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  • What characteristic of networking/TCP causes linear relation between TCP activity and latency?

    - by DeLongey
    The core of this problem is that our application uses websockets for real-time interfaces. We are testing our app in a new environment but strangely we're noticing an increasing delay in TCP websocket packets associated with an increase in websocket activity. For example, if one websocket event occurs without any other activity in a 1-minute period, the response from the server is instantaneous. However, if we slowly increase client activity the latency in server response increases with a linear relationship (each packet will take more time to reach the client with more activity). For those wondering this is NOT app-related since our logs show that our server is running and responding to requests in under 100ms as desired. The delay starts once the server processes the request and creates the TCP packet and sends it to the client (and not the other way around). Architecture This new environment runs with a Virtual IP address and uses keepalived on a load balancer to balance the traffic between instances. Two boxes sit behind the balancer and all traffic runs through it. Our host provider manages the balancer and we do not have control over that part of the architecture. Theory Could this somehow be related to something buffering the packets in the new environment? Thanks for your help.

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  • C++ OpenSource project for beginner programmer?

    - by VeminZ
    I`m a beginner C++ programmer. And I want to pursue my career in system- and driver-programming. Can you suggest me an opensource projects to I improve my skills in low-level development? I am looking for a project with the following characteristic: - on C\C++ language based - a small project with a small amount of code, yet - UNIX-based systems designed Do you know that something like this?

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  • Receiving data with Winsock

    - by Tamir
    Right now, I'm programming the networking for my online game, and I'm not really sure what to do about receiving data. The problem is that I can't really guess the packet's size, so I thought of reading just 4 bytes from the packet and converting them to an int to know what's the packet's size. Then I'll just create a buffer in that size and receive the rest of the packet, is that a good idea? For your information, I'm using non-blocking i/o.

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  • Communicating with a MW-3170 magnetic card reader

    - by stukelly
    One of our customers has asked if we can interface with a serial magnetic card reader/encoder from a old EPOS system. The device has no make only the MW-3170 model number. Does anybody know how I can communicate with the device? I am currently looking for a programming manual on Google, without much success.

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  • .Net Library for parsing source code files?

    - by Jörg Battermann
    Does anyone know of a good .NET library that allows me to parse source code files, but not only .NET source code files (like java, perl, ruby, etc)? I need programmatic access to the contents of various source code files (e.g. class/method /parameter names, types, etc.). Has anyone come across something like this? I know within .NET it is reasonably possible and there are some libraries out there, but I need that to be abstracted to more types of programming languages.

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  • could I know which file is altered using fsevent?

    - by Frost Li
    I get the directory path from fsevent, such as "/User/Data/" But what I really want is "/User/Data/change.txt" I have read the programming guide, it said typedef void ( *FSEventStreamCallback )( ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]); eventPaths An array of paths to the directories in which event(s) occurred. is there any method to find out which file is altered? thanks!!!! I have stuck to it for so long..

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  • Error compiling Win32 API GUI code with MinGW

    - by Eric Larsen
    Hey guys, this is my first post. I'm just getting started with win32 API programming in C++ and I'm having trouble compiling the winnie tutorial (http://www.relisoft.com/win32/winnie.html) with MinGW. My input and output: C:\Users\Eric\Projects g++ winnie.cpp -o winnie.exe /mingw/lib/libmingw32.a(main.o):main.c:(.text+0xd2): undefined reference to 'WinMain@16' collect2: ld returned 1 exit status Any help would be very much appreciated.

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  • Porting Windows socket program to Unix: Alternative for winsock32 APIs in unix

    - by Amita
    In Socket Programming, how will a Unix thread receive a Socket CLOSE event from a client if connection is closed? Are there any API's which will notify the unix thread about the CLOSE event received? As in Windows we have WSAEnumNetworkEvents API which gets the event notification for a specified socket descriptor. What will be the equivalent API used in the Unix socket programing? Please provide the help for the query.

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  • SharePoint Search Center issue

    - by George2
    Hello everyone, I am using SharePoint Server 2007 with collaboration portal template on Windows Server 2008. The default search address for a site is pointed to /SearchCenter/Pages/Results.aspx. Any ideas how to change the address to some other address? Either programming solution or easy config solution is fine. thanks in advance, George

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  • Why would Windows use slower network interface despite route metrics?

    - by tim11g
    On my previous notebook, the Dell/Broadcom wireless adapter had an option to automatically disable wireless when a wired network is connected, so I never dealt with multiple active interfaces. My current system has an Intel wireless adapter, and they apparently haven't figured out how to turn it off when there is a wired connection. Unless I explicitly remember to disable wireless when docked, the connection is active. That shouldn't be a problem (in theory), since the route metric will cause traffic to go over the fastest network (as indicated by the lowest metric in the routing table). Apparently not - I'm running a backup and seeing the throughput at 25Mbps or so (which is consistent with 802.11g) when a perfectly good Gigabit Ethernet interface is also connected. IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.1.254 192.168.1.104 10 0.0.0.0 0.0.0.0 192.168.1.254 192.168.1.109 25 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 Windows has correctly identified the Ethernet interface (.104) and assigned it the lower (preferred) metric. So the Ethernet interface should be used exclusively, right? Why is the Ethernet connection not being used? What other factors are involved? (This is with Windows 7 if it makes a difference)

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  • Create XML File Using XML Schema

    - by metdos
    Is there any easy way to create at least a template XML file using XML Schema? My main interest is bounded by C++, but discussions of other programming languages are also welcome.By the way I also use QT framework.

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  • HTTP Request from a PC to load the contents of a wap site

    - by cocoatoucher
    When I try to load a wap site with PHP HTTP request from my PC, host of the web site recognizes that I'm sending the request from a PC and redirects me to their actual web site and I can't load the wap site. Is there a way to behave like a mobile browser and prevent this redirection? Although an answer regarding any programming language is ok, a php specific answer will be better.

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  • Single Sign On-- SSO

    - by James
    Please I would like someone to tell me if dotNetOpenAuth single-sign-on. All I want to achieve is to be able to seamlessly logging to all domains without redirect to third party system for authorisation or Authentication within a mixture programming platforms e.g (PHP or .Net)

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  • sql server 2008 cluster hang when a heavy load is run

    - by Billy OT
    we have a sql server 2008 active/active cluster running on wondows 2008R2 O/S. 14GB RAM, 4xCPU. we have set a ceiling of 12GB for sql server. We're running an agent job which loads 3 million records to a database. during this load the job fails and the cluster seems to attempt to fail over to the other node but unsuccessfully i.e., the cluster address is no longer accessible. we have to manually fail the cluster node back. during the load on viewing task manager we can see that memory usage hits a max of 12.5GB and CPU at times hits 100% on all 4 CPU, but for the most part fluctuates at an average of about 60%. I suppose my question is, will a cluster try to fail over if memory or CPU are taking a heavy hit? or am i barking up the wrong tree? also any ideas why it wouldn't fully fail over? we've crawled through logs, of which there are a lot, and can't find anything useful. we've also tried recreating the issue but it ran successfully at a later time. Also 3 million rows doesn't seem like a lot but in terms of resources should 14GB RAM and 4xCPU not be sufficient? Further information on this, we ran the load again today and corrupted the database! We received the error message : LogWriter: Operating system error 170. It looks like, under the heavy load, the sql cluster attempted to fail over and in doing so migrated a lun (or drive) which meant the disk was no longer reachable. (this is just our theory). The database is now 'suspect' and requiring restoration. The 170 error above also indicates that on failing over to the other node, the sql service could not start as it was already in use, therefore it couldn't fail over fully?? But I'm wondering why would it need to fail over in the first place? My assumptions could be completely wrong on this, so any ideas would be appreciated.

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  • Xml parsing in Objective c

    - by Raju
    NSString *myxml=@"<students> <student><name>Raju</name><age>25</age><address>abcd</address> </student></students>"; in iPhone programming how to parse this XML by each node. ....

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  • Dual boot nt4 and windows 98

    - by ItFinallyWorks
    I am trying to dual boot nt4 and windows 98 se (don't laugh - old computer). I have seen Microsoft's instructions for doing this, but it limits windows 98 to have a Fat16 partition (NT4's NTLDR doesn't understand FAT32) and therefore only 2GB of disk space. I really need it to have more than that. I started with Win 98 (on the 1st partition), repartitioned the disk, then added NT4 on the 2nd partition. NT4 took over the bootloader (as expected), so NT4 boots, but Win 98 doesn't. Right now I am working in VMWare so I can use nonpersistent hard drives (IDE like the real computer) to recover from errors easily. I've tried using XPs NTLDR using the instructions here: http://www.nu2.nu/fixnt4/ , but I got weird errors from NT4 and it never really worked. If XP's NTLDR would work, that should be able to boot both OSes. I've also tried using GRUB. In theory that should work. In fact when booting from super grub disk, it does. But as soon as I install grub to disk, Win 98 boots, but NT 4 blue screens at boot with a 0x0000007b inaccessible_boot_device error (that can be alot of things see MS kb 822051). The incantation I'm using for GRUB 1 is rootnoverify (hd0,1) makeactive chainloader +1 boot So, anybody have some suggestions?

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  • Does oneway declaration in Android .aidl guarantee that method will be called in a separate thread?

    - by Dan Menes
    I am designing a framework for a client/server application for Android phones. I am fairly new to both Java and Android (but not new to programming in general, or threaded programming in particular). Sometimes my server and client will be in the same process, and sometimes they will be in different processes, depending on the exact use case. The client and server interfaces look something like the following: IServer.aidl: package com.my.application; interface IServer { /** * Register client callback object */ void registerCallback( in IClient callbackObject ); /** * Do something and report back */ void doSomething( in String what ); . . . } IClient.aidl: package com.my.application; oneway interface IClient { /** * Receive an answer */ void reportBack( in String answer ); . . . } Now here is where it gets interesting. I can foresee use cases where the client calls IServer.doSomething(), which in turn calls IClient.reportBack(), and on the basis of what is reported back, IClient.reportBack() needs to issue another call to IClient.doSomething(). The issue here is that IServer.doSomething() will not, in general, be reentrant. That's OK, as long as IClient.reportBack() is always invoked in a new thread. In that case, I can make sure that the implementation of IServer.doSomething() is always synchronized appropriately so that the call from the new thread blocks until the first call returns. If everything works the way I think it does, then by declaring the IClient interface as oneway, I guarantee this to be the case. At least, I can't think of any way that the call from IServer.doSomething() to IClient.reportBack() can return immediately (what oneway is supposed to ensure), yet IClient.reportBack still be able to reinvoke IServer.doSomething recursively in the same thread. Either a new thread in IServer must be started, or else the old IServer thread can be re-used for the inner call to IServer.doSomething(), but only after the outer call to IServer.doSomething() has returned. So my question is, does everything work the way I think it does? The Android documentation hardly mentions oneway interfaces.

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  • ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

    - by Imran
    Can someone please help as i've spent all day trying to fix this. I installed the latest XAMPP and now i can't connect to mysql from terminal.I checked my .profile file and the PATH seems ok. Does anyone know whats happened and what's the solution? PATH=$PATH:/Applications/XAMPP/xamppfiles/bin export PATH THIS IS A PROGRAMMING QUESTION AS I'M A PHP DEVELOPER TRYING TO DO MY JOB! Thankyou soo much in advance;-)

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  • Help Understanding the Mork File Format

    - by Sumit Ghosh
    Hi, I have a name value pair in a Java HashMap and this in continuation to my earlier question - here NickName=,LastModifiedDate=4ac18267,FaxNumberType=,BirthMonth=,LastName=,HomePhone=,WorkCountry=,HomePhoneType=,PreferMailFormat=0,CellularNumber=,FamilyName=,[email protected],AnniversaryMonth=,HomeCity=,WorkState=,HomeCountry=,PhoneticFirstName=,PhoneticLastName=,HomeState=,WorkAddress=,WebPage1=,WebPage2=,HomeAddress2=,WorkZipCode=,_AimScreenName=,AnniversaryYear=,WorkPhoneType=,Notes=,WorkAddress2=,WorkPhone=,Custom3=,Custom4=,Custom1=,Custom2=,PagerNumber=,AnniversaryDay=,WorkCity=,AllowRemoteContent=0,CellularNumberType=,FaxNumber=,PopularityIndex=2,FirstName=,SpouseName=,CardType=,Department=,Company=,HomeAddress=,BirthDay=,SecondEmail=,RecordKey=1,DisplayName=,DefaultEmail=,DefaultAddress=,BirthYear=,Category=,PagerNumberType=,[email protected],JobTitle=,HomeZipCode=, NickName=,LastModifiedDate=0,FaxNumberType=,BirthMonth=,LastName=Ghosh,HomePhone=+504-9907-1342,WorkCountry=USA,HomePhoneType=,PreferMailFormat=2,CellularNumber=512-282-2512,FamilyName=,[email protected],AnniversaryMonth=,HomeCity=Siguatepeque,WorkState=TX,HomeCountry=Honduras,PhoneticFirstName=,PhoneticLastName=,HomeState=Comayagua,WorkAddress=9309 HeatherwoodDr,WebPage1=http://www.mpcsol.com,WebPage2=http://www.jesuslovesthelittlechildren.org,HomeAddress2=VillaAlicia,WorkZipCode=78748,_AimScreenName=rentaprogrammer,AnniversaryYear=,WorkPhoneType=,Notes=Some notes go here.,WorkAddress2=Apartment 1,WorkPhone=512-282-2509,Custom3=Faith,Custom4=Timothy,Custom1=Hannah,Custom2=John,PagerNumber=512-282-2511,AnniversaryDay=,WorkCity=Austin,AllowRemoteContent=1,CellularNumberType=,FaxNumber=512-282-2510,PopularityIndex=0,FirstName=Sumit,SpouseName=,CardType=,Department=Programming,Company=MPC Solutions,HomeAddress=Two Blocks Past Oxen Team,BirthDay=,[email protected],RecordKey=2,DisplayName=Sumit,DefaultEmail=,DefaultAddress=,BirthYear=,Category=,PagerNumberType=,[email protected],JobTitle=Programmer,HomeZipCode=NA, NickName=,LastModifiedDate=0,FaxNumberType=,BirthMonth=,LastName=,HomePhone=,WorkCountry=,HomePhoneType=,PreferMailFormat=0,CellularNumber=,FamilyName=,[email protected],AnniversaryMonth=,HomeCity=,WorkState=,HomeCountry=,PhoneticFirstName=,PhoneticLastName=,HomeState=,WorkAddress=,WebPage1=,WebPage2=,HomeAddress2=,WorkZipCode=,_AimScreenName=,AnniversaryYear=,WorkPhoneType=,Notes=,WorkAddress2=,WorkPhone=,Custom3=,Custom4=,Custom1=,Custom2=,PagerNumber=,AnniversaryDay=,WorkCity=,AllowRemoteContent=0,CellularNumberType=,FaxNumber=,PopularityIndex=0,FirstName=,SpouseName=,CardType=,Department=,Company=,HomeAddress=,BirthDay=,SecondEmail=,RecordKey=3,DisplayName=,DefaultEmail=,DefaultAddress=,BirthYear=,Category=,PagerNumberType=,[email protected],JobTitle=,HomeZipCode=, I want to write it to a Mork file , using the Mork file format, can someone tell me how to decode the name value pair to this format given below. <(A9=3)(81=)([email protected])(80=0)(85=2)(86=4ac18267)(83=1) (87=Sumit)(88=Ghosh)(89=Sumit)([email protected])(8B [email protected])(8C=512-282-2509)(8D=+504-9907-1342)(8E=512-282-2510) (8F=512-282-2511)(90=512-282-2512)(91=Two Blocks Past Oxen Team)(92 =Villa Alicia)(93=Siguatepeque)(94=Comayagua)(95=NA)(96=Honduras) (97=9309 Heatherwood Dr)(98=Apartment 1)(99=Austin)(9A=TX)(9B=78748) (9C=USA)(9D=Programmer)(9E=Programming)(9F=MPC Solutions)(A0 =rentaprogrammer)(A1=http://www.mpcsol.com)(A2 =http://www.jesuslovesthelittlechildren.org)(A3=Hannah)(A4=John) (A5=Faith)(A6=Timothy)(A7=Some notes go here.)(A8 [email protected])> {1:^80 {(k^C0:c)(s=9)} [1:^82(^BF=3)] [1(^83=)(^84=)(^85=)(^86=)(^87=)(^88=)(^89^82)(^8A^82)(^8B=)(^8C=) (^8D=)(^8E=0)(^8F=2)(^90=0)(^91=)(^92=)(^93=)(^94=)(^95=)(^96=) (^97=)(^98=)(^99=)(^9A=)(^9B=)(^9C=)(^9D=)(^9E=)(^9F=)(^A0=)(^A1=) (^A2=)(^A3=)(^A4=)(^A5=)(^A6=)(^A7=)(^A8=)(^A9=)(^AA=)(^AB=)(^AC=) (^AD=)(^AE=)(^AF=)(^B0=)(^B1=)(^B2=)(^B3=)(^B4=)(^B5=)(^B6=)(^B7=) (^B8=)(^B9=)(^BA=)(^BB=)(^BC^86)(^BD=1)] [2(^83^87)(^84^88)(^85=)(^86=)(^87^89)(^88=)(^89^8A)(^8A^8A)(^8B^8B) (^8C=)(^8D=)(^8E=2)(^8F=0)(^90=1)(^91^8C)(^92^8D)(^93^8E)(^94^8F) (^95^90)(^96=)(^97=)(^98=)(^99=)(^9A=)(^9B^91)(^9C^92)(^9D^93)(^9E^94) (^9F=NA)(^A0^96)(^A1^97)(^A2^98)(^A3^99)(^A4=TX)(^A5^9B)(^A6^9C) (^A7^9D)(^A8^9E)(^A9^9F)(^AA^A0)(^AB=)(^AC=)(^AD=)(^AE=)(^AF=)(^B0=) (^B1=)(^B2^A1)(^B3^A2)(^B4=)(^B5=)(^B6=)(^B7^A3)(^B8^A4)(^B9^A5) (^BA^A6)(^BB^A7)(^BC=0)(^BD=2)] [3(^83=)(^84=)(^85=)(^86=)(^87=)(^88=)(^89^A8)(^8A^A8)(^8B=)(^8C=) (^8D=)(^8E=0)(^8F=0)(^90=0)(^91=)(^92=)(^93=)(^94=)(^95=)(^96=) (^97=)(^98=)(^99=)(^9A=)(^9B=)(^9C=)(^9D=)(^9E=)(^9F=)(^A0=)(^A1=) (^A2=)(^A3=)(^A4=)(^A5=)(^A6=)(^A7=)(^A8=)(^A9=)(^AA=)(^AB=)(^AC=) (^AD=)(^AE=)(^AF=)(^B0=)(^B1=)(^B2=)(^B3=)(^B4=)(^B5=)(^B6=)(^B7=) (^B8=)(^B9=)(^BA=)(^BB=)(^BC=0)(^BD=3)]}

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  • Will disabling hyperthreading improve performance on our SQL Server install

    - by Sam Saffron
    Related to: Current wisdom on SQL Server and Hyperthreading Recently we upgraded our Windows 2008 R2 database server from an X5470 to a X5560. The theory is both CPUs have very similar performance, if anything the X5560 is slightly faster. However, SQL Server 2008 R2 performance has been pretty bad over the last day or so and CPU usage has been pretty high. Page life expectancy is massive, we are getting almost 100% cache hit for the pages, so memory is not a problem. When I ran: SELECT * FROM sys.dm_os_wait_stats order by signal_wait_time_ms desc I got: wait_type waiting_tasks_count wait_time_ms max_wait_time_ms signal_wait_time_ms ------------------------------------------------------------ -------------------- -------------------- -------------------- -------------------- XE_TIMER_EVENT 115166 2799125790 30165 2799125065 REQUEST_FOR_DEADLOCK_SEARCH 559393 2799053973 5180 2799053973 SOS_SCHEDULER_YIELD 152289883 189948844 960 189756877 CXPACKET 234638389 2383701040 141334 118796827 SLEEP_TASK 170743505 1525669557 1406 76485386 LATCH_EX 97301008 810738519 1107 55093884 LOGMGR_QUEUE 16525384 2798527632 20751319 4083713 WRITELOG 16850119 18328365 1193 2367880 PAGELATCH_EX 13254618 8524515 11263 1670113 ASYNC_NETWORK_IO 23954146 6981220 7110 1475699 (10 row(s) affected) I also ran -- Isolate top waits for server instance since last restart or statistics clear WITH Waits AS ( SELECT wait_type, wait_time_ms / 1000. AS [wait_time_s], 100. * wait_time_ms / SUM(wait_time_ms) OVER() AS [pct], ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS [rn] FROM sys.dm_os_wait_stats WHERE wait_type NOT IN ('CLR_SEMAPHORE','LAZYWRITER_SLEEP','RESOURCE_QUEUE', 'SLEEP_TASK','SLEEP_SYSTEMTASK','SQLTRACE_BUFFER_FLUSH','WAITFOR','LOGMGR_QUEUE', 'CHECKPOINT_QUEUE','REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT','BROKER_TO_FLUSH', 'BROKER_TASK_STOP','CLR_MANUAL_EVENT','CLR_AUTO_EVENT','DISPATCHER_QUEUE_SEMAPHORE', 'FT_IFTS_SCHEDULER_IDLE_WAIT','XE_DISPATCHER_WAIT', 'XE_DISPATCHER_JOIN')) SELECT W1.wait_type, CAST(W1.wait_time_s AS DECIMAL(12, 2)) AS wait_time_s, CAST(W1.pct AS DECIMAL(12, 2)) AS pct, CAST(SUM(W2.pct) AS DECIMAL(12, 2)) AS running_pct FROM Waits AS W1 INNER JOIN Waits AS W2 ON W2.rn <= W1.rn GROUP BY W1.rn, W1.wait_type, W1.wait_time_s, W1.pct HAVING SUM(W2.pct) - W1.pct < 95; -- percentage threshold And got wait_type wait_time_s pct running_pct CXPACKET 554821.66 65.82 65.82 LATCH_EX 184123.16 21.84 87.66 SOS_SCHEDULER_YIELD 37541.17 4.45 92.11 PAGEIOLATCH_SH 19018.53 2.26 94.37 FT_IFTSHC_MUTEX 14306.05 1.70 96.07 That shows huge amounts of time synchronizing queries involving parallelism (high CXPACKET). Additionally, anecdotally many of these problem queries are being executed on multiple cores (we have no MAXDOP hints anywhere in our code) The server has not been under load for more than a day or so. We are experiencing a large amount of variance with query executions, typically many queries appear to be slower that they were on our previous DB server and CPU is really high. Will disabling Hyperthreading help at reducing our CPU usage and increase throughput?

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  • Parallel port recording to file on Win XP

    - by Nikola Kotur
    Hi there. I need to write a simple program that records all the input from parallel port into a file. Data flows from industrial machine, setup is fairly simple, but I can't find any good open source examples on parallel port reading for Windows. Do you know a software that does this (and lets me learn how to do it myself), or is there any guideline for parallel port programming on XP? Thanks.

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  • Trouble with inheritance

    - by Matt
    I'm relatively new to programming so excuse me if I get some terms wrong (I've learned the concepts, I just haven't actually used most of them). Trouble: I currently have a class I'll call Bob its parent class is Cody, Cody has method call Foo(). I want Bob to have the Foo() method as well, except with a few extra lines of code. I've attempted to do Foo() : base(), however that doesn't seem to work like. Is there some simple solution to this?

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