, just like it should. The system is a Shuttle SP35P2 Pro with 8GB Ram and DualCore CPU, OS is Windows 7 Ultimate. I even set up the OS anew, didn't help. Any ideas what might cause this? How to debug, or maybe even fix it?

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  • You Need BRM When You have EBS – and Even When You Don’t!

    - by bwalstra
    Here is a list of criteria to test your business-systems (Oracle E-Business Suite, EBS) or otherwise to support your lines of digital business - if you score low, you need Oracle Billing and Revenue Management (BRM). Functions Scalability High Availability (99.999%) Performance Extensibility (e.g. APIs, Tools) Upgradability Maintenance Security Standards Compliance Regulatory Compliance (e.g. SOX) User Experience Implementation Complexity Features Customer Management Real-Time Service Authorization Pricing/Promotions Flexibility Subscriptions Usage Rating and Pricing Real-Time Balance Mgmt. Non-Currency Resources Billing & Invoicing A/R & G/L Payments & Collections Revenue Assurance Integration with Key Enterprise Applications Reporting Business Intelligence Order & Service Mgmt (OSM) Siebel CRM E-Business Suite On-/Off-line Mediation Payment Processing Taxation Royalties & Settlements Operations Management Disaster Recovery Overall Evaluation Implementation Configuration Extensibility Maintenance Upgradability Functional Richness Feature Richness Usability OOB Integrations Operations Management Leveraging Oracle Technology Overall Fit for Purpose You need Oracle BRM: Built for high-volume transaction processing Monetizes any service or event based on any metric Supports high-volume usage rating, pricing and promotions Provides real-time charging, service authorization and balance management Supports any account structure (e.g. corporate hierarchies etc.) Scales from low volumes to extremely high volumes of transactions (e.g. billions of trxn per hour) Exposes every single function via APIs (e.g. Java, C/C++, PERL, COM, Web Services, JCA) Immediate Business Benefits of BRM: Improved business agility and performance Supports the flexibility, innovation, and customer-centricity required for current and future business models Faster time to market for new products and services Supports 360 view of the customer in real-time – products can be launched to targeted customers at a record-breaking pace Streamlined deployment and operation Productized integrations, standards-based APIs, and OOB enablement lower deployment and maintenance costs Extensible and scalable solution Minimizes risk – initial phase deployed rapidly; solution extended and scaled seamlessly per business requirements Key Considerations Productized integration with key Oracle applications Lower integration risks and cost Efficient order-to-cash process Engineered solution – certification on Exa platform Exadata tested at PayPal in the re-platforming project Optimal performance of Oracle assets on Oracle hardware Productized solution in Rapid Offer Design and Order Delivery Fast offer design and implementation Significantly shorter order cycle time Productized integration with Oracle Enterprise Manager Visibility to system operability for optimal up time

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  • The type 'XXX' is defined in an assembly that is not referenced exception after upgrade to ASP.NET 4

    - by imran_ku07
       Introduction :          I found two posts in ASP.NET MVC forums complaining that they are getting exception, The type XXX is defined in an assembly that is not referenced, after upgrading thier application into Visual Studio 2010 and .NET Framework 4.0 at here and here .   Description :           The reason why they are getting the above exception is the use of new clean web.config without referencing the assemblies which were presents in ASP.NET 3.5 web.config. The quick solution for this problem is to add the old assemblies in new web.config.          <assemblies>             <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>             <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>             <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>              <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />              <add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, publicKeyToken=b77a5c561934e089" />          </assemblies>    How It works :            Currently i have not tested the above scenario in ASP.NET 4.0 because i have not yet get it. But the above scenario can easily be tested and verified in VS 2008. Just Open the root web.config and remove           <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>             Even you add the reference of System.Core in your project, you will still get the above exception because aspx pages are compiled in separate assembly. You can check this yourself by checking Show Detailed Compiler Output: below in the yellow screen of death, you will find something,/out:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\e907aee4\5fa0acc8\App_Web_y5rd6bdg.dll"             This shows that aspx pages are compiled in separate assembly in Temporary ASP.NET Files.Summary :             After getting the above exception make sure to add the assemblies in web.config or add the Assembly directive at Page level. Hopefully this will helps to solve your problem.       

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  • Screwed Up Again, Did Ya?

    - by rickramsey
    Your turn to wear the Cantaloupe Cap of Shame? Here's how to keep it from happening again: Figure out what data you need to archive Create a solid archive someplace safer than your iphone Get wicked fast at recovering your system. Jesse Butler explains how to do all three for a system running Oracle Solaris 11: How to Recover an Oracle Solaris 11 System Website Newsletter Facebook Twitter

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  • Thread placement policies on NUMA systems - update

    - by Dave
    In a prior blog entry I noted that Solaris used a "maximum dispersal" placement policy to assign nascent threads to their initial processors. The general idea is that threads should be placed as far away from each other as possible in the resource topology in order to reduce resource contention between concurrently running threads. This policy assumes that resource contention -- pipelines, memory channel contention, destructive interference in the shared caches, etc -- will likely outweigh (a) any potential communication benefits we might achieve by packing our threads more densely onto a subset of the NUMA nodes, and (b) benefits of NUMA affinity between memory allocated by one thread and accessed by other threads. We want our threads spread widely over the system and not packed together. Conceptually, when placing a new thread, the kernel picks the least loaded node NUMA node (the node with lowest aggregate load average), and then the least loaded core on that node, etc. Furthermore, the kernel places threads onto resources -- sockets, cores, pipelines, etc -- without regard to the thread's process membership. That is, initial placement is process-agnostic. Keep reading, though. This description is incorrect. On Solaris 10 on a SPARC T5440 with 4 x T2+ NUMA nodes, if the system is otherwise unloaded and we launch a process that creates 20 compute-bound concurrent threads, then typically we'll see a perfect balance with 5 threads on each node. We see similar behavior on an 8-node x86 x4800 system, where each node has 8 cores and each core is 2-way hyperthreaded. So far so good; this behavior seems in agreement with the policy I described in the 1st paragraph. I recently tried the same experiment on a 4-node T4-4 running Solaris 11. Both the T5440 and T4-4 are 4-node systems that expose 256 logical thread contexts. To my surprise, all 20 threads were placed onto just one NUMA node while the other 3 nodes remained completely idle. I checked the usual suspects such as processor sets inadvertently left around by colleagues, processors left offline, and power management policies, but the system was configured normally. I then launched multiple concurrent instances of the process, and, interestingly, all the threads from the 1st process landed on one node, all the threads from the 2nd process landed on another node, and so on. This happened even if I interleaved thread creating between the processes, so I was relatively sure the effect didn't related to thread creation time, but rather that placement was a function of process membership. I this point I consulted the Solaris sources and talked with folks in the Solaris group. The new Solaris 11 behavior is intentional. The kernel is no longer using a simple maximum dispersal policy, and thread placement is process membership-aware. Now, even if other nodes are completely unloaded, the kernel will still try to pack new threads onto the home lgroup (socket) of the primordial thread until the load average of that node reaches 50%, after which it will pick the next least loaded node as the process's new favorite node for placement. On the T4-4 we have 64 logical thread contexts (strands) per socket (lgroup), so if we launch 48 concurrent threads we will find 32 placed on one node and 16 on some other node. If we launch 64 threads we'll find 32 and 32. That means we can end up with our threads clustered on a small subset of the nodes in a way that's quite different that what we've seen on Solaris 10. So we have a policy that allows process-aware packing but reverts to spreading threads onto other nodes if a node becomes too saturated. It turns out this policy was enabled in Solaris 10, but certain bugs suppressed the mixed packing/spreading behavior. There are configuration variables in /etc/system that allow us to dial the affinity between nascent threads and their primordial thread up and down: see lgrp_expand_proc_thresh, specifically. In the OpenSolaris source code the key routine is mpo_update_tunables(). This method reads the /etc/system variables and sets up some global variables that will subsequently be used by the dispatcher, which calls lgrp_choose() in lgrp.c to place nascent threads. Lgrp_expand_proc_thresh controls how loaded an lgroup must be before we'll consider homing a process's threads to another lgroup. Tune this value lower to have it spread your process's threads out more. To recap, the 'new' policy is as follows. Threads from the same process are packed onto a subset of the strands of a socket (50% for T-series). Once that socket reaches the 50% threshold the kernel then picks another preferred socket for that process. Threads from unrelated processes are spread across sockets. More precisely, different processes may have different preferred sockets (lgroups). Beware that I've simplified and elided details for the purposes of explication. The truth is in the code. Remarks: It's worth noting that initial thread placement is just that. If there's a gross imbalance between the load on different nodes then the kernel will migrate threads to achieve a better and more even distribution over the set of available nodes. Once a thread runs and gains some affinity for a node, however, it becomes "stickier" under the assumption that the thread has residual cache residency on that node, and that memory allocated by that thread resides on that node given the default "first-touch" page-level NUMA allocation policy. Exactly how the various policies interact and which have precedence under what circumstances could the topic of a future blog entry. The scheduler is work-conserving. The x4800 mentioned above is an interesting system. Each of the 8 sockets houses an Intel 7500-series processor. Each processor has 3 coherent QPI links and the system is arranged as a glueless 8-socket twisted ladder "mobius" topology. Nodes are either 1 or 2 hops distant over the QPI links. As an aside the mapping of logical CPUIDs to physical resources is rather interesting on Solaris/x4800. On SPARC/Solaris the CPUID layout is strictly geographic, with the highest order bits identifying the socket, the next lower bits identifying the core within that socket, following by the pipeline (if present) and finally the logical thread context ("strand") on the core. But on Solaris on the x4800 the CPUID layout is as follows. [6:6] identifies the hyperthread on a core; bits [5:3] identify the socket, or package in Intel terminology; bits [2:0] identify the core within a socket. Such low-level details should be of interest only if you're binding threads -- a bad idea, the kernel typically handles placement best -- or if you're writing NUMA-aware code that's aware of the ambient placement and makes decisions accordingly. Solaris introduced the so-called critical-threads mechanism, which is expressed by putting a thread into the FX scheduling class at priority 60. The critical-threads mechanism applies to placement on cores, not on sockets, however. That is, it's an intra-socket policy, not an inter-socket policy. Solaris 11 introduces the Power Aware Dispatcher (PAD) which packs threads instead of spreading them out in an attempt to be able to keep sockets or cores at lower power levels. Maximum dispersal may be good for performance but is anathema to power management. PAD is off by default, but power management polices constitute yet another confounding factor with respect to scheduling and dispatching. If your threads communicate heavily -- one thread reads cache lines last written by some other thread -- then the new dense packing policy may improve performance by reducing traffic on the coherent interconnect. On the other hand if your threads in your process communicate rarely, then it's possible the new packing policy might result on contention on shared computing resources. Unfortunately there's no simple litmus test that says whether packing or spreading is optimal in a given situation. The answer varies by system load, application, number of threads, and platform hardware characteristics. Currently we don't have the necessary tools and sensoria to decide at runtime, so we're reduced to an empirical approach where we run trials and try to decide on a placement policy. The situation is quite frustrating. Relatedly, it's often hard to determine just the right level of concurrency to optimize throughput. (Understanding constructive vs destructive interference in the shared caches would be a good start. We could augment the lines with a small tag field indicating which strand last installed or accessed a line. Given that, we could augment the CPU with performance counters for misses where a thread evicts a line it installed vs misses where a thread displaces a line installed by some other thread.)

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  • Cross-language Extension Method Calling

    - by Tom Hines
    Extension methods are a concise way of binding functions to particular types. In my last post, I showed how Extension methods can be created in the .NET 2.0 environment. In this post, I discuss calling the extensions from other languages. Most of the differences I find between the Dot Net languages are mainly syntax.  The declaration of Extensions is no exception.  There is, however, a distinct difference with the framework accepting excensions made with C++ that differs from C# and VB.  When calling the C++ extension from C#, the compiler will SOMETIMES say there is no definition for DoCPP with the error: 'string' does not contain a definition for 'DoCPP' and no extension method 'DoCPP' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?) If I recompile, the error goes away. The strangest problem with calling the C++ extension from C# is that I first must make SOME type of reference to the class BEFORE using the extension or it will not be recognized at all.  So, if I first call the DoCPP() as a static method, the extension works fine later.  If I make a dummy instantiation of the class, it works.  If I have no forward reference of the class, I get the same error as before and recompiling does not fix it.  It seems as if this none of this is supposed to work across the languages. I have made a few work-arounds to get the examples to compile and run. Note the following examples: Extension in C# using System; namespace Extension_CS {    public static class CExtension_CS    {  //in C#, the "this" keyword is the key.       public static void DoCS(this string str)       {          Console.WriteLine("CS\t{0:G}\tCS", str);       }    } } Extension in C++ /****************************************************************************\  * Here is the C++ implementation.  It is the least elegant and most quirky,  * but it works. \****************************************************************************/ #pragma once using namespace System; using namespace System::Runtime::CompilerServices;     //<-Essential // Reference: System.Core.dll //<- Essential namespace Extension_CPP {        public ref class CExtension_CPP        {        public:               [Extension] // or [ExtensionAttribute] /* either works */               static void DoCPP(String^ str)               {                      Console::WriteLine("C++\t{0:G}\tC++", str);               }        }; } Extension in VB ' Here is the VB implementation.  This is not as elegant as the C#, but it's ' functional. Imports System.Runtime.CompilerServices ' Public Module modExtension_VB 'Extension methods can be defined only in modules.    <Extension()> _       Public Sub DoVB(ByVal str As String)       Console.WriteLine("VB" & Chr(9) & "{0:G}" & Chr(9) & "VB", str)    End Sub End Module   Calling program in C# /******************************************************************************\  * Main calling program  * Intellisense and VS2008 complain about the CPP implementation, but with a  * little duct-tape, it works just fine. \******************************************************************************/ using System; using Extension_CPP; using Extension_CS; using Extension_VB; // vitual namespace namespace TestExtensions {    public static class CTestExtensions    {       /**********************************************************************\        * For some reason, this needs a direct reference into the C++ version        * even though it does nothing than add a null reference.        * The constructor provides the fake usage to please the compiler.       \**********************************************************************/       private static CExtension_CPP x = null;   // <-DUCT_TAPE!       static CTestExtensions()       {          // Fake usage to stop compiler from complaining          if (null != x) {} // <-DUCT_TAPE       }       static void Main(string[] args)       {          string strData = "from C#";          strData.DoCPP();          strData.DoCS();          strData.DoVB();       }    } }   Calling program in VB  Imports Extension_CPP Imports Extension_CS Imports Extension_VB Imports System.Runtime.CompilerServices Module TestExtensions_VB    <Extension()> _       Public Sub DoCPP(ByVal str As String)       'Framework does not treat this as an extension, so use the static       CExtension_CPP.DoCPP(str)    End Sub    Sub Main()       Dim strData As String = "from VB"       strData.DoCS()       strData.DoVB()       strData.DoCPP() 'fake    End Sub End Module  Calling program in C++ // TestExtensions_CPP.cpp : main project file. #include "stdafx.h" using namespace System; using namespace Extension_CPP; using namespace Extension_CS; using namespace Extension_VB; void main(void) {        /*******************************************************\         * Extension methods are called like static methods         * when called from C++.  There may be a difference in         * syntax when calling the VB extension as VB Extensions         * are embedded in Modules instead of classes        \*******************************************************/     String^ strData = "from C++";     CExtension_CPP::DoCPP(strData);     CExtension_CS::DoCS(strData);     modExtension_VB::DoVB(strData); //since Extensions go in Modules }

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  • Announcing Unbreakable Enterprise Kernel Release 3 for Oracle Linux

    - by Lenz Grimmer
    We are excited to announce the general availability of the Unbreakable Enterprise Kernel Release 3 for Oracle Linux 6. The Unbreakable Enterprise Kernel Release 3 (UEK R3) is Oracle's third major supported release of its heavily tested and optimized Linux kernel for Oracle Linux 6 on the x86_64 architecture. UEK R3 is based on mainline Linux version 3.8.13. Some notable highlights of this release include: Inclusion of DTrace for Linux into the kernel (no longer a separate kernel image). DTrace for Linux now supports probes for user-space statically defined tracing (USDT) in programs that have been modified to include embedded static probe points Production support for Linux containers (LXC) which were previously released as a technology preview Btrfs file system improvements (subvolume-aware quota groups, cross-subvolume reflinks, btrfs send/receive to transfer file system snapshots or incremental differences, file hole punching, hot-replacing of failed disk devices, device statistics) Improved support for Control Groups (cgroups)  The ext4 file system can now store the content of a small file inside the inode (inline_data) TCP fast open (TFO) can speed up the opening of successive TCP connections between two endpoints FUSE file system performance improvements on NUMA systems Support for the Intel Ivy Bridge (IVB) processor family Integration of the OpenFabrics Enterprise Distribution (OFED) 2.0 stack, supporting a wide range of Infinband protocols including updates to Oracle's Reliable Datagram Sockets (RDS) Numerous driver updates in close coordination with our hardware partners UEK R3 uses the same versioning model as the mainline Linux kernel version. Unlike in UEK R2 (which identifies itself as version "2.6.39", even though it is based on mainline Linux 3.0.x), "uname" returns the actual version number (3.8.13). For further details on the new features, changes and any known issues, please consult the Release Notes. The Unbreakable Enterprise Kernel Release 3 and related packages can be installed using the yum package management tool on Oracle Linux 6 Update 4 or newer, both from the Unbreakable Linux Network (ULN) and our public yum server. Please follow the installation instructions in the Release Notes for a detailed description of the steps involved. The kernel source tree will also available via the git source code revision control system from https://oss.oracle.com/git/?p=linux-uek3-3.8.git If you would like to discuss your experiences with Oracle Linux and UEK R3, we look forward to your feedback on our public Oracle Linux Forum.

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  • Failed to get i915 symbols, graphics turbo disabled

    - by Optimus Prime
    I'm getting "Failed to get i915 symbols, graphics turbo disabled" error message after installing following softwares and few updates from Ubuntu. Django, Mysql server 5.5 Mysql benchmark And i have installed few updates for ubuntu. It was showing as Security Updates for Ubuntu. After installing Updates the update manager showed that i should restart the system. On restart i got following error message. " failed to get i915 symbols, graphics turbo disabled". So i tried the work around mentioned here (using the Live CD) ie add intel_ips to the blacklist echo "blacklist intel_ips" /etc/modprobe.d/blacklist.conf add i915 and intel_ips to /etc/modules echo -e "i915/nintel_ips" /etc/modules Now when start the system it freezes at Ubuntu splash screen. I'm using Ubuntu 12.04 LTS, on Dell inspiron N1040. I need to boot the system as i have spend lot of days configuring. Python and Django. Please help EDIT : OK when i restarted the system yesterday it magically turned on. Now i can view my desktop. But one problem, i can't mount any of the drives. It says failed to mount Drive. I'm also frequently getting "Ubuntu System Failure" Error Message.

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  • Improper output in SSH session on OSX using FreeSSHd on Windows with cygwin bash/sh shell

    - by Tyler Clendenin
    I am testing out running an SSH server on a local Windows VM. I have installed FreeSSHd and set the command shell to "c:\cygwin\bin\sh --login -i" (bash as well) with "Use new console engine" unchecked. (When it was enabled no output would show through the ssh connection anyway) The shell seems to work, but when connecting from my OS-X terminal using ssh all of the shell results comes out ill formatted. $ ls -al total 17 drwxr-xr-x+ 1 SYSTEM Administrators 4096 Feb 2 01:00 . drwxrwxrwt+ 1 Administrator Administrators 0 Feb 2 01:01 .. -rw------- 1 SYSTEM Administrators 128 Feb 2 01:30 .bash_history -rwxr-xr-x 1 SYSTEM Administrators 1150 Feb 2 00:55 .bash_profile -rwxr-xr-x 1 SYSTEM Administrators 3754 Feb 2 00:55 .bashrc -rwxr-xr-x 1 SYSTEM Administrators 1461 Feb 2 00:55 .inputrc Any ideas on why this is happening, how I can fix this?

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  • Sony VAIO with Insyde H2O EFI bios will not boot into GRUB EFI

    - by Rohan Dhruva
    I bought a new Sony Vaio S series laptop. It uses Insyde H2O BIOS EFI, and trying to install Linux on it is driving me crazy. root@kubuntu:~# parted /dev/sda print Model: ATA Hitachi HTS72756 (scsi) Disk /dev/sda: 640GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 274MB 273MB fat32 EFI system partition hidden 2 274MB 20.8GB 20.6GB ntfs Basic data partition hidden, diag 3 20.8GB 21.1GB 273MB fat32 EFI system partition boot 4 21.1GB 21.3GB 134MB Microsoft reserved partition msftres 5 21.3GB 342GB 320GB ntfs Basic data partition 6 342GB 358GB 16.1GB ext4 Basic data partition 7 358GB 374GB 16.1GB ntfs Basic data partition 8 374GB 640GB 266GB ntfs Basic data partition What is surprising is that there are 2 EFI system partitions on the disk. The sda2 partition is a 20gb recovery partition which loads windows with a basic recovery interface. This is accessible by pressing the "ASSIST" button as opposed to the normal power button. I presume that the sda1 EFI System Partition (ESP) loads into this recovery. The sda3 ESP has more fleshed out entries for Microsoft Windows, which actually goes into Windows 7 (as confirmed by bcdedit.exe on Windows). Ubuntu is installed on sda6, and while installation I chose sda3 as my boot partition. The installer correctly created a sda3/EFI/ubuntu/grubx64.efi application. The real problem: for the life of me, I can't set it to be the default! I tried creating a sda3/startup.nsh which called grubx64.efi, but it didn't help -- on rebooting, the system still boots into windows. I tried using efibootmgr, and that shows as it it worked: root@kubuntu:~# efibootmgr BootCurrent: 0000 BootOrder: 0000,0001 Boot0000* EFI USB Device Boot0001* Windows Boot Manager root@kubuntu:~# efibootmgr --create --gpt --disk /dev/sda --part 3 --write-signature --label "GRUB2" --loader "\\EFI\\ubuntu\\grubx64.efi" BootCurrent: 0000 BootOrder: 0002,0000,0001 Boot0000* EFI USB Device Boot0001* Windows Boot Manager Boot0002* GRUB2 root@kubuntu:~# efibootmgr BootCurrent: 0000 BootOrder: 0002,0000,0001 Boot0000* EFI USB Device Boot0001* Windows Boot Manager Boot0002* GRUB2 However, on rebooting, as you guessed, the machine rebooted directly back into Windows. The only things I can think of are: The sda1 partition is somehow being used Overwrite /EFI/Boot/bootx64.efi and /EFI/Microsoft/Boot/bootmgfw.efi with grubx64.efi [but this seems really radical]. Can anyone please help me out? Thanks -- any help is greatly appreciated, as this issue is driving me crazy!

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  • 10 Windows Tweaking Myths Debunked

    - by Chris Hoffman
    Windows is big, complicated, and misunderstood. You’ll still stumble across bad advice from time to time when browsing the web. These Windows tweaking, performance, and system maintenance tips are mostly just useless, but some are actively harmful. Luckily, most of these myths have been stomped out on mainstream sites and forums. However, if you start searching the web, you’ll still find websites that recommend you do these things. Erase Cache Files Regularly to Speed Things Up You can free up disk space by running an application like CCleaner, another temporary-file-cleaning utility, or even the Windows Disk Cleanup tool. In some cases, you may even see an old computer speed up when you erase a large amount of useless files. However, running CCleaner or similar utilities every day to erase your browser’s cache won’t actually speed things up. It will slow down your web browsing as your web browser is forced to redownload the files all over again, and reconstruct the cache you regularly delete. If you’ve installed CCleaner or a similar program and run it every day with the default settings, you’re actually slowing down your web browsing. Consider at least preventing the program from wiping out your web browser cache. Enable ReadyBoost to Speed Up Modern PCs Windows still prompts you to enable ReadyBoost when you insert a USB stick or memory card. On modern computers, this is completely pointless — ReadyBoost won’t actually speed up your computer if you have at least 1 GB of RAM. If you have a very old computer with a tiny amount of RAM — think 512 MB — ReadyBoost may help a bit. Otherwise, don’t bother. Open the Disk Defragmenter and Manually Defragment On Windows 98, users had to manually open the defragmentation tool and run it, ensuring no other applications were using the hard drive while it did its work. Modern versions of Windows are capable of defragmenting your file system while other programs are using it, and they automatically defragment your disks for you. If you’re still opening the Disk Defragmenter every week and clicking the Defragment button, you don’t need to do this — Windows is doing it for you unless you’ve told it not to run on a schedule. Modern computers with solid-state drives don’t have to be defragmented at all. Disable Your Pagefile to Increase Performance When Windows runs out of empty space in RAM, it swaps out data from memory to a pagefile on your hard disk. If a computer doesn’t have much memory and it’s running slow, it’s probably moving data to the pagefile or reading data from it. Some Windows geeks seem to think that the pagefile is bad for system performance and disable it completely. The argument seems to be that Windows can’t be trusted to manage a pagefile and won’t use it intelligently, so the pagefile needs to be removed. As long as you have enough RAM, it’s true that you can get by without a pagefile. However, if you do have enough RAM, Windows will only use the pagefile rarely anyway. Tests have found that disabling the pagefile offers no performance benefit. Enable CPU Cores in MSConfig Some websites claim that Windows may not be using all of your CPU cores or that you can speed up your boot time by increasing the amount of cores used during boot. They direct you to the MSConfig application, where you can indeed select an option that appears to increase the amount of cores used. In reality, Windows always uses the maximum amount of processor cores your CPU has. (Technically, only one core is used at the beginning of the boot process, but the additional cores are quickly activated.) Leave this option unchecked. It’s just a debugging option that allows you to set a maximum number of cores, so it would be useful if you wanted to force Windows to only use a single core on a multi-core system — but all it can do is restrict the amount of cores used. Clean Your Prefetch To Increase Startup Speed Windows watches the programs you run and creates .pf files in its Prefetch folder for them. The Prefetch feature works as a sort of cache — when you open an application, Windows checks the Prefetch folder, looks at the application’s .pf file (if it exists), and uses that as a guide to start preloading data that the application will use. This helps your applications start faster. Some Windows geeks have misunderstood this feature. They believe that Windows loads these files at boot, so your boot time will slow down due to Windows preloading the data specified in the .pf files. They also argue you’ll build up useless files as you uninstall programs and .pf files will be left over. In reality, Windows only loads the data in these .pf files when you launch the associated application and only stores .pf files for the 128 most recently launched programs. If you were to regularly clean out the Prefetch folder, not only would programs take longer to open because they won’t be preloaded, Windows will have to waste time recreating all the .pf files. You could also modify the PrefetchParameters setting to disable Prefetch, but there’s no reason to do that. Let Windows manage Prefetch on its own. Disable QoS To Increase Network Bandwidth Quality of Service (QoS) is a feature that allows your computer to prioritize its traffic. For example, a time-critical application like Skype could choose to use QoS and prioritize its traffic over a file-downloading program so your voice conversation would work smoothly, even while you were downloading files. Some people incorrectly believe that QoS always reserves a certain amount of bandwidth and this bandwidth is unused until you disable it. This is untrue. In reality, 100% of bandwidth is normally available to all applications unless a program chooses to use QoS. Even if a program does choose to use QoS, the reserved space will be available to other programs unless the program is actively using it. No bandwidth is ever set aside and left empty. Set DisablePagingExecutive to Make Windows Faster The DisablePagingExecutive registry setting is set to 0 by default, which allows drivers and system code to be paged to the disk. When set to 1, drivers and system code will be forced to stay resident in memory. Once again, some people believe that Windows isn’t smart enough to manage the pagefile on its own and believe that changing this option will force Windows to keep important files in memory rather than stupidly paging them out. If you have more than enough memory, changing this won’t really do anything. If you have little memory, changing this setting may force Windows to push programs you’re using to the page file rather than push unused system files there — this would slow things down. This is an option that may be helpful for debugging in some situations, not a setting to change for more performance. Process Idle Tasks to Free Memory Windows does things, such as creating scheduled system restore points, when you step away from your computer. It waits until your computer is “idle” so it won’t slow your computer and waste your time while you’re using it. Running the “Rundll32.exe advapi32.dll,ProcessIdleTasks” command forces Windows to perform all of these tasks while you’re using the computer. This is completely pointless and won’t help free memory or anything like that — all you’re doing is forcing Windows to slow your computer down while you’re using it. This command only exists so benchmarking programs can force idle tasks to run before performing benchmarks, ensuring idle tasks don’t start running and interfere with the benchmark. Delay or Disable Windows Services There’s no real reason to disable Windows services anymore. There was a time when Windows was particularly heavy and computers had little memory — think Windows Vista and those “Vista Capable” PCs Microsoft was sued over. Modern versions of Windows like Windows 7 and 8 are lighter than Windows Vista and computers have more than enough memory, so you won’t see any improvements from disabling system services included with Windows. Some people argue for not disabling services, however — they recommend setting services from “Automatic” to “Automatic (Delayed Start)”. By default, the Delayed Start option just starts services two minutes after the last “Automatic” service starts. Setting services to Delayed Start won’t really speed up your boot time, as the services will still need to start — in fact, it may lengthen the time it takes to get a usable desktop as services will still be loading two minutes after booting. Most services can load in parallel, and loading the services as early as possible will result in a better experience. The “Delayed Start” feature is primarily useful for system administrators who need to ensure a specific service starts later than another service. If you ever find a guide that recommends you set a little-known registry setting to improve performance, take a closer look — the change is probably useless. Want to actually speed up your PC? Try disabling useless startup programs that run on boot, increasing your boot time and consuming memory in the background. This is a much better tip than doing any of the above, especially considering most Windows PCs come packed to the brim with bloatware.     

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  • C # - a variable using the Encrypt md5

    - by Guilherme Cardoso
    When we are dealing with more sensitive data and important as a keyword, it is not appropriate at all stores them in database without encrypting for security reasons.  For this we use MD5  MD5 is an algorithm that allow us to encript an string, but doesn't leave us desencrypt it (not sure if it is already possible, but at least I know there are many databases already having a record).  The method below will return us a variable encrypted with md5. For example: md5_encriptar (pontonetpt.com ");   The result will be: 34efe85d338075834ad41803eb08c0df This way we save tthese encrypted data into a database, and then to make comparisons we often use the method to compare with the records kept. public string md5_encrypt(string md5) { System.Security.Cryptography.MD5CryptoServiceProvider x = new System.Security.Cryptography.MD5CryptoServiceProvider(); byte[] bs = System.Text.Encoding.UTF8.GetBytes(md5); bs = x.ComputeHash(bs); System.Text.StringBuilder s = new System.Text.StringBuilder(); foreach (byte b in bs) { s.Append(b.ToString("x2").ToLower()); } string password = s.ToString(); return password; }

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  • Fastest pathfinding for static node matrix

    - by Sean Martin
    I'm programming a route finding routine in VB.NET for an online game I play, and I'm searching for the fastest route finding algorithm for my map type. The game takes place in space, with thousands of solar systems connected by jump gates. The game devs have provided a DB dump containing a list of every system and the systems it can jump to. The map isn't quite a node tree, since some branches can jump to other branches - more of a matrix. What I need is a fast pathfinding algorithm. I have already implemented an A* routine and a Dijkstra's, both find the best path but are too slow for my purposes - a search that considers about 5000 nodes takes over 20 seconds to compute. A similar program on a website can do the same search in less than a second. This website claims to use D*, which I have looked into. That algorithm seems more appropriate for dynamic maps rather than one that does not change - unless I misunderstand it's premise. So is there something faster I can use for a map that is not your typical tile/polygon base? GBFS? Perhaps a DFS? Or have I likely got some problem with my A* - maybe poorly chosen heuristics or movement cost? Currently my movement cost is the length of the jump (the DB dump has solar system coordinates as well), and the heuristic is a quick euclidean calculation from the node to the goal. In case anyone has some optimizations for my A*, here is the routine that consumes about 60% of my processing time, according to my profiler. The coordinateData table contains a list of every system's coordinates, and neighborNode.distance is the distance of the jump. Private Function findDistance(ByVal startSystem As Integer, ByVal endSystem As Integer) As Integer 'hCount += 1 'If hCount Mod 0 = 0 Then 'Return hCache 'End If 'Initialize variables to be filled Dim x1, x2, y1, y2, z1, z2 As Integer 'LINQ queries for solar system data Dim systemFromData = From result In jumpDataDB.coordinateDatas Where result.systemId = startSystem Select result.x, result.y, result.z Dim systemToData = From result In jumpDataDB.coordinateDatas Where result.systemId = endSystem Select result.x, result.y, result.z 'LINQ execute 'Fill variables with solar system data for from and to system For Each solarSystem In systemFromData x1 = (solarSystem.x) y1 = (solarSystem.y) z1 = (solarSystem.z) Next For Each solarSystem In systemToData x2 = (solarSystem.x) y2 = (solarSystem.y) z2 = (solarSystem.z) Next Dim x3 = Math.Abs(x1 - x2) Dim y3 = Math.Abs(y1 - y2) Dim z3 = Math.Abs(z1 - z2) 'Calculate distance and round 'Dim distance = Math.Round(Math.Sqrt(Math.Abs((x1 - x2) ^ 2) + Math.Abs((y1 - y2) ^ 2) + Math.Abs((z1 - z2) ^ 2))) Dim distance = firstConstant * Math.Min(secondConstant * (x3 + y3 + z3), Math.Max(x3, Math.Max(y3, z3))) 'Dim distance = Math.Abs(x1 - x2) + Math.Abs(z1 - z2) + Math.Abs(y1 - y2) 'hCache = distance Return distance End Function And the main loop, the other 30% 'Begin search While openList.Count() != 0 'Set current system and move node to closed currentNode = lowestF() move(currentNode.id) For Each neighborNode In neighborNodes If Not onList(neighborNode.toSystem, 0) Then If Not onList(neighborNode.toSystem, 1) Then Dim newNode As New nodeData() newNode.id = neighborNode.toSystem newNode.parent = currentNode.id newNode.g = currentNode.g + neighborNode.distance newNode.h = findDistance(newNode.id, endSystem) newNode.f = newNode.g + newNode.h newNode.security = neighborNode.security openList.Add(newNode) shortOpenList(OLindex) = newNode.id OLindex += 1 Else Dim proposedG As Integer = currentNode.g + neighborNode.distance If proposedG < gValue(neighborNode.toSystem) Then changeParent(neighborNode.toSystem, currentNode.id, proposedG) End If End If End If Next 'Check to see if done If currentNode.id = endSystem Then Exit While End If End While If clarification is needed on my spaghetti code, I'll try to explain.

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  • Service Broker, not ETL

    - by jamiet
    I have been very quiet on this blog of late and one reason for that is I have been very busy on a client project that I would like to talk about a little here. The client that I have been working for has a website that runs on a distributed architecture utilising a messaging infrastructure for communication between different endpoints. My brief was to build a system that could consume these messages and produce analytical information in near-real-time. More specifically I basically had to deliver a data warehouse however it was the real-time aspect of the project that really intrigued me. This real-time requirement meant that using an Extract transformation, Load (ETL) tool was out of the question and so I had no choice but to write T-SQL code (i.e. stored-procedures) to process the incoming messages and load the data into the data warehouse. This concerned me though – I had no way to control the rate at which data would arrive into the system yet we were going to have end-users querying the system at the same time that those messages were arriving; the potential for contention in such a scenario was pretty high and and was something I wanted to minimise as much as possible. Moreover I did not want the processing of data inside the data warehouse to have any impact on the customer-facing website. As you have probably guessed from the title of this blog post this is where Service Broker stepped in! For those that have not heard of it Service Broker is a queuing technology that has been built into SQL Server since SQL Server 2005. It provides a number of features however the one that was of interest to me was the fact that it facilitates asynchronous data processing which, in layman’s terms, means the ability to process some data without requiring the system that supplied the data having to wait for the response. That was a crucial feature because on this project the customer-facing website (in effect an OLTP system) would be calling one of our stored procedures with each message – we did not want to cause the OLTP system to wait on us every time we processed one of those messages. This asynchronous nature also helps to alleviate the contention problem because the asynchronous processing activity is handled just like any other task in the database engine and hence can wait on another task (such as an end-user query). Service Broker it was then! The stored procedure called by the OLTP system would simply put the message onto a queue and we would use a feature called activation to pick each message off the queue in turn and process it into the warehouse. At the time of writing the system is not yet up to full capacity but so far everything seems to be working OK (touch wood) and crucially our users are seeing data in near-real-time. By near-real-time I am talking about latencies of a few minutes at most and to someone like me who is used to building systems that have overnight latencies that is a huge step forward! So then, am I advocating that you all go out and dump your ETL tools? Of course not, no! What this project has taught me though is that in certain scenarios there may be better ways to implement a data warehouse system then the traditional “load data in overnight” approach that we are all used to. Moreover I have really enjoyed getting to grips with a new technology and even if you don’t want to use Service Broker you might want to consider asynchronous messaging architectures for your BI/data warehousing solutions in the future. This has been a very high level overview of my use of Service Broker and I have deliberately left out much of the minutiae of what has been a very challenging implementation. Nonetheless I hope I have caused you to reflect upon your own approaches to BI and question whether other approaches may be more tenable. All comments and questions gratefully received! Lastly, if you have never used Service Broker before and want to kick the tyres I have provided below a very simple “Service Broker Hello World” script that will create all of the objects required to facilitate Service Broker communications and then send the message “Hello World” from one place to anther! This doesn’t represent a “proper” implementation per se because it doesn’t close down down conversation objects (which you should always do in a real-world scenario) but its enough to demonstrate the capabilities! @Jamiet ----------------------------------------------------------------------------------------------- /*This is a basic Service Broker Hello World app. Have fun! -Jamie */ USE MASTER GO CREATE DATABASE SBTest GO --Turn Service Broker on! ALTER DATABASE SBTest SET ENABLE_BROKER GO USE SBTest GO -- 1) we need to create a message type. Note that our message type is -- very simple and allowed any type of content CREATE MESSAGE TYPE HelloMessage VALIDATION = NONE GO -- 2) Once the message type has been created, we need to create a contract -- that specifies who can send what types of messages CREATE CONTRACT HelloContract (HelloMessage SENT BY INITIATOR) GO --We can query the metadata of the objects we just created SELECT * FROM   sys.service_message_types WHERE name = 'HelloMessage'; SELECT * FROM   sys.service_contracts WHERE name = 'HelloContract'; SELECT * FROM   sys.service_contract_message_usages WHERE  service_contract_id IN (SELECT service_contract_id FROM sys.service_contracts WHERE name = 'HelloContract') AND        message_type_id IN (SELECT message_type_id FROM sys.service_message_types WHERE name = 'HelloMessage'); -- 3) The communication is between two endpoints. Thus, we need two queues to -- hold messages CREATE QUEUE SenderQueue CREATE QUEUE ReceiverQueue GO --more querying metatda SELECT * FROM sys.service_queues WHERE name IN ('SenderQueue','ReceiverQueue'); --we can also select from the queues as if they were tables SELECT * FROM SenderQueue   SELECT * FROM ReceiverQueue   -- 4) Create the required services and bind them to be above created queues CREATE SERVICE Sender   ON QUEUE SenderQueue CREATE SERVICE Receiver   ON QUEUE ReceiverQueue (HelloContract) GO --more querying metadata SELECT * FROM sys.services WHERE name IN ('Receiver','Sender'); -- 5) At this point, we can begin the conversation between the two services by -- sending messages DECLARE @conversationHandle UNIQUEIDENTIFIER DECLARE @message NVARCHAR(100) BEGIN   BEGIN TRANSACTION;   BEGIN DIALOG @conversationHandle         FROM SERVICE Sender         TO SERVICE 'Receiver'         ON CONTRACT HelloContract WITH ENCRYPTION=OFF   -- Send a message on the conversation   SET @message = N'Hello, World';   SEND  ON CONVERSATION @conversationHandle         MESSAGE TYPE HelloMessage (@message)   COMMIT TRANSACTION END GO --check contents of queues SELECT * FROM SenderQueue   SELECT * FROM ReceiverQueue   GO -- Receive a message from the queue RECEIVE CONVERT(NVARCHAR(MAX), message_body) AS MESSAGE FROM ReceiverQueue GO --If no messages were received and/or you can't see anything on the queues you may wish to check the following for clues: SELECT * FROM sys.transmission_queue -- Cleanup DROP SERVICE Sender DROP SERVICE Receiver DROP QUEUE SenderQueue DROP QUEUE ReceiverQueue DROP CONTRACT HelloContract DROP MESSAGE TYPE HelloMessage GO USE MASTER GO DROP DATABASE SBTest GO

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  • Ubuntu on Android for Samsung Galaxy note 2?

    - by schulzey
    This question is lengthy, I have to warn you. I'm generally a mac user. My setup currently consists of using mac osx and vmware (windows 7) to run one program that isn't compatible with osx or linux. This program can be run using crossover (wine) as well but it works better with vmware. I'm thinking of switching over to ubuntu as my main operating system on my computers and running vmware or crossover that way to access the program I need. No specific reason why, I guess I'm just sick of the apple/windows machine. I've always wanted to try linux so figure there is no better time than now. The point is I haven't used ubuntu yet so I don't know a lot about it. I was planning on buying the iphone 5 when I saw there is an app to setup ubuntu operating system on an android phone. I'm now thinking that this would be fantastic for me if I bought the samsung galaxy note 2 and was able to install ubuntu and either vmware or crossover to use my windows specific program for work right on my phone. The samsung galaxy note 2 has a 1.4 ghz processor and 2gb of ram which is enough to handle a modern operating system. My program does not need a lot of speed or memory to work. To be honest, the windows specific program I need would work fine on an old laptop running windows xp. My first question is if ubuntu for android is really the full operating system that lets you run programs just like a desktop pc? Is it super slow where it takes many minutes to load up ubuntu? I don't need blazing speeds, but I'd like something useable. My next question has to do with vmware or crossover. Is ubuntu for android capable of running these programs? I think it would be great to use the same operating system like ubuntu on my desktop, laptop, tablets, and phone. Thanks so much for all the help!!!

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  • Partial upgrade error

    - by Dan
    this is an issue I have googled a lot and I have tried a lot of fixes, but non of them really worked. At some point (I can't remember when/how) my Update system sort of broke, and since then it is always complaining about "Not all updates can be installed, run a Partial Upgrade". If I click on Partial Upgrade, I get the following result But running apt-get install -f does not fix anything, and at the end I always get the following message Funny thing is that my apt-get system works perfect on Console. I can update my system through apt-get update, apt-get upgrade etc.. So.. how can I fix the graphic interface? I understand that my apt-get system is not broken, but somehow its GUI it is. Any thoughts about it? THANKS! P.D: I have already tried sudo dpkg --configure -a and sudo apt-get autoremove

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  • Tip #13 java.io.File Surprises

    - by ByronNevins
    There is an assumption that I've seen in code many times that is totally wrong.  And this assumption can easily bite you.  The assumption is: File.getAbsolutePath and getAbsoluteFile return paths that are not relative.  Not true!  Sort of.  At least not in the way many people would assume.  All they do is make sure that the beginning of the path is absolute.  The rest of the path can be loaded with relative path elements.  What do you think the following code will print? public class Main {    public static void main(String[] args) {        try {            File f = new File("/temp/../temp/../temp/../");            File abs  = f.getAbsoluteFile();            File parent = abs.getParentFile();            System.out.println("Exists: " + f.exists());            System.out.println("Absolute Path: " + abs);            System.out.println("FileName: " + abs.getName());            System.out.printf("The Parent Directory of %s is %s\n", abs, parent);            System.out.printf("The CANONICAL Parent Directory of CANONICAL %s is %s\n",                        abs, abs.getCanonicalFile().getParent());            System.out.printf("The CANONICAL Parent Directory of ABSOLUTE %s is %s\n",                        abs, parent.getCanonicalFile());            System.out.println("Canonical Path: " + f.getCanonicalPath());        }        catch (IOException ex) {            System.out.println("Got an exception: " + ex);        }    }} Output: Exists: trueAbsolute Path: D:\temp\..\temp\..\temp\..FileName: ..The Parent Directory of D:\temp\..\temp\..\temp\.. is D:\temp\..\temp\..\tempThe CANONICAL Parent Directory of CANONICAL D:\temp\..\temp\..\temp\.. is nullThe CANONICAL Parent Directory of ABSOLUTE D:\temp\..\temp\..\temp\.. is D:\tempCanonical Path: D:\ Notice how it says that the parent of d:\ is d:\temp !!!The file, f, is really the root directory.  The parent is supposed to be null. I learned about this the hard way! getParentXXX simply hacks off the final item in the path. You can get totally unexpected results like the above. Easily. I filed a bug on this behavior a few years ago[1].   Recommendations: (1) Use getCanonical instead of getAbsolute.  There is a 1:1 mapping of files and canonical filenames.  I.e each file has one and only one canonical filename and it will definitely not have relative path elements in it.  There are an infinite number of absolute paths for each file. (2) To get the parent file for File f do the following instead of getParentFile: File parent = new File(f, ".."); [1] http://bt2ws.central.sun.com/CrPrint?id=6687287

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  • Difference in VISUAL STUDIO VERSIONS

    - by karthik ram
    I would like to understand some fundamental VS version differences, What is the difference between Visual Studio 2008 and Visual Studio 2008 Team System? Does the Team System 2008 include VS2008, TFS 2008 & Team Explorer 2008? Furthermore, what is the difference betwene Team System 2008 and Team Suite 2008? I beleive there are no more Team Suites or Team Systems in 2010? Does Visual Studio Ultimate 2010 include all Team System components, like TFS 2010 & Team Explorer 2010, so in effect it is like an upgrade of Visual Studio 2008 Team System? Or does TFS 2010 & Team Explorer 2010 need to be installed separately?

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  • HDD is not readable - can I fix this

    - by user1983017
    I have two HDD in my system, but today morning the additional hard disk is not readable. My all data are kept inside the additional HDD. When I disconnect the additional HDD from my system then system boot as usual, but when I connect HDD my system hangs Up in windows boot logo. Please note this problem is not related to HDD order. When I connect only the additional HDD then system shows this error: disk not readable press ctrl+alt+del to restart I can see the name of additional HDD in BIOS. When I connect both HDD i get a continues beep... beeep .. beep sound. Please tell me is my HDD gone dead ? How do I get the data back ? is there any kit for recovering HDD data ?

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  • Mysterious winamp ratings that come from nowhere

    - by Phenom
    Winamp gives the option to rate songs. This is not a new feature. Everytime I would reinstall Windows and reinstall Winamp my ratings would all go away as expected, and I would have to re-rate everything. However, this time when I reinstalled Winamp, after using it for a few days, songs would appear in my top rated list as being rated. Some of these I remember rating a long time ago before I reinstalled Windows, and some of these I don't remember ever rating. Where are these ratings coming from?

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  • How do you limit root partition disk access to allow drive to go into stanby mode?

    - by Casey
    When there are no users on my system, I would like the hard disk to spindown to low-power state. I realize that this might not be 100% achievable for a straight 24 hours, but it seems reasonable that the system could remain idle for a few hours at a time when it is not in use. My system is headless and running a limited number of services. The primary services are: exim4, mythtv-backend, nfs, samba, cups, apt-cacher-ng Assume that drives are already enabled to go into standby mode. Also, its not acceptable to increase the write-back timeout, since my system is not on a UPS.

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  • How to get rid of devices in the right panel of Nautilus ?

    - by Patryk
    I would like to rid of not mounted ntfs partition from Nautilus' right panel ( I just want 352 GB Filesystem - d drive to be there. First of all 352 GB Filesystem is in fact d so I do not know why it is duplicated. Secondly I have put Acer and SYSTEM RESERVED to be nouser mounts on purpose, so that I (or sombody else) will not format it (or else) by accident. So my /etc/fstab looks like this : #comments....... # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 UUID=1384cee0-6a71-4b83-b0d3-1338db925168 / ext4 noatime,errors=remount-ro 0 1 UUID=e3729117-b936-4c1d-9883-aee73dab6729 none swap sw 0 0 #------ MY WINDOWS D DRIVE---------- UUID=98E8B14DE8B12A80 /media/d ntfs defaults,errors=remount-ro,user 0 0 # #-------ACER---------------- UUID=01CBEA9D4476C2F0 /media/acer ntfs defaults,noauto,noexec,ro,nouser 0 0 # #-------SYSTEM RESERVED----- UUID=01CBEA95760F9330 /media/systemreserved ntfs defaults,noauto,noexec,ro,nouser 0 0 #UUID=58F9-C17E /boot/efi vfat defaults 0 1 blkid and fdisk -l root@XXX:/home/YYY# fdisk -l ... Device Boot Start End Blocks Id System /dev/sda1 4096 27262975 13629440 27 Hidden NTFS WinRE /dev/sda2 27262992 27467791 102400 7 HPFS/NTFS/exFAT /dev/sda3 27467792 232267775 102399992 7 HPFS/NTFS/exFAT /dev/sda4 232267793 976771071 372251639+ f W95 Ext'd (LBA) /dev/sda5 232267795 918867967 343300086+ 7 HPFS/NTFS/exFAT /dev/sda6 * 918870016 968044543 24587264 83 Linux /dev/sda7 968046592 976771071 4362240 82 Linux swap / Solaris root@XXX:/home/YYY# blkid /dev/sda1: LABEL="PQSERVICE" UUID="01CBEA95730D28A0" TYPE="ntfs" /dev/sda2: LABEL="SYSTEM RESERVED" UUID="01CBEA95760F9330" TYPE="ntfs" /dev/sda3: LABEL="Acer" UUID="01CBEA9D4476C2F0" TYPE="ntfs" /dev/sda5: UUID="98E8B14DE8B12A80" TYPE="ntfs" /dev/sda6: UUID="1384cee0-6a71-4b83-b0d3-1338db925168" TYPE="ext4" /dev/sda7: UUID="e3729117-b936-4c1d-9883-aee73dab6729" TYPE="swap"

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