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  • centos 6 ps aux hangs up

    - by Guntis
    I have problem with my server. Server is running centos 6 (CloudLinux Server release 6.2). uname -a = 2.6.32-320.4.1.lve1.1.4.el6.x86_64 That is a kvm guest. On host is debian 6. If i run command ps aux, it stuck on random process (shows some processes only), top command is working fine. htop doesn't work too (black screen). top - 12:11:51 up 34 min, 1 user, load average: 4.26, 6.71, 16.15 Tasks: 201 total, 7 running, 192 sleeping, 0 stopped, 2 zombie Cpu(s): 7.9%us, 2.8%sy, 0.0%ni, 87.5%id, 1.6%wa, 0.0%hi, 0.2%si, 0.0%st Mem: 9862044k total, 2359484k used, 7502560k free, 171720k buffers Swap: 10485720k total, 0k used, 10485720k free, 1336872k cached server has one Intel(R) Xeon(R) CPU E5606 @ 2.13GHz, free -m total used free shared buffers cached Mem: 9630 2336 7293 0 170 1324 -/+ buffers/cache: 841 8789 Swap: 10239 0 10239 php -v PHP 5.3.19 (cli) (built: Nov 28 2012 10:03:07) Copyright (c) 1997-2012 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies with the ionCube PHP Loader v4.2.2, Copyright (c) 2002-2012, by ionCube Ltd., and with Zend Guard Loader v3.3, Copyright (c) 1998-2010, by Zend Technologies with Suhosin v0.9.33, Copyright (c) 2007-2012, by SektionEins GmbH mysql Server version: 5.1.63-cll php -i disable_functions => apache_child_terminate, apache_setenv, define_syslog_variables, escapeshellarg, escapeshellcmd, eval, exec, fp, fput, ftp_connect, ftp_e xec, ftp_get, ftp_login, ftp_nb_fput, ftp_put, ftp_raw, ftp_rawlist, highlight_file, ini_alter, ini_get_all, ini_restore, inject_code, openlog, passthru, php _uname, phpAds_remoteInfo, phpAds_XmlRpc, phpAds_xmlrpcDecode, phpAds_xmlrpcEncode, popen, posix_getpwuid, posix_kill, posix_mkfifo, posix_setpgid, posix_set sid, posix_setuid, posix_setuid, posix_uname, proc_close, proc_get_status, proc_nice, proc_open, proc_terminate, shell_exec, syslog, system, xmlrpc_entity_de code, xmlrpc_server_create, putenv, show_source,mail => apache_child_terminate, apache_setenv, define_syslog_variables, escapeshellarg, escapeshellcmd, eval, exec, fp, fput, ftp_connect, ftp_exec, ftp_get, ftp_login, ftp_nb_fput, ftp_put, ftp_raw, ftp_rawlist, highlight_file, ini_alter, ini_get_all, ini_restore, inject_code, openlog, passthru, php_uname, phpAds_remoteInfo, phpAds_XmlRpc, phpAds_xmlrpcDecode, phpAds_xmlrpcEncode, popen, posix_getpwuid, posix_kill, pos ix_mkfifo, posix_setpgid, posix_setsid, posix_setuid, posix_setuid, posix_uname, proc_close, proc_get_status, proc_nice, proc_open, proc_terminate, shell_exe c, syslog, system, xmlrpc_entity_decode, xmlrpc_server_create, putenv, show_source,mail ... suhosin.executor.disable_eval => Off => Off suhosin.executor.eval.blacklist => include,include_once,require,require_once,curl_init,fpassthru,base64_encode,base64_decode,mail,exec,system,proc_open,leak, syslog,pfsockopen,shell_exec,ini_restore,symlink,stream_socket_server,proc_nice,popen,proc_get_status,dl, pcntl_exec, pcntl_fork, pcntl_signal,pcntl_waitpid, pcntl_wexitstatus, pcntl_wifexited, pcntl_wifsignaled,pcntl_wifstopped, pcntl_wstopsig, pcntl_wtermsig, socket_accept,socket_bind, socket_connect, socket_cr eate, socket_create_listen,socket_create_pair,link,register_shutdown_function,register_tick_function,gzinflate => include,include_once,require,require_once,c url_init,fpassthru,base64_encode,base64_decode,mail,exec,system,proc_open,leak,syslog,pfsockopen,shell_exec,ini_restore,symlink,stream_socket_server,proc_nic e,popen,proc_get_status,dl, pcntl_exec, pcntl_fork, pcntl_signal,pcntl_waitpid, pcntl_wexitstatus, pcntl_wifexited, pcntl_wifsignaled,pcntl_wifstopped, pcntl _wstopsig, pcntl_wtermsig, socket_accept,socket_bind, socket_connect, socket_create, socket_create_listen,socket_create_pair,link,register_shutdown_function, register_tick_function,gzinflate Sometimes i cannot kill httpd process. I run kill -9 PID even several times, and nothing happens. php runs via suphp. I learned somewhere that it can be trojan. I ran strace ps aux and it stops on open("/proc/PID/cmdline", O_RDONLY) If i reboot server, problem is gone but after some time it is back again .. :( Thanks.

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  • Core i7 c1e and speedstepping - BSOD on shutdown

    - by DeaconDesperado
    I'm having an interesting problem with my recent Core i7 Digital Audio workstation build that I am curious to see if others have encountered. First, here are the specs on the machine. ASUS P6TD Deluxe Intel X58 Socket LGA1366 MB Intel Core i7-950 3.06Ghz 8M LGA1366 CPU CORSAIR DOMINATOR 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 Western Digital Caviar Black WD5001AALS 500GB Plus a couple ASUS optical drives and a 750W Corsair PSU. Running Windows 7 x64. All this is connected to the nefarious Digi 002 firewire audio interface for use with Pro Tools. I following mostly the specs posted by many other I7 users in the digidesign community who pooled their collective knowledge in this thread. Now after completing my build, I fell victim to the "UD5 squeal" described at that forum thread. So taking the advice posted, I disabled c1e advanced halt state and Intel speed stepping (I would likely have done this anyway to maintain a stable clock, power consumption isn't really a relevant concern on this machine.) I enabled XMP to set the ram timings properly as well. What I am experiencing is a BSOD upon shutdown, but only immediately after windows fully exits and ends all processes. The error is a MACHINE_CHECK_EXCEPTION 0x000000. The funny thing is that it is extremely intermitent and only occurs if the shutdown immediately followed a period of relative idleness. It does not a generate a minidump, I suspect because windows monitoring has terminated by the time this error occurs. No damage is evident and one can simply turn off manually and the system will act as though a proper shutdown had occurred. If anything it is a annoyance, I just want to be certain it is not affecting my long term stability. I have read that the i7 950 does not like DRAM voltages past 1.65, but that they are acceptable if they are within .5 of the BLCK setting. I have tried disabling XMP and setting all timings to auto and the problem still manifests in an identical way. It is suspect that the cpu idleness preceding shutdown is the determining factor, as both c1e and speedstepping are both settings intended to modify handling of this state. Any suggestions or prior experiences would be greatly appreciated. EDIT: The behavior very closely resembles what's described in this thread: http://www.tomshardware.com/forum/12003-63-shut-problem-windows The benign nature of it of is identical. I can't seem to download the hotfix cited there however.

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  • Baseline / Benchmark Physical and virtual server performance

    - by EyeonTech
    I am setting up a new server and there are some options. I want to perform some benchmarks and I need your help in determining the best tools and if possible run pre-configured benchmarks designed for SQL servers on Windows Server 2008/2012. Step 1. Run a performance monitor on the current Live SQL server (Windows Server 2008 Virtual machine running on ESXi. New server Hardware rundown: Intel® Server System R1304BTLSHBN - 1U Rack, LGA1155 http://ark.intel.com/products/53559/Intel-Server-System-R1304BTLSHBN Intel Xeon E3-1270V2 2x Intel SSD 330 Series 240GB 2.5in SATA 6Gb/s 25nm 1x WD 2TB WD2002FAEX 2TB 64M SATA3 CAVIAR BLACK 4x 8GB 1333MHz DDR3 ECC CL9 DIMM There are several options for configurations and I want to benchmark some of them and share the results. Option 1. Configure 2x SSDs at RAID 0. Install Windows Server 2008 directly to the 2TB WD Caviar HDD. Store Database files on the RAID 0 Volume. Benchmark the OS direct on the hardware as an SQL Server. Store SQL Backup databases on the 2TB WD Caviar HDD. Option 2. Configure 2x SSDs at RAID 0. Install Windows Server 2012 directly to the 2TB WD Caviar HDD. Install Hyper-V. Install the SQL Server (Server 2008) as a virtual machine. Store the Virtual Hard Disks on the SSDs. Option 3. Configure 2x SSDs at RAID 0. Install VMWare ESXi on a partition of the 2TB WD Caviar HDD. Install the SQL Server (Server 2008) as a virtual machine. Store the Virtual Hard Disks on the SSDs. I have a few tools in mind from http://technet.microsoft.com/en-us/library/cc768530(v=bts.10).aspx. Any tools with pre-configured test would be fantastic. Specifically if there are pre-configured perfmon sets avaliable. Any opinions on the setup to gain the best results is welcome. Thanks in advance.

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  • Windows startup Powershell script not closing after Start-Process

    - by Matthew Phipps
    I've got a Powershell V2.0 startup script for my work computer (XP Professional 64-bit), as follows: start "C:\Program Files (x86)\Microsoft Office\Office12\OUTLOOK.EXE" -ArgumentList "/recycle" sleep -S 2 start "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -ArgumentList "https://mail.google.com" sleep -S 2 start "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -ArgumentList "-new-window https://www.google.com/calendar" sleep -S 2 start "C:\Program Files (x86)\Skype\Phone\Skype.exe" The sleeps are to ensure that the windows appear on the taskbar in the correct order. I run this from a shortcut on my Quick Launch with the following Target: C:\WINDOWS\system32\WindowsPowerShell\v1.0\powershell.exe C:\scripts\initialize.ps1 (Yes, this is 2.0: powershell -Version 2.0 works, as does -Version 1.0, but not -Version 3.0) Problem is, the command window stays open until the Firefox windows are closed, which is not what I want. Looking at Process Explorer when I run the script, here's what happens: powershell.exe appears under explorer.exe and the Powershell window appears (with a black background, oddly. But it's not cmd.exe, since when I was debugging the script error messages would appear in red). outlook.exe appears under powershell.exe and the Outlook window appears. firefox.exe appears under powershell.exe and a Firefox window appears. A second firefox.exe appears under powershell.exe and another Firefox window appears. The second Firefox process then exits, as expected, since Firefox only uses one process. skype.exe appears under powershell.exe and the Skype window appears. The powershell.exe process inexplicably sticks around, as does the Powershell window. If I close both Firefox windows, the powershell.exe process exits and the Powershell window closes, and the outlook.exe and skype.exe processes appear under explorer.exe as expected. I suspect this has something to do with Firefox's standard input, output and error: I wouldn't expect Outlook or Skype to ever output anything to the console, but Firefox has command-line options that allow it to do so. I've looked over my about:config's user set values and didn't find anything suspicious. Finally, if I have a firefox.exe instance already running (started from the desktop shortcut) the problem doesn't occur (the powershell.exe process exits as it ought to). So what's going on here? I'm going to try adding -WindowStyle hidden to the shortcut next (gotta close this Firefox to test it), but I want to get to the bottom of this, if only to improve my understanding of how Windows consoles work.

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  • WIndows 7 cannot boot - bootrec reports FS not found or corrupt

    - by purecharger
    For 3 days now I've been unable to boot into my Windows 7 partition, and all my research has been to no avail. I'm hoping someone here has more ideas on how to fix this. When I boot up now, I get the black screen with BCD error that says theres no valid file system or it may be corrupt (pardon my lack of detail, no copy/paste is available then). When I boot with the Windows 7 disc and go into repair tools, no operating system is found, and attempting to automatically repair the problem fails with Unknown Operating System (Unknown Disk) or something similar. When I drop into the command prompt, I am able to see and navigate my C:\ drive without issue. I attempt to use bootrec: C:\> bootrec /ScanOS Finds C:\Windows as a system partition. C:\> bootrec /RebuildBCD Fails with volume does not contain a recognized file system. please make sure that all required file system drivers are loaded and that the volume is not corrupted. So then I attempt to fix the bootsector: C:\> bootsect /nt60 C: /force Which completes successfully (sorry, no output..) Upon rebooting, I have the same problem. I've also tried all of the above after making my Windows partition active: C:\> diskpart DISKPART> select disk 1 DISKPART> select partition 1 DISKPART> active DISKPART> exit Then bootrec as above, both with and without a reboot after the DISKPART commands. Then I've also tried rebuilding the BCD store by hand: set systemdrive=C: set tempbcd=C:\boot\bcd.temp set tempfile=C:\boot\temp.txt bcdedit -createstore %tempbcd% bcdedit.exe -store %tempbcd% -create {bootmgr} -d "Windows Boot Manager" bcdedit -store %tempbcd% -create -d "Windows Vista" -application osloader>%tempfile% set /p winvistaguid= <%tempfile% set winvistaguid=%winvistaguid:~10,38% bcdedit -store %tempbcd% -set %winvistaguid% osdevice partition=%systemdrive% bcdedit -store %tempbcd% -set %winvistaguid% device partition=%systemdrive% bcdedit -store %tempbcd% -set %winvistaguid% path \Windows\system32\winload.exe bcdedit -store %tempbcd% -set %winvistaguid% systemroot \Windows bcdedit -import %tempbcd% However on the import, I get my familiar friendly message: volume does not contain a recognized file system. please make sure that all required file system drivers are loaded and that the volume is not corrupted I'm at my wits end here, and I cannot understand why Windows refuses to see this as a valid install. When I list the disk/partition in DISKPART, it shows up as NTFS and "Healthy", and I can navigate the directory structure from DOS with no problems. I really, really do not want to reformat and reinstall. I know this problem can be solved!

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  • WIndows 7 cannot boot - bootrec reports FS not found or corrupt

    - by purecharger
    For 3 days now I've been unable to boot into my Windows 7 partition, and all my research has been to no avail. I'm hoping someone here has more ideas on how to fix this. When I boot up now, I get the black screen with BCD error that says theres no valid file system or it may be corrupt (pardon my lack of detail, no copy/paste is available then). When I boot with the Windows 7 disc and go into repair tools, no operating system is found, and attempting to automatically repair the problem fails with Unknown Operating System (Unknown Disk) or something similar. When I drop into the command prompt, I am able to see and navigate my C:\ drive without issue. I attempt to use bootrec: C:\> bootrec /ScanOS Finds C:\Windows as a system partition. C:\> bootrec /RebuildBCD Fails with volume does not contain a recognized file system. please make sure that all required file system drivers are loaded and that the volume is not corrupted. So then I attempt to fix the bootsector: C:\> bootsect /nt60 C: /force Which completes successfully (sorry, no output..) Upon rebooting, I have the same problem. I've also tried all of the above after making my Windows partition active: C:\> diskpart DISKPART> select disk 1 DISKPART> select partition 1 DISKPART> active DISKPART> exit Then bootrec as above, both with and without a reboot after the DISKPART commands. Then I've also tried rebuilding the BCD store by hand: set systemdrive=C: set tempbcd=C:\boot\bcd.temp set tempfile=C:\boot\temp.txt bcdedit -createstore %tempbcd% bcdedit.exe -store %tempbcd% -create {bootmgr} -d "Windows Boot Manager" bcdedit -store %tempbcd% -create -d "Windows Vista" -application osloader>%tempfile% set /p winvistaguid= <%tempfile% set winvistaguid=%winvistaguid:~10,38% bcdedit -store %tempbcd% -set %winvistaguid% osdevice partition=%systemdrive% bcdedit -store %tempbcd% -set %winvistaguid% device partition=%systemdrive% bcdedit -store %tempbcd% -set %winvistaguid% path \Windows\system32\winload.exe bcdedit -store %tempbcd% -set %winvistaguid% systemroot \Windows bcdedit -import %tempbcd% However on the import, I get my familiar friendly message: volume does not contain a recognized file system. please make sure that all required file system drivers are loaded and that the volume is not corrupted I'm at my wits end here, and I cannot understand why Windows refuses to see this as a valid install. When I list the disk/partition in DISKPART, it shows up as NTFS and "Healthy", and I can navigate the directory structure from DOS with no problems. I really, really do not want to reformat and reinstall. I know this problem can be solved!

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  • Transient network dropout for Xen DomU's

    - by Stephen C
    We've got a CentOS server running a cluster of virtuals. Occasionally the cluster's internal network drops out for a minute or so ... and then comes back. The problem is somehow related to the actual network traffic, but it is not a simple load issue. (The system is generally lightly loaded, and the problem occurs irrespective of actual load.) The setup: CentOS 5.6 on Dom0, various CentOS on the DomU's Hardware - a Dell R710 with a BroadCom NextXpress 2 NIC (sigh) using the latest drivers for the NIC from BroadCom Xen configured to use network-bridge and vif-bridge Some iptable tweaks to route an unrelated port to one of the virtuals. The system has one externally visible IP address, and Dom0 runs an Apache httpd configured with a number of virtual hosts each of which reverse proxies to web servers running on the virtuals. (The virtuals have to be NAT'ed, primarily because we don't have enough allocated public IP addresses.) The symptoms: Works fine most of the time. When someone tries to UPLOAD a large file to one virtuals, the internal network drops out ... for all virtuals: The Dom0 httpd sees a network timeout talking to the backend server on the virtual and reports a 502. A previously established ssh connection from Dom0 to any of the DomU's freezes. Our monitoring shows ping failures for traffic between virtuals. The Xen consoles to the DomU's do not freeze. No log messages in any log files that I can see, on either Dom0 or the DomU's ... apart from the Dom0 httpd logs. After a minute or so, the problem clears by itself. This is 100% reproducible. What we've tried: Downloading, building and installing the latest BNX2 driver on Dom0 Turning off MSI on the NIC - adding "options bnx2 disable_msi=1" to /etc/modprobe.conf Turning off tcp segmentation offload - "ethtool -K eth0 tso off". Sacrificing a black rooster at midnight. I've exhausted all my options apart from switching to KVM ... or slaughtering more roosters. Any suggestions?

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  • Script to check a shared Exchange calendar and then email detail

    - by SJN
    We're running Server and Exchange 2003 here. There's a shared calendar which HR keep up-to-date detailing staff who are on leave. I'm looking for a VB Script (or alternate) which will extract the "appointment" titles of each item for the current day and then email the detail to a mail group, in doing so notifying the group with regard to which staff are on leave for the day. The resulting email body should be: Staff on leave today: Mike Davis James Stead @Paul Robichaux - ADO is the way I went for this in the end, here are the key component for those interested: Dim Rs, Conn, Url, Username, Password, Recipient Set Rs = CreateObject("ADODB.Recordset") Set Conn = CreateObject("ADODB.Connection") 'Configurable variables Username = "Domain\username" ' AD domain\username Password = "password" ' AD password Url = "file://./backofficestorage/domain.com/MBX/username/Calendar" 'path to user's mailbox and folder Recipient = "[email protected]" Conn.Provider = "ExOLEDB.DataSource" Conn.Open Url, Username, Password Set Rs.ActiveConnection = Conn Rs.Source = "SELECT ""DAV:href"", " & _ " ""urn:schemas:httpmail:subject"", " & _ " ""urn:schemas:calendar:dtstart"", " & _ " ""urn:schemas:calendar:dtend"" " & _ "FROM scope('shallow traversal of """"') " Rs.Open Rs.MoveFirst strOutput = "" Do Until Rs.EOF If DateDiff("s", Rs.Fields("urn:schemas:calendar:dtstart"), date) >= 0 And DateDiff("s", Rs.Fields("urn:schemas:calendar:dtend"), date) < 0 Then strOutput = strOutput & "<p><font size='2' color='black' face='verdana'><b>" & Rs.Fields("urn:schemas:httpmail:subject") & "</b><br />" & vbCrLf strOutput = strOutput & "<b>From: </b>" & Rs.Fields("urn:schemas:calendar:dtstart") & vbCrLf strOutput = strOutput & "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<b>To: </b>" & Rs.Fields("urn:schemas:calendar:dtend") & "<br /><br />" & vbCrLf End If Rs.MoveNext Loop Conn.Close Set Conn = Nothing Set Rec = Nothing After that, you can do what you like with srtOutput, I happened to use CDO to send an email: Set objMessage = CreateObject("CDO.Message") objMessage.Subject = "Subject" objMessage.From = "[email protected]" objMessage.To = Recipient objMessage.HTMLBody = strOutput objMessage.Send S

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  • How to encrypt dual boot windows 7 and xp (bitlocker, truecrypt combo?) on sdd (recommended?)

    - by therobyouknow
    I would like to setup a dual boot Windows 7 and Windows XP laptop/notebook computer where each operation system's partition is fully encrypted. I would like to do this on a SSD - a 128Gb Crucial M4. My research Dual boot of truecrypt encrypted OSs on one drive (not possible - in Truecript 7.x at time of writing) This cannot be done on a standard Truecrypt setup - it will only support encrypting one of the operating systems. I have tried this and also read about it here on superuser.com However, I did see a solution here that uses grub4dos as the initial bootloader to chain to separate truecrypt encrypted OSs, in my case Windows 7 and Windows XP: http://yyzyyz.blogspot.co.uk/2010/06/truecrypt-how-to-encrypt-multiple.html I am not going to consider this solution as it relies upon some custom code for use in the bootloader that is provided by the author. I would prefer a solution that can be fully understood so that I can be sure that there is nothing undesirable occuring (i.e. malware or just simply bugs in the code). I would like to believe such a solution doesn't have those risks but I can't be sure. BitLocker and Truecrypt combination - possible solution? So I am now considering a combination of encryption programs: I now aim to encrypt Windows XP with Truecrypt and Windows 7 with BitLocker. Assuming Truecrypt bootloader can boot into non-Truecrypt OSs (e.g. via hitting Escape to go to another menu), then this solution may be viable. SSDs and Encryption (use fastest possible spinning hard disk instead (?)) I read on various superuser.com posts and elsewhere that current SSDs are not suited to whole drive encryption for various reasons: impact of performance algorithms that give SSDs advantage over spinning harddisks. Algorithms used in compression of data for example. Wear on the SSD, shortening its life Security issues whereby data is repeated, as indicated in some Truecrypt documentation So I am now considering not using SSD. But with the aim to have the fastest drive possible, I am considering using the Western Digital Scorpion black 2.5" 7200rpm harddisk as this appears to be top rated among spinning platter-based harddrives (don't work for Western Digital). Summary So to achieve whole drive encrypted dual boot Windows 7 and Windows XP with minimal performance impact I intend to use a combination of Truecrypt and Bitlocker on a top-rated conventional spinning platter-based harddisk. Questions Will my summary: achieve whole disk encryption of the dual-boot Windows XP, Windows 7? OR an you suggest a simpler solution, including one that only requires only Truecrypt (BitLocker not available on XP). Or another encryption tool, including paid-for? provide the highest performance. Am I correct to avoid using SDD with encryption for the reasons I discovered? Are the concerns about SSDs and encryption still very real (some articles I read go back to 2010) Thanks for your input!

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  • Graphics card artifacting

    - by White Phoenix
    This is my current build: EVGA X58 (first generation) motherboard Intel i7 965 @ stock clocks 3x 2GB DDR3-1600 Corsair RAM at stock timings and voltages Corsair AX750 80 Plus Gold PSU 1 Optical Drive 1 Seagate 7200.10 500 GB drive 2x Western Digital Caviar Black 1 TB drives OCZ Vertex 1 60 GB EVGA GTX 460 Antec 1200 case HT-Omega Striker 7.1 Sound Card Windows 7 32-bit Professional (PAE Enabled) My graphics card started artifacting while I was playing a game. It artifacted, the display blinked, then I got an NVIDIA driver has crashed and recovered message. Kept going, more artifacts, another crash, but this time my display blanked out and I couldn't do anything. Restarted my computer - artifacting is in the BIOS - got to Windows 7 but it BSOD'd before I could even log in. I restarted the computer again - artifacts cleared themselves out and I managed to get to Win7, but it soon started blinking in and out and artifacting again. Checked the card temps and they're well within range. (50 idle, 70 full load) The ambient temperature here is about 80-85F with high humidity. Tried Safe Mode and it still froze up/BSOD'd. Already tried the following to fix this problem: - Reseat the graphics card and swapped in a different slot. - Removed cover on card and sprayed with compressed air to clean it out. - Swapped around memory and/or went with only using one stick at a time. - Underclocked card I called EVGA Tech Support and they said that the voltage on the 12V rail of my Corsair AX750 PSU was on the high end of the "acceptable" range (12.4V, highest within acceptable range is 12.6V - optimal is obviously 12V). They gave me an RMA number anyway, but I want to get a second opinion from you all before I send this thing off, as shipping from where I live to EVGA is kind of pricey. This PSU is only 6 months old. So that I don't have to play RMA tag, which case would be most likely? I'm strapped for cash at the moment so I want to reduce the amount of RMAs I have to do since shipping is expensive here. Is there any surefire way to test to see if it's really the graphics card or the PSU? I tried unplugging any devices that were connected to the 12V rail (except for my SSD and graphics card) as I do have 3 mechanical hard drives, but the voltage for that rail didn't drop (it remained at 12.4V). I'm fairly sure it isn't the drivers since I'm getting the artifacting at the BIOS too. Right now I'm back in Windows 7 but I don't know for how long until it messes up again. Any ideas?

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  • Well....a ghost lives in my server...

    - by tsgiannis
    Hello to every body and greetings from Greece I have a rather unusual situation and i am running out of ideas. I have this old server (IBM x205 - P4 2.4Ghz,3xSCSI 36gb) and i was about a year ago i decided to use it as an additional domain controller,fax & file server...for this task i had a Delock 70154 SATA card along with 2x320 SATA II HDDs Everything was going super smoothly until about 3 weeks ago. I was on a trip and i was informermed when i got back that the server was found frozen...well i considered it was a glitch since a simple powerdown power up fixed everything.Again 2 weeks ago another freeze situation....it got suspicious but again power down power up everything was running.... Last again it frozen and when i power it up it came with a message that the Domain services could not start due to NTDS corruption....booting in safe mode revealed that there was an issue with the SATA Raid (degraded). After a lot of searching i degraded the server...cleaned Active Directory and pulled both HDDs out (one of these was really BAD ) and recovered my files (i had some problems with ho Delock handles the redudant HDD). Right now my server is vanilla simple...with only what the factory installed and here is where the fun begins. Everyday when i arrive at the office i find this particular machine dead..and i mean total dead...just a black screen and nothing else...the cpu fan is working ,the psu is working .keyboard and mouse are dead(they also lock my kvm) ...network is dead.... the machine is DEAD. I power it down forcilly ...i power it up and for the 8 hours i am in the office it works,either idling or running some kind of diagnostic...when i leave the office after some time..it maybe half an hour ...it maybe 4 hours the machine dies...at least this is the information the event log shows (" the previous shutdown at xx:xx:xx was unexpected) Well i must admit i am runnig out of ideas.... I have tried Memtest....nothing Passmark burn in test.....nothing Carefull study of the event log.....nothing Set Instead of restart..BSOD....nothing Power sceheme to sleep...all set to never. i know there are a lot of other tools that heavily stress a machine like occt but .... the machine is old...today i will give them a try nevertheless ..... One idea is to reformat it...but ... i really like to find what is causing this because i could get to a situation that everything is working for a while and kaboom...one day again is dying.. I really need a helping hand and every opinion / idea is well welcomed.... iknow the obvious solution is to never leave the office but....i have a life...sory server...:) P.S this situation with the machine dying some time after is going on for about one week...everyday i would set either the RAID to rebuild....or to copy/recover files and while everythig was working

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  • Windows server detected error with hard disk

    - by user53864
    We have hosting Windows server 2008 R2 and I am working as admin in small company. The server is hanging and restarting as the hard disk seems to be damaged due to power fluctutaion(though having inverter) as it's showing the below error message on server reboot: Problem detected with the hard disk Press any key to continue It's Seagate 1TB SATA hard disk and it's booting after pressing enter. So it's clear that the hard disk is dying. Yes, it's in warranty but it's fact that warranty won't recover the lincesed windows server 2008 and it's data. As it's booting now, I backed up required things and I am thinking to clone the entire hard disk. The first thing it striked me is checking on the Seagate site if any tool available for cloning and I found Seagate DiskWizard but not specified it for windows server 2008. Please anybody could help me giving your best ideas for the below: Urgently, What's the best way(free of cost) for me to clone in my case with the new same sized hard disk? It's a one time lincenced and I cannot use the same key again if I reinstall the server. Will the lincense be carried with new disk if cloned? else there is a way to contact Microsoft explaining the problem occurred, to obtain new key for no charge?. I want to take measure for future. How do I keep two disks in continuous sync? mirrored & raid are the only options converting the disks to dynamic? or is there a best way I could do with no additional charge?. Any help is greatly appreciated. Thank you! EDIT:1 I started cloning the disk with CloneZilla and it was going proper showing in GUI. But after some time there is no GUI but a black screen with some codes(looks like disk location numbers) going page by page(I have attached the screenshots below captured from my phone). Do you people think it's actually cloning?. I started in the morning and it's evening now. I left the office now to let it finish what it's trying to do and I'll go & check it tomorrow. Slowly lost hope, don't know what face it's going to show tomorrow. Any ideas?

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  • Cannot access boot menu with compaq 8510p

    - by pinouchon
    I have a problem with my HP compaq 8510p laptop: when I start it, the fan starts and the power light is on, but the screen displays nothing. When I insert a bootable hard drive, it activates the hard drive light (meaning that the CD is recognized) but it stops after a few seconds. Same thing with any hard drive: the drive is recognized but does not boot. What I've tried so far: Changing the hard drive or booting with no hard drive (same problem) Plugging anoher display via VGA : no display on the other screen Inserting a windows-7 CD (same problem) Booting only on battery, with battery and power cable, only with power cable (same problem) So it looks like something is preventing the laptop from booting and displaying the boot menu. Do you have experienced something similar with a laptop ? What could be wrong ? The laptop is out of warranty. The system used to be windows-7 x64. Edit: I went to the help desk of my university. A guy took a look (he also tried to plug an external screen) and said that the computer is dead: on the HP laptops eventually the GPU card dies and so does the motherboard because they are linked. He saw this many times, and even if I can fix the problem, the laptop would crash again after a while. Do you have similar experience with HP laptops ? (mine is 4 years old) Edit 2: Believe it or not, my laptop is magically working again. I have no clue about what is going on. Now it is like starting and old car: when you turn it on you secretly hope it will actually start... With that said, I expect my laptop to break again in the near future (its an HP after all) and I will accept an answer or add my own accordingly. Edit 3: As expected, the laptop is down again. This time, sometimes when I power it up, it shuts down automatically after 3 seconds, sometimes not at all. In addition, when it does not shut down on its own, the power button does not work : the only way to shut it down is by unplugging the battery. As before, the screen is black, and only the power and battery lights are on. (the other ones: hard drive and wifi are off). I have tried to plug in another power plug, removing the battery and removing the hard drive without success. I might buy another laptop. I've brought the laptop to a repair shop. The problem is indeed that the graphic card is down. It will be replaced by a new one.

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  • My USB bootable thumb drive, no longer boots on a single particular computer on which it previously worked

    - by LiamMeron
    I created a bootable drive, booting CrunchBang, about 2 months ago. About a month ago, I booted into it on another laptop. After shutting down, I have been unable to get it to boot on my own laptop, despite having worked previously. I can still boot into it on my desktop, and can also boot into it on all other computers that I have tried. If I plug it in when I am running Ubuntu, the Home and / folders mount, the only error being that for some reason my PC likes to try and mount the swap partition too, which naturally, gives an error. The BIOS settings are all still setup to boot from USB. When I boot, all I get is a black screen with the white cursor, it will stay there for as long as I leave it. If it is worth anything, I have GRUB loader installed on the drive. The partitions look a little odd, but I am rather unfamiliar with how they are dealt with. The first partition, /, is sdb1 and has the bootable flag. The second partition is an extended system, and is sdb2. The third partition, according to GParted, seems to be nested under the second. This is the swap partition, and it is sdb5 The fourth partition is my home partition and is sdb6 and is also nested under the extended system. The first and fourth partitions are ext4. I don't know if that helps, but the more info, the better accuracy, generally. Thanks. EDIT: I tried reinstalling GRUB on the drive, but that didn't work. However, when I reinstalled GRUB on my laptop, I did it with my USB thumbdrive in. This caused the GRUB updater to find the /boot folder and add the proper details into my laptop's GRUB loader. I could log into CrunchBang from my laptop's GRUB but I was still unable to boot directly to the drive. It looked like my BIOS is unable to find the bootloader. I am unable to install GRUB to a partition I just created, a /boot partition at the start of the drive, GRUB just doesn't allow it. I think I'm going to have to reinstall #! on my drive, which won't be a great loss as I haven't put much time into it.

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  • Bridging and iptables SNAT conflict

    - by sad_admin
    Hello I am working on a setup here and have it working with one minor exception. Devices on one side of my bridge aren't getting SNAT'd to the Internet. The Diagram / Overview: Primary_Network (Site_A) | | Internet ------- Linux_Bridge_GW (GW) | | Secondary/CoLo Site (Site_B) Here is the setup: 1.) Site_A has all the production servers and workstations. 2.) Site_B has a set of servers that we would like to fail-over to and also serve our internet facing services from. 3.) GW has two interfaces that are trunked and carrying the appropriate VLAN traffic (allow layer-2 propagation of traffic between sites) //this all works perfectly fine. 4.) The problem that is being encountered is, hosts from Site_B have their default GW at Site_A (same subnet) GW does not have IPs on the VLANs that are being passed. 5.) All hosts at Site_A can reach the Internet without problem. 6.) GW has an addresses on a subnet that is ONLY for Internet destined traffic. (This was done so that Websense would not have to parse unnecessary traffic. We use this VLAN as the monitor port's source on the switch where Websense is sitting). What I think is happening: 1.) Packet/Frame comes in on physdev at Site_B destined for Internet. 2.) Kernel sees packet, and forwards it out the other side of the bridge to that host's default GW. 3.) Site_A (containing core-network's Default-GW) sees that packet is destined for a host it doesn't know about, so it sends it to it's default GW (the linux bridge, since it's Internet bound). 4.) The kernel says "Hey, I've seen you before" and therefore doesn't do SNAT'ing on the packet and sends it out to the Internet where it's black-holed. Why I think it's happening: 1.) A tcpdump on the internet facing NIC shows the packet leaving the interface with the private address as it's source. What I would like: 1.) Have the packet SNAT'd. 2.) Something like the below would be awesome a.) packet comes in from Site_B b.) kernel sees that the packet is NOT destined for itself or any private address c.) kernel says "OK, well since you're destined for the Internet I'm going to send you out this interface rather than forward you to your normal default GW that's WAAAY over there." d.) packet comes in from internet and is sent out the appropriate bridge physdev depending on which site the host it's destined for is at. Thanks for any assistance or guidance that you are willing to offer. Best Regards, Sad Admin

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  • Lenovo Windows 8 EFI restore from image

    - by anderhil
    First time here. I have bought e530 with windows 8 and the first hour of work with it i have a problem. I have ssd with windows 7 which i want to use with my new e530. I have made a sysprep of win 7 and installed ssd to the e530. The HDD which was inside e530 i want to use as second hdd instead of my DVD Drive. I connected this HDD through usb-to-sata adapter to copy some files from ssd to the hdd. Unfortunately it didn't see the file system on the HDD (but first time i have booted to it and first boot into Windows 8) I've made some mistakes and i corrupt the filesystem on the hdd. I tried bunch of tricks to recover the GPT, but it didn't work. I have managed to recover the Lenovo_Recovery partition to my ssd using recovery tools. And now I'm stuck, with this new things to me - EFI, GPT, etc i don't how this stuff works, and i have been trying to understand this for hours - but nothing seems to work. I want to restore the Windows 8 to the hdd, so it is there alive. What i have done so far: Formated the HDD I took the PBRALL file from the Lenovo_Recovery " convert gpt create partition Primary size=1000 ID=DE94BBA4-06D1-4D40-A16A-BFD50179D6AC gpt attributes=0x8000000000000001 assign letter=W format quick LABEL=WINRE_DRV create partition efi size=260 assign letter=s format quick fs=fat32 LABEL=SYSTEM_DRV create par msr size=128 create partition primary noerr assign letter=t format quick LABEL=Windows8_OS shrink desired=12197 create partition Primary ID=DE94BBA4-06D1-4D40-A16A-BFD50179D6AC gpt attributes=0x8000000000000001 assign letter=q format quick LABEL=Lenovo_Recovery " it recreated the partitions copied contents of SDRIVE.zip to SYSTEM_DRV partition copied contents of WDRIVE.zip to WINRE_DRV partition Copied restored Lenovo_Recovery back to Lenovo_Recovery partition So now I have 3 system partitions: SYSTE_DRV BOOT boot.sdi EFI BOOT bootx64.efi LenovoBT.efi Lenovo ... Microsoft ... WINRE_DRV\Recovery\WindowsRE\winre.wim Lenovo_Recovery (whic contains install.wim and bunch of other things) So i put back the HDD inside the laptop and tried to boot - but nothing works. It just doesn't boot to anything - no errors - nothing at all. When I choose this HDD manually for boot - just black screen blinks and that's all - it returns back to the devices boot menu. SYSTEM_DRV is EFI partition, so I don't understand why it doesn't boot, it has files needed inside. Can anybody tell me what should be done to make it boot to recovery console or smth like that? How to restore the Windows 8 from the Lenovo_Recovery install.wim image? As I understand I have all the files where they should be, but why it doesn't work? How to troubleshoot such things? Also, if somebody has good link where EFI booting process is explained in details that would be great. Cause i still don't understand how it knows what partition to boot?

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  • C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

    - by Reed
    Today’s announcement at PDC of the future directions C# is taking excite me greatly.  The new Visual Studio Async CTP is amazing.  Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability.  This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await. This core of the new asynchronous functionality is built upon three key features.  First is the Task functionality in .NET 4, and based on Task and Task<TResult>.  While Task was intended to be the primary means of asynchronous programming with .NET 4, the .NET Framework was still based mainly on the Asynchronous Pattern and the Event-based Asynchronous Pattern. The .NET Framework added functionality and guidance for wrapping existing APIs into a Task based API, but the framework itself didn’t really adopt Task or Task<TResult> in any meaningful way.  The CTP shows that, going forward, this is changing. One of the three key new features coming in C# is actually a .NET Framework feature.  Nearly every asynchronous API in the .NET Framework has been wrapped into a new, Task-based method calls.  In the CTP, this is done via as external assembly (AsyncCtpLibrary.dll) which uses Extension Methods to wrap the existing APIs.  However, going forward, this will be handled directly within the Framework.  This will have a unifying effect throughout the .NET Framework.  This is the first building block of the new features for asynchronous programming: Going forward, all asynchronous operations will work via a method that returns Task or Task<TResult> The second key feature is the new async contextual keyword being added to the language.  The async keyword is used to declare an asynchronous function, which is a method that either returns void, a Task, or a Task<T>. Inside the asynchronous function, there must be at least one await expression.  This is a new C# keyword (await) that is used to automatically take a series of statements and break it up to potentially use discontinuous evaluation.  This is done by using await on any expression that evaluates to a Task or Task<T>. For example, suppose we want to download a webpage as a string.  There is a new method added to WebClient: Task<string> WebClient.DownloadStringTaskAsync(Uri).  Since this returns a Task<string> we can use it within an asynchronous function.  Suppose, for example, that we wanted to do something similar to my asynchronous Task example – download a web page asynchronously and check to see if it supports XHTML 1.0, then report this into a TextBox.  This could be done like so: private async void button1_Click(object sender, RoutedEventArgs e) { string url = "http://reedcopsey.com"; string content = await new WebClient().DownloadStringTaskAsync(url); this.textBox1.Text = string.Format("Page {0} supports XHTML 1.0: {1}", url, content.Contains("XHTML 1.0")); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Let’s walk through what’s happening here, step by step.  By adding the async contextual keyword to the method definition, we are able to use the await keyword on our WebClient.DownloadStringTaskAsync method call. When the user clicks this button, the new method (Task<string> WebClient.DownloadStringTaskAsync(string)) is called, which returns a Task<string>.  By adding the await keyword, the runtime will call this method that returns Task<string>, and execution will return to the caller at this point.  This means that our UI is not blocked while the webpage is downloaded.  Instead, the UI thread will “await” at this point, and let the WebClient do it’s thing asynchronously. When the WebClient finishes downloading the string, the user interface’s synchronization context will automatically be used to “pick up” where it left off, and the Task<string> returned from DownloadStringTaskAsync is automatically unwrapped and set into the content variable.  At this point, we can use that and set our text box content. There are a couple of key points here: Asynchronous functions are declared with the async keyword, and contain one or more await expressions In addition to the obvious benefits of shorter, simpler code – there are some subtle but tremendous benefits in this approach.  When the execution of this asynchronous function continues after the first await statement, the initial synchronization context is used to continue the execution of this function.  That means that we don’t have to explicitly marshal the call that sets textbox1.Text back to the UI thread – it’s handled automatically by the language and framework!  Exception handling around asynchronous method calls also just works. I’d recommend every C# developer take a look at the documentation on the new Asynchronous Programming for C# and Visual Basic page, download the Visual Studio Async CTP, and try it out.

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  • Parallelism in .NET – Part 13, Introducing the Task class

    - by Reed
    Once we’ve used a task-based decomposition to decompose a problem, we need a clean abstraction usable to implement the resulting decomposition.  Given that task decomposition is founded upon defining discrete tasks, .NET 4 has introduced a new API for dealing with task related issues, the aptly named Task class. The Task class is a wrapper for a delegate representing a single, discrete task within your decomposition.  We will go into various methods of construction for tasks later, but, when reduced to its fundamentals, an instance of a Task is nothing more than a wrapper around a delegate with some utility functionality added.  In order to fully understand the Task class within the new Task Parallel Library, it is important to realize that a task really is just a delegate – nothing more.  In particular, note that I never mentioned threading or parallelism in my description of a Task.  Although the Task class exists in the new System.Threading.Tasks namespace: Tasks are not directly related to threads or multithreading. Of course, Task instances will typically be used in our implementation of concurrency within an application, but the Task class itself does not provide the concurrency used.  The Task API supports using Tasks in an entirely single threaded, synchronous manner. Tasks are very much like standard delegates.  You can execute a task synchronously via Task.RunSynchronously(), or you can use Task.Start() to schedule a task to run, typically asynchronously.  This is very similar to using delegate.Invoke to execute a delegate synchronously, or using delegate.BeginInvoke to execute it asynchronously. The Task class adds some nice functionality on top of a standard delegate which improves usability in both synchronous and multithreaded environments. The first addition provided by Task is a means of handling cancellation via the new unified cancellation mechanism of .NET 4.  If the wrapped delegate within a Task raises an OperationCanceledException during it’s operation, which is typically generated via calling ThrowIfCancellationRequested on a CancellationToken, or if the CancellationToken used to construct a Task instance is flagged as canceled, the Task’s IsCanceled property will be set to true automatically.  This provides a clean way to determine whether a Task has been canceled, often without requiring specific exception handling. Tasks also provide a clean API which can be used for waiting on a task.  Although the Task class explicitly implements IAsyncResult, Tasks provide a nicer usage model than the traditional .NET Asynchronous Programming Model.  Instead of needing to track an IAsyncResult handle, you can just directly call Task.Wait() to block until a Task has completed.  Overloads exist for providing a timeout, a CancellationToken, or both to prevent waiting indefinitely.  In addition, the Task class provides static methods for waiting on multiple tasks – Task.WaitAll and Task.WaitAny, again with overloads providing time out options.  This provides a very simple, clean API for waiting on single or multiple tasks. Finally, Tasks provide a much nicer model for Exception handling.  If the delegate wrapped within a Task raises an exception, the exception will automatically get wrapped into an AggregateException and exposed via the Task.Exception property.  This exception is stored with the Task directly, and does not tear down the application.  Later, when Task.Wait() (or Task.WaitAll or Task.WaitAny) is called on this task, an AggregateException will be raised at that point if any of the tasks raised an exception.  For example, suppose we have the following code: Task taskOne = new Task( () => { throw new ApplicationException("Random Exception!"); }); Task taskTwo = new Task( () => { throw new ArgumentException("Different exception here"); }); // Start the tasks taskOne.Start(); taskTwo.Start(); try { Task.WaitAll(new[] { taskOne, taskTwo }); } catch (AggregateException e) { Console.WriteLine(e.InnerExceptions.Count); foreach (var inner in e.InnerExceptions) Console.WriteLine(inner.Message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, our routine will print: 2 Different exception here Random Exception! Note that we had two separate tasks, each of which raised two distinctly different types of exceptions.  We can handle this cleanly, with very little code, in a much nicer manner than the Asynchronous Programming API.  We no longer need to handle TargetInvocationException or worry about implementing the Event-based Asynchronous Pattern properly by setting the AsyncCompletedEventArgs.Error property.  Instead, we just raise our exception as normal, and handle AggregateException in a single location in our calling code.

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  • Parallelism in .NET – Part 16, Creating Tasks via a TaskFactory

    - by Reed
    The Task class in the Task Parallel Library supplies a large set of features.  However, when creating the task, and assigning it to a TaskScheduler, and starting the Task, there are quite a few steps involved.  This gets even more cumbersome when multiple tasks are involved.  Each task must be constructed, duplicating any options required, then started individually, potentially on a specific scheduler.  At first glance, this makes the new Task class seem like more work than ThreadPool.QueueUserWorkItem in .NET 3.5. In order to simplify this process, and make Tasks simple to use in simple cases, without sacrificing their power and flexibility, the Task Parallel Library added a new class: TaskFactory. The TaskFactory class is intended to “Provide support for creating and scheduling Task objects.”  Its entire purpose is to simplify development when working with Task instances.  The Task class provides access to the default TaskFactory via the Task.Factory static property.  By default, TaskFactory uses the default TaskScheduler to schedule tasks on a ThreadPool thread.  By using Task.Factory, we can automatically create and start a task in a single “fire and forget” manner, similar to how we did with ThreadPool.QueueUserWorkItem: Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides us with the same level of simplicity we had with ThreadPool.QueueUserWorkItem, but even more power.  For example, we can now easily wait on the task: // Start our task on a background thread var task = Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); // Do other work on the main thread, // while the task above executes in the background this.ExecuteWorkSynchronously(); // Wait for the background task to finish task.Wait(); TaskFactory simplifies creation and startup of simple background tasks dramatically. In addition to using the default TaskFactory, it’s often useful to construct a custom TaskFactory.  The TaskFactory class includes an entire set of constructors which allow you to specify the default configuration for every Task instance created by that factory.  This is particularly useful when using a custom TaskScheduler.  For example, look at the sample code for starting a task on the UI thread in Part 15: // Given the following, constructed on the UI thread // TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // When inside a background task, we can do string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); This is actually quite a bit more complicated than necessary.  When we create the uiScheduler instance, we can use that to construct a TaskFactory that will automatically schedule tasks on the UI thread.  To do that, we’d create the following on our main thread, prior to constructing our background tasks: // Construct a task scheduler from the current SynchronizationContext (UI thread) var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Construct a new TaskFactory using our UI scheduler var uiTaskFactory = new TaskFactory(uiScheduler); If we do this, when we’re on a background thread, we can use this new TaskFactory to marshal a Task back onto the UI thread.  Our previous code simplifies to: // When inside a background task, we can do string status = GetUpdatedStatus(); // Update our UI uiTaskFactory.StartNew( () => statusLabel.Text = status); Notice how much simpler this becomes!  By taking advantage of the convenience provided by a custom TaskFactory, we can now marshal to set data on the UI thread in a single, clear line of code!

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  • Tweaking a few URL validation settings on ASP.NET v4.0

    - by Carlyle Dacosta
    ASP.NET has a few default settings for URLs out of the box. These can be configured quite easily in the web.config file within the  <system.web>/<httpRuntime> configuration section. Some of these are: <httpRuntime maxUrlLength=”<number here>”. This number should be an integer value (defaults to 260 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. This attribute gates the length of the Url without query string. <httpRuntime maxQueryStringLength=”<number here>”. This number should be an integer value (defaults to 2048 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. <httpRuntime requestPathInvalidCharacters=”List of characters you need included in ASP.NETs validation checks”. By default the characters are “<,>,*,%,&,:,\,?”. However once can easily change this by setting by modifying web.config. Remember, these characters can be specified in a variety of formats. For example, I want the character ‘!’ to be included in ASP.NETs URL validation logic. So I set the following: <httpRuntime requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,!”. A character could also be specified in its xml encoded form. ‘&lt;;’ would mean the ‘<’ sign). I could specify the ‘!’ in its xml encoded unicode format such as requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,$#x0021;” or I could specify it in its unicode encoded form or in the “<,>,*,%,&,:,\,?,%u0021” format. The following settings can be applied at Root Web.Config level, App Web.config level, Folder level or within a location tag: <location path="some path here"> <system.web> <httpRuntime maxUrlLength="" maxQueryStringLength="" requestPathInvalidChars="" .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If any of the above settings fail request validation, an Http 400 “Bad Request” HttpException is thrown. These can be easily handled on the Application_Error handler on Global.asax.   Also, a new attribute in <httpRuntime /> called “relaxedUrlToFileSystemMapping” has been added with a default of false. <httpRuntime … relaxedUrlToFileSystemMapping="true|false" /> When the relaxedUrlToFileSystemMapping attribute is set to false inbound Urls still need to be valid NTFS file paths. For example Urls (sans query string) need to be less than 260 characters; no path segment within a Url can use old-style DOS device names (LPT1, COM1, etc…); Urls must be valid Windows file paths. A url like “http://digg.com/http://cnn.com” should work with this attribute set to true (of course a few characters will need to be unblocked by removing them from requestPathInvalidCharacters="" above). Managed configuration for non-NTFS-compliant Urls is determined from the first valid configuration path found when walking up the path segments of the Url. For example, if the request Url is "/foo/bar/baz/<blah>data</blah>", and there is a web.config in the "/foo/bar" directory, then the managed configuration for the request comes from merging the configuration hierarchy to include the web.config from "/foo/bar". The value of the public property HttpRequest.PhysicalPath is set to [physical file path of the application root] + "REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". For example, given a request Url like "/foo/bar/baz/<blah>data</blah>", where the application root is "/foo/bar" and the physical file path for that root is "c:\inetpub\wwwroot\foo\bar", then PhysicalPath would be "c:\inetpub\wwwroot\foo\bar\ REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". Carl Dacosta ASP.NET QA Team

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  • SSAS Compare: an intern’s journey

    - by Red Gate Software BI Tools Team
    About a month ago, David mentioned an intern working in the BI Tools Team. That intern happens to be me! In five weeks’ time, I’ll start my second year of Computer Science at the University of Cambridge and be a full-time student again, but for the past eight weeks, I’ve been living a completely different life. As Jon mentioned before, the teams here at Red Gate are small and everyone (including the interns!) is responsible for the product as a whole. I’ve attended planning sessions, UX tests, daily meetings, and everything else a full-time member of the team would; I had as much say in where we would go next with the product as anyone; I was able to see that what I was doing was an important part of the product from the feedback we got in the UX tests. All these things almost made me forget that this is just an internship and not my full-time job. First steps at Red Gate Being based in Cambridge, Red Gate has many Cambridge university graduates working for them. They also hire some Cambridge undergraduates for internships each summer. With its popularity with university graduates and its great working environment, Red Gate has managed to build up a great reputation. When I thought of doing an internship here in Cambridge, Red Gate just seemed to be the obvious choice for my first real work experience. On my first day at Red Gate, David, the lead developer for SSAS Compare, helped me settle in and explained what I’d be doing. My task was to improve the user experience of displaying differences between MDX scripts by syntax highlighting, script formatting, and improving the difference identification in the first place. David suggested how I should approach the problem, but left all the details and design decisions to me. That was when I realised how much independence and responsibility I’d have. What I’ve done If you launch the latest version of SSAS Compare and drill down to an MDX script difference, you can see the changes that have been made. In earlier versions, you could only see the scripts in plain text on both sides — either in black or grey, depending on whether they were the same or not. However, you couldn’t see exactly where the scripts were different, which was especially annoying when the two scripts were large – as they often are. Furthermore, if parts of the two scripts were formatted differently, they seemed to be different but were actually the same, which caused even more confusion and made it difficult to see where the differences were. All these issues have been fixed now. The two scripts are automatically formatted by the tool so that if two things are syntactically equivalent, they look the same – including case differences in keywords! The actual difference is highlighted in grey, which makes them easy to spot. The difference identification has been improved as well, so two scripts aren’t identified as different if there’s just a difference in meaningless whitespace characters, or when you have “select” on one side and “SELECT” on the other. We also have syntax highlighting, which makes it easier to read the scripts. How I did it In order to do the formatting properly, we decided to parse the MDX scripts. After some investigation into parser builders, I decided to go with the GOLD Parser builder and the bsn-goldparser .NET engine. GOLD Parser builder provides a fairly nice GUI to write, build, and test grammar in. We also liked the idea of separating the grammar building from parsing a text. The bsn-goldparser is one of many .NET engines for GOLD, and although it doesn’t support the newest features of GOLD Parser, it has “the ability to map semantic action classes to terminals or reduction rules, so that a completely functional semantic AST can be created directly without intermediate token AST representation, and without the need for glue code.” That makes it much easier for us to change the implementation in our program when we change the grammar. As bsn-goldparser is open source, and I wanted some more features in it, I contributed two new features which have now been merged to the project. Unfortunately, there wasn’t an MDX grammar written for GOLD already, so I had to write it myself. I was referencing MSDN to get the formal grammar specification, but the specification was all over the place, so it wasn’t that easy to implement and find. We’re aware that we don’t yet fully support all valid MDX, so sometimes you’ll just see the MDX script difference displayed the old way. In that case, there is some grammar construct we don’t yet recognise. If you come across something SSAS Compare doesn’t recognise, we’d love to hear about it so we can add it to our grammar. When some MDX script gets parsed, a tree is produced. That tree can then be processed into a list of inlines which deal with the correct formatting and can be outputted to the screen. Doing all this has led me to many new technologies and projects I haven’t worked with before. This was my first experience with C# and Visual Studio, although I have done things in Java before. I have learnt how to unit test with NUnit, how to do dependency injection with Ninject, how to source-control code with SVN and Mercurial, how to build with TeamCity, how to use GOLD, and many other things. What’s coming next Sadly, my internship comes to an end this week, so there will be less development on MDX difference view for a while. But the team is going to work on marking the differences better and making it consistent with difference indication in the top part of comparison window, and will keep adding support for more MDX grammar so you can see the differences easily in every comparison you make. So long! And maybe I’ll see you next summer!

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  • Tweaking a few URL validation settings on ASP.NET v4.0

    - by Carlyle Dacosta
    ASP.NET has a few default settings for URLs out of the box. These can be configured quite easily in the web.config file within the  <system.web>/<httpRuntime> configuration section. Some of these are: <httpRuntime maxUrlLength=”<number here>” This number should be an integer value (defaults to 260 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. This attribute gates the length of the Url without query string. <httpRuntime maxQueryStringLength=”<number here>”. This number should be an integer value (defaults to 2048 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. <httpRuntime requestPathInvalidCharacters=”List of characters you need included in ASP.NETs validation checks” /> By default the characters are “<,>,*,%,&,:,\,?”. However once can easily change this by setting by modifying web.config. Remember, these characters can be specified in a variety of formats. For example, I want the character ‘!’ to be included in ASP.NETs URL validation logic. So I set the following: <httpRuntime requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,!”. A character could also be specified in its xml encoded form. ‘&lt;;’ would mean the ‘<’ sign). I could specify the ‘!’ in its xml encoded unicode format such as requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,$#x0021;” or I could specify it in its unicode encoded form or in the “<,>,*,%,&,:,\,?,%u0021” format. The following settings can be applied at Root Web.Config level, App Web.config level, Folder level or within a location tag: <location path="some path here"> <system.web> <httpRuntime maxUrlLength="" maxQueryStringLength="" requestPathInvalidChars="" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If any of the above settings fail request validation, an Http 400 “Bad Request” HttpException is thrown. These can be easily handled on the Application_Error handler on Global.asax.   Also, a new attribute in <httpRuntime /> called “relaxedUrlToFileSystemMapping” has been added with a default of false. <httpRuntime … relaxedUrlToFileSystemMapping="true|false" /> When the relaxedUrlToFileSystemMapping attribute is set to false inbound Urls still need to be valid NTFS file paths. For example Urls (sans query string) need to be less than 260 characters; no path segment within a Url can use old-style DOS device names (LPT1, COM1, etc…); Urls must be valid Windows file paths. A url like “http://digg.com/http://cnn.com” should work with this attribute set to true (of course a few characters will need to be unblocked by removing them from requestPathInvalidCharacters="" above). Managed configuration for non-NTFS-compliant Urls is determined from the first valid configuration path found when walking up the path segments of the Url. For example, if the request Url is "/foo/bar/baz/<blah>data</blah>", and there is a web.config in the "/foo/bar" directory, then the managed configuration for the request comes from merging the configuration hierarchy to include the web.config from "/foo/bar". The value of the public property HttpRequest.PhysicalPath is set to [physical file path of the application root] + "REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". For example, given a request Url like "/foo/bar/baz/<blah>data</blah>", where the application root is "/foo/bar" and the physical file path for that root is "c:\inetpub\wwwroot\foo\bar", then PhysicalPath would be "c:\inetpub\wwwroot\foo\bar\ REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH".

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  • Parallelism in .NET – Part 8, PLINQ’s ForAll Method

    - by Reed
    Parallel LINQ extends LINQ to Objects, and is typically very similar.  However, as I previously discussed, there are some differences.  Although the standard way to handle simple Data Parellelism is via Parallel.ForEach, it’s possible to do the same thing via PLINQ. PLINQ adds a new method unavailable in standard LINQ which provides new functionality… LINQ is designed to provide a much simpler way of handling querying, including filtering, ordering, grouping, and many other benefits.  Reading the description in LINQ to Objects on MSDN, it becomes clear that the thinking behind LINQ deals with retrieval of data.  LINQ works by adding a functional programming style on top of .NET, allowing us to express filters in terms of predicate functions, for example. PLINQ is, generally, very similar.  Typically, when using PLINQ, we write declarative statements to filter a dataset or perform an aggregation.  However, PLINQ adds one new method, which provides a very different purpose: ForAll. The ForAll method is defined on ParallelEnumerable, and will work upon any ParallelQuery<T>.  Unlike the sequence operators in LINQ and PLINQ, ForAll is intended to cause side effects.  It does not filter a collection, but rather invokes an action on each element of the collection. At first glance, this seems like a bad idea.  For example, Eric Lippert clearly explained two philosophical objections to providing an IEnumerable<T>.ForEach extension method, one of which still applies when parallelized.  The sole purpose of this method is to cause side effects, and as such, I agree that the ForAll method “violates the functional programming principles that all the other sequence operators are based upon”, in exactly the same manner an IEnumerable<T>.ForEach extension method would violate these principles.  Eric Lippert’s second reason for disliking a ForEach extension method does not necessarily apply to ForAll – replacing ForAll with a call to Parallel.ForEach has the same closure semantics, so there is no loss there. Although ForAll may have philosophical issues, there is a pragmatic reason to include this method.  Without ForAll, we would take a fairly serious performance hit in many situations.  Often, we need to perform some filtering or grouping, then perform an action using the results of our filter.  Using a standard foreach statement to perform our action would avoid this philosophical issue: // Filter our collection var filteredItems = collection.AsParallel().Where( i => i.SomePredicate() ); // Now perform an action foreach (var item in filteredItems) { // These will now run serially item.DoSomething(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This would cause a loss in performance, since we lose any parallelism in place, and cause all of our actions to be run serially. We could easily use a Parallel.ForEach instead, which adds parallelism to the actions: // Filter our collection var filteredItems = collection.AsParallel().Where( i => i.SomePredicate() ); // Now perform an action once the filter completes Parallel.ForEach(filteredItems, item => { // These will now run in parallel item.DoSomething(); }); This is a noticeable improvement, since both our filtering and our actions run parallelized.  However, there is still a large bottleneck in place here.  The problem lies with my comment “perform an action once the filter completes”.  Here, we’re parallelizing the filter, then collecting all of the results, blocking until the filter completes.  Once the filtering of every element is completed, we then repartition the results of the filter, reschedule into multiple threads, and perform the action on each element.  By moving this into two separate statements, we potentially double our parallelization overhead, since we’re forcing the work to be partitioned and scheduled twice as many times. This is where the pragmatism comes into play.  By violating our functional principles, we gain the ability to avoid the overhead and cost of rescheduling the work: // Perform an action on the results of our filter collection .AsParallel() .Where( i => i.SomePredicate() ) .ForAll( i => i.DoSomething() ); The ability to avoid the scheduling overhead is a compelling reason to use ForAll.  This really goes back to one of the key points I discussed in data parallelism: Partition your problem in a way to place the most work possible into each task.  Here, this means leaving the statement attached to the expression, even though it causes side effects and is not standard usage for LINQ. This leads to my one guideline for using ForAll: The ForAll extension method should only be used to process the results of a parallel query, as returned by a PLINQ expression. Any other usage scenario should use Parallel.ForEach, instead.

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  • Windows Phone 7 development: first impressions

    - by DigiMortal
    After hard week in work I got some free time to play with Windows Phone 7 CTP developer tools. Although my first test application is still unfinished I think it is good moment to share my first experiences to you. In this posting I will give you quick overview of Windows Phone 7 developer tools from developer perspective. If you are familiar with Visual Studio 2010 then you will feel comfortable because Windows Phone 7 CTP developer tools base on Visual Studio 2010 Express. Project templates There are five project templates available. Three of them are based on Silverlight and two on XNA Game Studio: Windows Phone Application (Silverlight) Windows Phone List Application (Silverlight) Windows Phone Class Library (Silverlight) Windows Phone Game (XNA Game Studio) Windows Phone Game Library (XNA Game Studio) Currently I am writing to test applications. One of them is based on Windows Phone Application and the other on Windows Phone List Application project template. After creating these projects you see the following views in Visual Studio. Windows Phone Application. Click on image to enlarge. Windows Phone List Application. Click on image to enlarge.  I suggest you to use some of these templates to get started more easily. Windows Phone 7 emulator You can run your Windows Phone 7 applications on Windows Phone 7 emulator that comes with developer tools CTP. If you run your application then emulator is started automatically and you can try out how your application works in phone-like emulator. You can see screenshot of emulator on right. Currently there is opened Windows Phone List Application as it is created by default. Click on image to enlarge it. Emulator is a little bit slow and uncomfortable but it works pretty well. This far I have caused only couple of crashes during my experiments. In these cases emulator works but Visual Studio gets stuck because it cannot communicate with emulator. One important note. Emulator is based on virtual machine although you can see only phone screen and options toolbar. If you want to run emulator you must close all virtual machines running on your machine and run Visual Studio 2010 as administrator. Once you run emulator you can keep it open because you can stop your application in Visual Studio, modify, compile and re-deploy it without restarting emulator. Designing user interfaces You can design user interface of your application in Visual Studio. When you open XAML-files it is displayed in window with two panels. Left panel shows you device screen and works as visual design environment while right panel shows you XAML mark-up and let’s you modify XML if you need it. As it is one of my very first Silverlight applications I felt more comfortable with XAML editor because property names in property boxes of visual designer confused me a little bit. Designer panel is not very good because it is visually hard to follow. It has black background that makes dark borders of controls very hard to see. If you have monitor with very high contrast then it is may be not a real problem. I have usual monitor and I have problem. :) Putting controls on design surface, dragging and resizing them is also pretty painful. Some controls are drawn correctly but for some controls you have to set width and height in XML so they can be resized. After some practicing it is not so annoying anymore. On the right you can see toolbox with some controllers. This is all you get out of the box. But it is sufficient to get started. After getting some experiences you can create your own controls or use existing ones from other vendors or developers. If it is your first time to do stuff with Silverlight then keep Google open – you need it hard. After getting over the first shock you get the point very quickly and start developing at normal speed. :) Writing source code Writing source code is the most familiar part of this action. Good old Visual Studio code editor with all nice features it has. But here you get also some surprises: The anatomy of Silverlight controls is a little bit different than the one of user controls in web and forms projects. Windows Phone 7 doesn’t run on full version of Windows (I bet it is some version of Windows CE or something like this) then there is less system classes you can use. Some familiar classes have less methods that in full version of .NET Framework and in these cases you have to write all the code by yourself or find libraries or source code from somewhere. These problems are really not so much problems than limitations and you get easily over them. Conclusion Windows Phone 7 CTP developer tools help you do a lot of things on Windows Phone 7. Although I expected better performance from tools I think that current performance is not a problem. This far my first test project is going very well and Google has answer for almost every question. Windows Phone 7 is mobile device and therefore it has less hardware resources than desktop computers. This is why toolset is so limited. The more you need memory the more slower is device and as you may guess it needs the more battery. If you are writing apps for mobile devices then make your best to get your application use as few resources as possible and act as fast as possible.

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  • Parallelism in .NET – Part 17, Think Continuations, not Callbacks

    - by Reed
    In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

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