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• Openfire and LDAP issues

  - by clsmith

  Thanks in advance for the help. Has anyone see this issue with openfire? Currently I use Openfire Fedora with Auth using windows 2003 and also use mysql for the database. When I bring up two clients and talk to each other the time is slow between messages. Sometimes it can take between 5-15 minutes for something sent to get to the person (this is with only two people on the openfire server). I ran a tcp dump using port 389 and see that the machine is running thousands of queries against ldap. When i plug it into wireshark I notice that it is transferring the entire contact list or checking on the status of the entire contact list ? When I run debug on openfire itself I am presented with only this small message in the log: 2010.06.08 07:01:17 LdapManager: Starting LDAP search... 2010.06.08 07:01:17 LdapManager: ... search finished 2010.06.08 07:01:17 LdapManager: Creating a DirContext in LdapManager.getContext()... 2010.06.08 07:01:17 LdapManager: Created hashtable with context values, attempting to create context... 2010.06.08 07:01:17 LdapManager: ... context created successfully, returning. 2010.06.08 07:01:17 LdapManager: Trying to find a groups's DN based on it's groupname. cn: Spark agents CLT, Base DN: OU="Hidden",DC="Hidden",DC="net"... 2010.06.08 07:01:17 LdapManager: Creating a DirContext in LdapManager.getContext()... 2010.06.08 07:01:17 LdapManager: Created hashtable with context values, attempting to create context... 2010.06.08 07:01:17 LdapManager: ... context created successfully, returning. 2010.06.08 07:01:17 LdapManager: Starting LDAP search... 2010.06.08 07:01:17 LdapManager: ... search finished 2010.06.08 07:01:17 LdapManager: Trying to find a groups's DN based on it's groupname. cn: Spark agents CLT, Base DN: OU="Hidden",DC="Hidden",DC="net"... 2010.06.08 07:01:17 LdapManager: Creating a DirContext in LdapManager.getContext()... 2010.06.08 07:01:17 LdapManager: Created hashtable with context values, attempting to create context... 2010.06.08 07:01:17 LdapManager: ... context created successfully, returning. 2010.06.08 07:01:17 LdapManager: Starting LDAP search... 2010.06.08 07:01:17 LdapManager: ... search finished I thought this was a configuration on my end and started to look into the cache settings on the openfire webpages. I tweaked the settings as recommend by the pages and still get the same issues. I doesnt seem to cache the contact list or this might be a feature never fixed or implemented. Has anyone gone through this before ? I have searched online and I see others have great experience with openfire with no issues like I have, or is it because noone checked the queries ? For the time being I created a new Domain Controller and moved openfire to that computer so it can run local queries. This seems to help reduce the speed alot, but when I run the server performance manager tool I see that with two people only using that openfire server I run 593.7 request per second. Thanks for your help, if I didnt provide enough data please let me know what you need and I can find it.

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• How to convert a 32bpp image to an indexed format?

  - by Ed Swangren

  So here are the details (I am using C# BTW): I receive a 32bpp image (JPEG compressed) from a server. At some point, I would like to use the Palette property of a bitmap to color over-saturated pixels (brightness 240) red. To do so, I need to get the image into an indexed format. I have tried converting the image to a GIF, but I get quality loss. I have tried creating a new bitmap in an index format by these methods: // causes a "Parameter not valid" error Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Indexed) // no error, but the resulting image is black due to information loss I assume Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Format8bppIndexed) I am at a loss now. The data in this image is changed constantly by the user, so I don't want to manually set pixels that have a brightness 240 if I can avoid it. If I can set the palette once when the image is created, my work is done. If I am going about this the wrong way to begin with please let me know. EDIT: Thanks guys, here is some more detail on what I am attempting to accomplish. We are scanning a tissue slide at high resolution (pathology application). I write the interface to the actual scanner. We use a line-scan camera. To test the line rate of the camera, the user scans a very small portion and looks at the image. The image is displayed next to a track bar. When the user moves the track bar (adjusting line rate), I change the overall intensity of the image in an attempt to model what it would look like at the new line rate. I do this using an ImageAttributes and ColorMatrix object currently. When the user adjusts the track bar, I adjust the matrix. This does not give me per pixel information, but the performance is very nice. I could use LockBits and some unsafe code here, but I would rather not rewrite it if possible. When the new image is created, I would like for all pixels with a brightness value of 240 to be colored red. I was thinking that defining a palette for the bitmap up front would be a clean way of doing this.

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• How to make freelance clients understand the costs of developing and maintaining mature products?

  - by John

  I have a freelance web application project where the client requests new features every two weeks or so. I am unable to anticipate the requirements of upcoming features. So when the client requests a new feature, one of several things may happen: I implement the feature with ease because it is compatible with the existing platform I implement the feature with difficulty because I have to rewrite a significant portion of the platform's foundation Client withdraws request because it costs too much to implement against existing platform At the beginning of the project, for about six months, all feature requests fell under category 1) because the system was small and agile. But for the past six months, most feature implementation fell under category 2). The system is mature, forcing me to refactor and test everytime I want to add new modules. Additionally, I find myself breaking things that use to work, and fixing it (I don't get paid for this). The client is starting to express frustration at the time and cost for me to implement new features. To them, many of the feature requests are of the same scale as the features they requested six months ago. For example, a client would ask, "If it took you 1 week to build a ticketing system last year, why does it take you 1 month to build an event registration system today? An event registration system is much simpler than a ticketing system. It should only take you 1 week!" Because of this scenario, I fear feature requests will soon land in category 3). In fact, I'm already eating a lot of the cost myself because I volunteer many hours to support the project. The client is often shocked when I tell him honestly the time it takes to do something. The client always compares my estimates against the early months of a project. I don't think they're prepared for what it really costs to develop, maintain and support a mature web application. When working on a salary for a full time company, managers were more receptive of my estimates and even encouraged me to pad my numbers to prepare for the unexpected. Is there a way to condition my clients to think the same way? Can anyone offer advice on how I can continue to work on this web project without eating too much of the cost myself? Additional info - I've only been freelancing full time for 1 year. I don't yet have the high end clients, but I'm slowly getting there. I'm getting better quality clients as time goes by.

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• set equal height on multiple divs

  - by Greenie

  I need to set equal height on a series of divs inside another div wrapper. The problem is that I dont want the same height on all of them. The page kind of have 3 columns and the floating divs can be 1, 2 or 3 columns wide. The divs float left, so the following example will give me three rows of divs in my wrapper. How can I set equal height on the divs that are in the same row? In my example I want nr 1 and 2 to have equal height and 3, 4 and 5 another equal height? I cant know beforehand how many divs there is or how wide or high they are. Edit: They can be for instance 300, 600 or 900 px wide and the page width is 900px <div id="wrapper"> <div class="one-wide">nr1</div> <div class="two-wide">nr2</div> <div class="one-wide">nr3</div> <div class="one-wide">nr4</div> <div class="one-wide">nr5</div> <div class="three-wide">nr6</div> </div> Im thinking I somehow need to figure out when the added width of the divs is at the full page width and set equal height on those. Then do the same on the next divs. But I cant wrap my head around it. Currently im just using this to set the height on the children of the wrapper: $.fn.equalHeights = function(px) { $(this).each(function(){ var currentTallest = 0; $(this).children().each(function(i){ if ($(this).height() > currentTallest) { currentTallest = $(this).height(); } }); // for ie6, set height since min-height isn't supported if ($.browser.msie && $.browser.version == 6.0) { $(this).children().css({'height': currentTallest}); } $(this).children('div').css({'min-height': currentTallest}); }); return this; };

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• swf listens to XML, AS3

  - by VideoDnd

  My swf listens to XML from a socket and document. How do I get 'my variables' to grab XML from the socket instead of the XML document? PURPOSE My purpose is to control variables with a XML Socket Server. I hope my question is clear, but ask if there's any questions. EXAMPLE Flash File import flash.net.*; import flash.display.*; import flash.events.*; import flash.system.Security; import flash.utils.Timer; import flash.events.TimerEvent; //MY VARIABLES, LINE 8-12 var timer:Timer = new Timer(10); var myString:String = ""; var count:int = 0; var myStg:String = ""; var fcount:int = 0; var xml_s=new XMLSocket(); xml_s.addEventListener(Event.CONNECT, socket_event_catcher);//OnConnect// xml_s.addEventListener(Event.CLOSE, socket_event_catcher);//OnDisconnect// xml_s.addEventListener(IOErrorEvent.IO_ERROR, socket_event_catcher);//Unable To Connect// xml_s.addEventListener(DataEvent.DATA, socket_event_catcher);//OnDisconnect// xml_s.connect("localhost", 1999); function socket_event_catcher(Event):void { switch (Event.type) { case 'ioError' : trace("ioError: " + Event.text);//Unable to Connect :(// break; case 'connect' : trace("Connection Established!");//Connected :)// break; case 'data' : trace("Received Data: " + Event.data); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var myLoader:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(myLoader); //trace("file to load URL: " + urlReq); break; case 'close' : trace("Connection Closed!");//OnDisconnect :( // xml_s.close(); break; } } //LOAD XML var myXML:XML; var myLoader:URLLoader = new URLLoader(); myLoader.load(new URLRequest("time.xml")); myLoader.addEventListener(Event.COMPLETE, processXML); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var DOINK:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(DOINK); //trace("file to load URL: " + urlReq); //PARSE XML function processXML(e:Event):void { myXML = new XML(e.target.data); trace(myXML.COUNT.text()); //-77777 //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); trace("String: ", myString); trace("Int: ", count); trace(count - 1); //just to show you that it's a number that you can do math with (-77778) //TEXT var text:TextField = new TextField(); text.text = myString; addChild(text); } Ruby Server 'Snippet' msg1 = {"msg" => {"head" => {"type" => "frctl", "seq_no" => seq_no, "version" => 1.0}, "SESSION" => {"text" => "88888", "timer" => -1000, "count" => 10, "fcount" => "10"}}} XML <?xml version="1.0" encoding="utf-8"?> <SESSION> <TIMER TITLE="speed">100</TIMER> <COUNT TITLE="starting position">88888</COUNT> <FCOUNT TITLE="ramp">1000</FCOUNT> </SESSION> ENVIROMENT AS3 Ruby 186-25 PROBLEM Coding errors "coercion of value"

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• JavaScript: How to get text from all descendents of an element, disregarding scripts?

  - by Bungle

  My current project involves gathering text content from an element and all of its descendents, based on a provided selector. For example, when supplied the selector #content and run against this HTML: <div id="content"> <p>This is some text.</p> <script type="text/javascript"> var test = true; </script> <p>This is some more text.</p> </div> my script would return (after a little whitespace cleanup): This is some text. var test = true; This is some more text. However, I need to disregard text nodes that occur within <script> elements. This is an excerpt of my current code: // get text content of all matching elements for (x = 0; x < selectors.length; x++) { matches = Sizzle(selectors[x], document); for (y = 0; y < matches.length; y++) { match = matches[y]; if (match.innerText) { // IE content += match.innerText + ' '; } else if (match.textContent) { // other browsers content += match.textContent + ' '; } } } It's a bit overly simplistic in that it just returns all text nodes within the element (and its descendants) that matches the provided selector. The solution I'm looking for would return all text nodes except for those that fall within script elements. It doesn't need to be especially high-performance, but I do need it to ultimately be cross-browser compatible. I'm assuming that I'll need to somehow loop through all children of the element that matches the selector and accumulate all text nodes other than ones within <script> elements; it doesn't look like there's any way to identify JavaScript once it's already rolled into the string accumulated from all of the text nodes. I can't use jQuery (for performance/bandwidth reasons), although you may have noticed that I do use its Sizzle selector engine, so jQuery's selector logic is available. Thanks in advance for any help!

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• Apache on Win32: Slow Transfers of single, static files in HTTP, fast in HTTPS

  - by Michael Lackner

  I have a weird problem with Apache 2.2.15 on Windows 2000 Server SP4. Basically, I am trying to serve larger static files, images, videos etc. The download seems to be capped at around 550kB/s even over 100Mbit LAN. I tried other protocols (FTP/FTPS/FTP+ES/SCP/SMB), and they are all in the multi-megabyte range. The strangest thing is that, when using Apache with HTTPS instead of HTTP, it serves very fast, around 2.7MByte/s! I also tried the AnalogX SimpleWWW server just to test the plain HTTP speed of it, and it gave me a healthy 3.3Mbyte/s. I am at a total loss here. I searched the web, and tried to change the following Apache configuration directives in httpd.conf, one at a time, mostly to no avail at all: SendBufferSize 1048576 #(tried multiples of that too, up to 100Mbytes) EnableSendfile Off #(minor performance boost) EnableMMAP Off Win32DisableAcceptEx HostnameLookups Off #(default) I also tried to tune the following registry parameters, setting their values to 4194304 in decimal (they are REG_DWORD), and rebooting afterwards: HKLM\SYSTEM\CurrentControlSet\Services\AFD\Parameters\DefaultReceiveWindow HKLM\SYSTEM\CurrentControlSet\Services\AFD\Parameters\DefaultSendWindow Additionally, I tried to install mod_bw, which sets the event timer precision to 1ms, and allows for bandwidth throttling. According to some people it boosts static file serving performance when set to unlimited bandwidth for everybody. Unfortunately, it did nothing for me. So: AnalogX HTTP: 3300kB/s Gene6 FTPD, plain: 3500kB/s Gene6 FTPD, Implicit and Explicit SSL, AES256 Cipher: 1800-2000kB/s freeSSHD: 1100kB/s SMB shared folder: about 3000kB/s Apache HTTP, plain: 550kB/s Apache HTTPS: 2700kB/s Clients that were used in the bandwidth testing: Internet Explorer 8 (HTTP, HTTPS) Firefox 8 (HTTP, HTTPS) Chrome 13 (HTTP, HTTPS) Opera 11.60 (HTTP, HTTPS) wget under CygWin (HTTP, HTTPS) FileZilla (FTP, FTPS, FTP+ES, SFTP) Windows Explorer (SMB) Generally, transfer speeds are not too high, but that's because the server machine is an old quad Pentium Pro 200MHz machine with 2GB RAM. However, I would like Apache to serve at at least 2Mbyte/s instead of 550kB/s, and that already works with HTTPS easily, so I fail to see why plain HTTP is so crippled. I am using a Kerio Winroute Firewall, but no Throttling and no special filters peeking into HTTP traffic, just the plain Firewall functionality for blocking/allowing connections. The Apache error.log (Loglevel info) shows no warnings, no errors. Also nothing strange to be seen in access.log. I have already stripped down my httpd.conf to the bare minimum just to make sure nothing is interfering, but that didn't help either. If you have any idea, help would be greatly appreciated, since I am totally out of ideas! Thanks! Edit: I have now tried a newer Apache 2.2.21 to see if it makes any difference. However, the behaviour is exactly the same. Edit 2: KM01 has requested a sniff on the HTTP headers, so here comes the LiveHTTPHeaders output (an extension to Firefox). The Output is generated on downloading a single file called "elephantsdream_source.264", which is an H.264/AVC elementary video stream under an Open Source license. I have taken the freedom to edit the URL, removing folders and changing the actual servers domain name to www.mydomain.com. Here it is: LiveHTTPHeaders, Plain HTTP: http://www.mydomain.com/elephantsdream_source.264 GET /elephantsdream_source.264 HTTP/1.1 Host: www.mydomain.com User-Agent: Mozilla/5.0 (Windows NT 5.2; WOW64; rv:6.0.2) Gecko/20100101 Firefox/6.0.2 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding: gzip, deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Connection: keep-alive HTTP/1.1 200 OK Date: Wed, 21 Dec 2011 20:55:16 GMT Server: Apache/2.2.21 (Win32) mod_ssl/2.2.21 OpenSSL/0.9.8r PHP/5.2.17 Last-Modified: Thu, 28 Oct 2010 20:20:09 GMT Etag: "c000000013fa5-29cf10e9-493b311889d3c" Accept-Ranges: bytes Content-Length: 701436137 Keep-Alive: timeout=15, max=100 Connection: Keep-Alive Content-Type: text/plain LiveHTTPHeaders, HTTPS: https://www.mydomain.com/elephantsdream_source.264 GET /elephantsdream_source.264 HTTP/1.1 Host: www.mydomain.com User-Agent: Mozilla/5.0 (Windows NT 5.2; WOW64; rv:6.0.2) Gecko/20100101 Firefox/6.0.2 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding: gzip, deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Connection: keep-alive HTTP/1.1 200 OK Date: Wed, 21 Dec 2011 20:56:57 GMT Server: Apache/2.2.21 (Win32) mod_ssl/2.2.21 OpenSSL/0.9.8r PHP/5.2.17 Last-Modified: Thu, 28 Oct 2010 20:20:09 GMT Etag: "c000000013fa5-29cf10e9-493b311889d3c" Accept-Ranges: bytes Content-Length: 701436137 Keep-Alive: timeout=15, max=100 Connection: Keep-Alive Content-Type: text/plain

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• JQuery Help: slidetoggle() is not working properly

  - by John Smith

  Hi all, I'm trying to use JQuery Slidetoggle functionality, but not able to use properly. The problem I'm currently facing is my div is sliding down on the click of slide image icon, but after that suddenly data div (in which data is loading) disappears. Means sliding down is perfect but div (in which data is loading , here #divMain) is not visible after that. I want to achieve sliding effect in my code, like this has (Please see Website Design, Redesign Services slider): Here is my code: HTML: <div> <div class="jquery_inner_mid"> <div class="main_heading"> <a href="#"> <img src="features.jpg" alt="" title="" border="0" /></a> </div> <div class="plus_sign"> <img id="imgFeaturesEx" src="images/plus.jpg" alt="" title="" border="0" /> <img id="imgFeaturesCol" src="images/minus.jpg" alt="" title="" border="0" /></div> <div class="toggle_container"> <div id="divMain" > </div> </div> </div> <div class="jquery_inner_mid"> <div class="main_heading"> <img src="About.jpg" alt="" title="" /></div> <div class="plus_sign"> <img id="imgTechnoEx" src="images/plus.jpg" alt="" title="" border="0" /> <img id="imgTechnoCol" src="images/minus.jpg" alt="" title="" border="0" /></div> <div class="toggle_container"> <div id="divTechnossus" > </div> </div> </div> </div> JQuery: $(function() { $('#imgFeaturesCol').hide(); $('#imgTechnoCol').hide(); $('#imgFeaturesEx').click(function() { $.getJSON("/Visitor/GetFeatureInfo", null, function(strInfo) { $('#divMain').html(strInfo).slideToggle("slow"); LoadDiv(); }); $('#imgFeaturesEx').hide(); $('#imgFeaturesCol').show(); }); $('#imgFeaturesCol').click(function() { $('#divMain').html("").slideToggle("slow"); $('#imgFeaturesCol').hide(); $('#imgFeaturesEx').show(); }); $('#imgTechnoEx').click(function() { $.getJSON("/Visitor/GetTechnossusInfo", null, function(strInfo) { $('#divTechnossus').html(strInfo).slideToggle("slow"); }); $('#imgTechnoEx').hide(); $('#imgTechnoCol').show(); }); $('#imgTechnoCol').click(function() { $('#divTechnossus').html("").slideToggle("slow"); $('#imgTechnoCol').hide(); $('#imgTechnoEx').show(); }); })(); function LoadDiv() { $('#s4').cycle({ speed: 200, timeout: 0, pager: '#nav' }); }

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• Writing Device Drivers for Microcontrollers, where to define IO Port pins?

  - by volting

  I always seem to encounter this dilemma when writing low level code for MCU's. I never know where to declare pin definitions so as to make the code as reusable as possible. In this case Im writing a driver to interface an 8051 to a MCP4922 12bit serial DAC. Im unsure how/where I should declare the pin definitions for The CS(chip select) and LDAC(data latch) for the DAC. At the moment there declared in the header file for the driver. Iv done a lot of research trying to figure out the best approach but havent really found anything. Im basically want to know what the best practices... if there are some books worth reading or online information, examples etc, any recommendations would be welcome. Just a snippet of the driver so you get the idea /** @brief This function is used to write a 16bit data word to DAC B -12 data bit plus 4 configuration bits @param dac_data A 12bit word @param ip_buf_unbuf_select Input Buffered/unbuffered select bit. Buffered = 1; Unbuffered = 0 @param gain_select Output Gain Selection bit. 1 = 1x (VOUT = VREF * D/4096). 0 =2x (VOUT = 2 * VREF * D/4096) */ void MCP4922_DAC_B_TX_word(unsigned short int dac_data, bit ip_buf_unbuf_select, bit gain_select) { unsigned char low_byte=0, high_byte=0; CS = 0; /**Select the chip*/ high_byte |= ((0x01 << 7) | (0x01 << 4)); /**Set bit to select DAC A and Set SHDN bit high for DAC A active operation*/ if(ip_buf_unbuf_select) high_byte |= (0x01 << 6); if(gain_select) high_byte |= (0x01 << 5); high_byte |= ((dac_data >> 8) & 0x0F); low_byte |= dac_data; SPI_master_byte(high_byte); SPI_master_byte(low_byte); CS = 1; LDAC = 0; /**Latch the Data*/ LDAC = 1; }

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• Another C datatypes question

  - by b-gen-jack-o-neill

  Hello. Well, I completely get the most basic datatypes of C, like short, int, long, float, to be exact, all numerical types.These types are needed to be known perform right operations with right numbers. For example to use FPU to add two float numbers. So the compiler must know what the type is. But, when it comes to characters I am little bit off. I know that basic C datatype char is there for ASCII characters coding. But what I don´t know is, why you even need another datatype for characters. Why could not you just use 1 byte integer value to store ASCII character. If you call printf, you apecify the datatype in the call, so you could say to printf that the integer represents ASCII character. I dont know how cout resolves datatype, but I guess you could just specify it somehow. Another thing is, when you want to use Unicode, you must use datatype wchar. But, what if I would like to use some another, for example ISO, or Windows coding instead of UTF? Becouse wchar codes characters as UTF-16 or UTF-32 (I read its compiler specific). And, what if I would want to use for example some imaginary new 8 byte text coding? What datatype should I use for it? I am actually pretty confused of this, becouse I always expected that if I want to use UTF-32 instead of ASCII, I just tell compiler "get UTF-32 value of the character I typed and save it into 4 char field." I thought that text coding is to be dealt with by the end, print function for example. That I just need to specify the coding for the compiler to use, since Windows doesent use ASCII in win32 apps, I guess C compiler must convert the char I typed to ASCII from whatever the type is that windows sends to the C editor. And the last thing is, what if I want to use for example 25 Byte integer for some high math operations? C has no specify-yourself datatype. Yes, I know that this would be difficult since all the math operations would need to be changed, becouse CPU can not add 25 Bytes numbers together. But is there a way to do it? Or is there some math library for it? What if I want to compute Pi to 1000000000000000 digits? :) I know my question is pretty long, but I just wanted to explain my thoughts the best I can in English, since its not my native language it is difficult. And I believe there is simple answer to my question(s), something I missed that explains everything. I read lot about text coding, C tutorials, but nothing about his. Thank you for your time.

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• My server app works strangely. What could be the reason(s)?

  - by Poni

  Hi! I've written a server app (two parts actually; proxy server and a game server) using C++ (board game). It uses IOCP as the sockets interface. For that app I've also written a "client simulator" (hereafter "client") app that spawns many client connections, where each of them plays, in very high speed, getting the CPU to be 100% utilized. So, that's how it goes in terms of topology: Game server - holds the game state. Real players do not connect it directly but through the proxy server. When a player joins a game, the proxy actually asks for it on behalf of that player, and the game server spawns a "player instance" for that player, and from now on, every notification between the game server and the player is being passed through the proxy. Proxy server - holds TCP connections with the real players. Players communicate with the game server through it only. Client simulator - connects to the proxy only. When running the server (again, it's actually two server apps) & client locally it all works just fine. I'm talking about 40k+ player instances in which all of them are active in a game. On the other hand, when running the server remotely with, say, 1000 clients who play things getting strange. For example, I run it as said above. Then with Task Manager I kill the client simulator app ("End Process Tree"). Then it seems like the buffer of the remote server got modified by another thread, or in other words, a memory corruption has been occurred. The server crashes because it got an unknown message id (it's a custom protocol where each message has it's own unique number). To make things clear, here is how I run the apps: PC1 - game server and clients simulator (because the clients will connect the proxy). PC2 - proxy server. The strangest thing is this: Only the remote side gets "corrupted". Remote in terms that it's not the PC I use to code the app (VC++ 2008). Let's call the PC I use to code the apps "PC1". Now for example, if this time I ran the game server on PC1 (it means that proxy server on PC2 and clients simulator on PC1), then the proxy server crashes with an "unknown message id" error. Another variation is when I run the proxy server on PC1 (again, the dev machine), the game server and the clients simulator on PC2, then the game server on PC2 gets crashed. As for the IOCP config: The servers' internal connections use the default receive/send buffer sizes. Tried even with setting them to 1MB, but no luck. I have three PCs in total; 2 x Vista 64bit <<-- one of those is the dev machine. The other is connected through WiFi. 1 x WinXP 32bit They're all connected in a "full duplex" manner. What could be the reason? Tried about everything; Stack tracing, recording some actions (like read/write logging).. I want to stress that only the PC I'm not using to code the apps crashes (actually the server app "role" which is running on it - sometimes the game server and sometimes the proxy server). At first I thought that maybe the wireless PC has problems (it's wireless..) but: TCP has it's own mechanisms to make sure the packet is delivered properly. Also, a crash also happens when trying it with the two PCs that are physically connected (Vista vs. XP). Another option is that the Windows DLLs versions might have problems, but then again, one of the tests is Vista vs. Vista, and the other is Vista vs. XP. Any idea?

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• Looking for Fiddler2 help. connection to gateway refused? Just got rid of a virus

  - by John Mackey

  I use Fiddler2 for facebook game items, and it's been a great success. I accessed a website to download some dat files I needed. I think it was eshare, ziddu or megaupload, one of those. Anyway, even before the rar file had downloaded, I got this weird green shield in the bottom right hand corner of my computer. It said a Trojan was trying to access my computer, or something to that extent. It prompted me to click the shield to begin anti-virus scanning. It turns out this rogue program is called Antivirus System Pro and is pretty hard to get rid of. After discovering the rogue program, I tried using Fiddler and got the following error: [Fiddler] Connection to Gateway failed.Exception Text: No connection could be made because the target machine actively refused it 127.0.0.1:5555 I ended up purchasing SpyDoctor + Antivirus, which I'm told is designed specifically for getting rid of these types of programs. Anyway, I did a quick-scan last night with spydoctor and malware bytes. Malware picked up 2 files, and Spydoctor found 4. Most were insignificant, but it did find a worm called Worm.Alcra.F, which was labeled high-priority. I don’t know if that’s the Anti-Virus Pro or not, but SpyDoctor said it got rid of all of those successfully. I tried to run Fiddler again before leaving home, but was still getting the "gateway failed" error. Im using the newest version of firefox. When I initially set up the Fiddler 2.2.8.6, I couldn’t get it to run at first, so I found this faq on the internet that said I needed to go through ToolsOptionsSettings and set up an HTTP Proxy to 127.0.0.1 and my Port to 8888. Once I set that up and downloaded this fiddler helper as a firefox add-on, it worked fine. When I turn on fiddler, it automatically takes my proxy setting from no proxy (default) to the 127.0.0.1 with Port 8888 set up. It worked fine until my computer detected this virus. Anyway, hopefully I've given you sufficient information to offer me your best advice here. Like I said, Spydoctor says the bad stuff is gone, so maybe the rogue program made some type of change in my fiddler that I could just reset or uncheck or something like that? Or will I need to completely remove fiddler and those dat files and rar files I downloaded? Any help would be greatly appreciated. Thanks for your time.

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• ublas::bounded_vector<> being resized?

  - by n2liquid

  Now, seriously... I'll refrain from using bad words here because we're talking about the Boost fellows. It MUST be my mistake to see things this way, but I can't understand why, so I'll ask it here; maybe someone can enlighten me in this matter. Here it goes: uBLAS has this nice class template called bounded_vector<> that's used to create fixed-size vectors (or so I thought). From the Effective uBLAS wiki (http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Effective_UBLAS): The default uBLAS vector and matrix types are of variable size. Many linear algebra problems involve vectors with fixed size. 2 and 3 elements are common in geometry! Fixed size storage (akin to C arrays) can be implemented efficiently as it does not involve the overheads (heap management) associated with dynamic storage. uBLAS implements fixed sizes by changing the underling storage of a vector/matrix to a "bounded_array" from the default "unbounded_array". Alright, this bounded_vector<> thing is used to free you from specifying the underlying storage of the vector to a bounded_array<> of the specified size. Here I ask you: doesn't it look like this bounded vector thing has fixed size to you? Well, it doesn't have. At first I felt betrayed by the wiki, but then I reconsidered the meaning of "bounded" and I think I can let it pass. But in case you, like me (I'm still uncertain), is still wondering if this makes sense, what I found out is that the bounded_vector<> actually can be resized, it may only not be greater than the size specified as template parameter. So, first off, do you think they've had a good reason not to make a real fixed<< size vector or matrix type? Do you think it's okay to "sell" this bounded -- as opposed to fixed-size -- vector to the users of my library as a "fixed-size" vector replacement, even named "Vector3" or "Vector2", like the Effective uBLAS wiki did? Do you think I should somehow implement a vector with fixed size for this purpose? If so, how? (Sorry, but I'm really new to uBLAS; just tried it today) I am developing a 3D game. Should uBLAS be used for the calculations involved in this ("hey, geometry!", per Effective uBLAS wiki)? What replacement would you suggest, if not? -- edit And just in case, yes, I've read this warning: It should be noted that this only changes the storage uBLAS uses for the vector3. uBLAS will still use all the same algorithm (which assume a variable size) to manipulate the vector3. In practice this seems to have no negative impact on speed. The above runs just as quickly as a hand crafted vector3 which does not use uBLAS. The only negative impact is that the vector3 always store a "size" member which in this case is redundant [or isn't it? I mean......]. I see it uses the same algorithm, assuming a variable size, but if an operation were to actually change its size, shouldn't it be stopped (assertion)? ublas::bounded_vector<float,3> v3; ublas::bounded_vector<float,2> v2; v3 = v2; std::cout << v3.size() << '\n'; // prints 2 Oh, come on, isn't this just plain betrayal?

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• What is the best algorithm for this array-comparison problem?

  - by mark

  What is the most efficient for speed algorithm to solve the following problem? Given 6 arrays, D1,D2,D3,D4,D5 and D6 each containing 6 numbers like: D1[0] = number D2[0] = number ...... D6[0] = number D1[1] = another number D2[1] = another number .... ..... .... ...... .... D1[5] = yet another number .... ...... .... Given a second array ST1, containing 1 number: ST1[0] = 6 Given a third array ans, containing 6 numbers: ans[0] = 3, ans[1] = 4, ans[2] = 5, ......ans[5] = 8 Using as index for the arrays D1,D2,D3,D4,D5 and D6, the number that goes from 0, to the number stored in ST1[0] minus one, in this example 6, so from 0 to 6-1, compare each res array against each D array My algorithm so far is: I tried to keep everything unlooped as much as possible. EML := ST1[0] //number contained in ST1[0] EML1 := 0 //start index for the arrays D While EML1 < EML if D1[ELM1] = ans[0] goto two if D2[ELM1] = ans[0] goto two if D3[ELM1] = ans[0] goto two if D4[ELM1] = ans[0] goto two if D5[ELM1] = ans[0] goto two if D6[ELM1] = ans[0] goto two ELM1 = ELM1 + 1 return 0 //If the ans[0] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers two: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[1] goto three if D2[ELM1] = ans[1] goto three if D3[ELM1] = ans[1] goto three if D4[ELM1] = ans[1] goto three if D5[ELM1] = ans[1] goto three if D6[ELM1] = ans[1] goto three ELM1 = ELM1 + 1 return 0 //If the ans[1] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers three: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[2] goto four if D2[ELM1] = ans[2] goto four if D3[ELM1] = ans[2] goto four if D4[ELM1] = ans[2] goto four if D5[ELM1] = ans[2] goto four if D6[ELM1] = ans[2] goto four ELM1 = ELM1 + 1 return 0 //If the ans[2] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers four: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[3] goto five if D2[ELM1] = ans[3] goto five if D3[ELM1] = ans[3] goto five if D4[ELM1] = ans[3] goto five if D5[ELM1] = ans[3] goto five if D6[ELM1] = ans[3] goto five ELM1 = ELM1 + 1 return 0 //If the ans[3] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers five: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[4] goto six if D2[ELM1] = ans[4] goto six if D3[ELM1] = ans[4] goto six if D4[ELM1] = ans[4] goto six if D5[ELM1] = ans[4] goto six if D6[ELM1] = ans[4] goto six ELM1 = ELM1 + 1 return 0 //If the ans[4] number is not found in either D1[0-6], D2[0-6].... D6[0-6] return 0 which will then exclude ans[0-6] numbers six: EML1 := 0 start index for arrays Ds While EML1 < EML if D1[ELM1] = ans[5] return 1 ////If the ans[1] number is not found in either D1[0-6]..... if D2[ELM1] = ans[5] return 1 which will then include ans[0-6] numbers return 1 if D3[ELM1] = ans[5] return 1 if D4[ELM1] = ans[5] return 1 if D5[ELM1] = ans[5] return 1 if D6[ELM1] = ans[5] return 1 ELM1 = ELM1 + 1 return 0 As language of choice, it would be pure c

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• Cobol: science and fiction

  - by user847

  There are a few threads about the relevance of the Cobol programming language on this forum, e.g. this thread links to a collection of them. What I am interested in here is a frequently repeated claim based on a study by Gartner from 1997: that there were around 200 billion lines of code in active use at that time! I would like to ask some questions to verify or falsify a couple of related points. My goal is to understand if this statement has any truth to it or if it is totally unrealistic. I apologize in advance for being a little verbose in presenting my line of thought and my own opinion on the things I am not sure about, but I think it might help to put things in context and thus highlight any wrong assumptions and conclusions I have made. Sometimes, the "200 billion lines" number is accompanied by the added claim that this corresponded to 80% of all programming code in any language in active use. Other times, the 80% merely refer to so-called "business code" (or some other vague phrase hinting that the reader is not to count mainstream software, embedded systems or anything else where Cobol is practically non-existent). In the following I assume that the code does not include double-counting of multiple installations of the same software (since that is cheating!). In particular in the time prior to the y2k problem, it has been noted that a lot of Cobol code is already 20 to 30 years old. That would mean it was written in the late 60ies and 70ies. At that time, the market leader was IBM with the IBM/370 mainframe. IBM has put up a historical announcement on his website quoting prices and availability. According to the sheet, prices are about one million dollars for machines with up to half a megabyte of memory. Question 1: How many mainframes have actually been sold? I have not found any numbers for those times; the latest numbers are for the year 2000, again by Gartner. :^( I would guess that the actual number is in the hundreds or the low thousands; if the market size was 50 billion in 2000 and the market has grown exponentially like any other technology, it might have been merely a few billions back in 1970. Since the IBM/370 was sold for twenty years, twenty times a few thousand will result in a couple of ten-thousands of machines (and that is pretty optimistic)! Question 2: How large were the programs in lines of code? I don't know how many bytes of machine code result from one line of source code on that architecture. But since the IBM/370 was a 32-bit machine, any address access must have used 4 bytes plus instruction (2, maybe 3 bytes for that?). If you count in operating system and data for the program, how many lines of code would have fit into the main memory of half a megabyte? Question 3: Was there no standard software? Did every single machine sold run a unique hand-coded system without any standard software? Seriously, even if every machine was programmed from scratch without any reuse of legacy code (wait ... didn't that violate one of the claims we started from to begin with???) we might have O(50,000 l.o.c./machine) * O(20,000 machines) = O(1,000,000,000 l.o.c.). That is still far, far, far away from 200 billion! Am I missing something obvious here? Question 4: How many programmers did we need to write 200 billion lines of code? I am really not sure about this one, but if we take an average of 10 l.o.c. per day, we would need 55 million man-years to achieve this! In the time-frame of 20 to 30 years this would mean that there must have existed two to three million programmers constantly writing, testing, debugging and documenting code. That would be about as many programmers as we have in China today, wouldn't it? Question 5: What about the competition? So far, I have come up with two things here: 1) IBM had their own programming language, PL/I. Above I have assumed that the majority of code has been written exclusively using Cobol. However, all other things being equal I wonder if IBM marketing had really pushed their own development off the market in favor of Cobol on their machines. Was there really no relevant code base of PL/I? 2) Sometimes (also on this board in the thread quoted above) I come across the claim that the "200 billion lines of code" are simply invisible to anybody outside of "governments, banks ..." (and whatnot). Actually, the DoD had funded their own language in order to increase cost effectiveness and reduce the proliferation of programming language. This lead to their use of Ada. Would they really worry about having so many different programming languages if they had predominantly used Cobol? If there was any language running on "government and military" systems outside the perception of mainstream computing, wouldn't that language be Ada? I hope someone can point out any flaws in my assumptions and/or conclusions and shed some light on whether the above claim has any truth to it or not.

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• Why do some questions get closed for no reason? [closed]

  - by IVlad

  Recently there was a question asking about generating all subsets of a set using a stack and a queue, which was closed (and now deleted it seems) as not a real question for no good reason, since it didn't fit into any of these conditions: It's difficult to tell what is being asked here. No, it was clear what was being asked. This question is ambiguous, vague, incomplete, or rhetorical and cannot be reasonably answered in its current form. Not ambiguous, not vague, not incomplete, definitely not rhetorical and could easily be answered if one knew the solution. Now, the exact same thing has happened with this question: http://stackoverflow.com/questions/2791982/a-shortest-path-problem-with-superheroes-and-intergalactic-journeys/2793746#2793746 I am interested in hearing a logical argument for why that question is either ambiguous, vague, incomplete, rhetorical or cannot reasonably be answered in its current form. It seems that (the same bunch of) people like to close questions that they think are homework questions, especially when they think people want to be served the solution on a platter, which is also not the case: Any suggestions or ideas of how this problem might be solved would be most welcomed. Most of the time the people asking these questions are very reasonable and appreciate even the most vague idea, yet their question is closed. Let's go further and assume that it IS a homework problem. So what? When I registered here I didn't see any rule that said not to post homework problems, nor do I see such a rule now. What is wrong with posting homework problems that makes people hunt them down with a passion to close them without even reading the entire question body? This site is full of questions asked by people who get paid to know the things they are asking, yet their questions are considered fine. How is solving someone's homework problem worse? In some places (like where I live), computer science is a mandatory high school subject, and not everyone is interested in it. How is helping at least those people worse than doing someone's JOB? Not answering homework questions is fine and it's everyone's choice, but I consider closing them to be an act of power abuse, selfishness, and an insult to the fellow community members who are also interested in a solution or want feedback on their proposed solution. So my questions are: - Why do questions like the above get closed for reasons that do not apply? Why do you close them? Why don't you? - Why doesn't a vote to reopen a question reopen it automatically? Needing 5 votes for a reopen takes too long, and it's not fair because one reopen vote basically cancels out a close vote, making it 4 close votes (or 5 to 1, which is the same as only 4 people wanting to close the question), which isn't enough to close the question. I think a question should only be closed when CloseVotes - ReopenVotes >= 5. I'm hoping this will stay up, but I realize it probably won't. In either case, I think this is worth saying and discussing, since it IS community-related.

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• Why is my mdadm raid-1 recovery so slow?

  - by dimmer

  On a system I'm running Ubuntu 10.04. My raid-1 restore started out fast but quickly became ridiculously slow (at this rate the restore will take 150 days!): dimmer@paimon:~$ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdc1[2] sdb1[1] 1953513408 blocks [2/1] [_U] [====>................] recovery = 24.4% (477497344/1953513408) finish=217368.0min speed=113K/sec unused devices: <none> Eventhough I have set the kernel variables to reasonably quick values: dimmer@paimon:~$ cat /proc/sys/dev/raid/speed_limit_min 1000000 dimmer@paimon:~$ cat /proc/sys/dev/raid/speed_limit_max 100000000 I am using 2 2.0TB Western Digital Hard Disks, WDC WD20EARS-00M and WDC WD20EARS-00J. I believe they have been partitioned such that their sectors are aligned. dimmer@paimon:/sys$ sudo parted /dev/sdb GNU Parted 2.2 Using /dev/sdb Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) p Model: ATA WDC WD20EARS-00M (scsi) Disk /dev/sdb: 2000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 2000GB 2000GB ext4 (parted) unit s (parted) p Number Start End Size File system Name Flags 1 2048s 3907028991s 3907026944s ext4 (parted) q dimmer@paimon:/sys$ sudo parted /dev/sdc GNU Parted 2.2 Using /dev/sdc Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) p Model: ATA WDC WD20EARS-00J (scsi) Disk /dev/sdc: 2000GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 2000GB 2000GB ext4 I am beginning to think that I have a hardware problem, otherwise I can't imagine why the mdadm restore should be so slow. I have done a benchmark on /dev/sdc using Ubuntu's disk utility GUI app, and the results looked normal so I know that sdc has the capability to write faster than this. I also had the same problem on a similar WD drive that I RMAd because of bad sectors. I suppose it's possible they sent me a replacement with bad sectors too, although there are no SMART values showing them yet. Any ideas? Thanks. As requested, output of top sorted by cpu usage (notice there is ~0 cpu usage). iowait is also zero which seems strange: top - 11:35:13 up 2 days, 9:40, 3 users, load average: 2.87, 2.58, 2.30 Tasks: 142 total, 1 running, 141 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.2%sy, 0.0%ni, 99.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3096304k total, 1482164k used, 1614140k free, 617672k buffers Swap: 1526132k total, 0k used, 1526132k free, 535416k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 45 root 20 0 0 0 0 S 0 0.0 2:17.02 scsi_eh_0 1 root 20 0 2808 1752 1204 S 0 0.1 0:00.46 init 2 root 20 0 0 0 0 S 0 0.0 0:00.00 kthreadd 3 root RT 0 0 0 0 S 0 0.0 0:00.02 migration/0 4 root 20 0 0 0 0 S 0 0.0 0:00.17 ksoftirqd/0 5 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0 6 root RT 0 0 0 0 S 0 0.0 0:00.02 migration/1 ... dmesg errors, definitely looking like hardware: [202884.000157] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [202884.007015] ata5.00: failed command: FLUSH CACHE EXT [202884.013728] ata5.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0 [202884.013730] res 40/00:00:ff:59:2e/00:00:35:00:00/e0 Emask 0x4 (timeout) [202884.033667] ata5.00: status: { DRDY } [202884.040329] ata5: hard resetting link [202889.400050] ata5: link is slow to respond, please be patient (ready=0) [202894.048087] ata5: COMRESET failed (errno=-16) [202894.054663] ata5: hard resetting link [202899.412049] ata5: link is slow to respond, please be patient (ready=0) [202904.060107] ata5: COMRESET failed (errno=-16) [202904.066646] ata5: hard resetting link [202905.840056] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [202905.849178] ata5.00: configured for UDMA/133 [202905.849188] ata5: EH complete [203899.000292] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [203899.007096] ata5.00: failed command: IDENTIFY DEVICE [203899.013841] ata5.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in [203899.013843] res 40/00:00:ff:f9:f6/00:00:38:00:00/e0 Emask 0x4 (timeout) [203899.041232] ata5.00: status: { DRDY } [203899.048133] ata5: hard resetting link [203899.816134] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [203899.826062] ata5.00: configured for UDMA/133 [203899.826079] ata5: EH complete [204375.000200] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [204375.007421] ata5.00: failed command: IDENTIFY DEVICE [204375.014799] ata5.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in [204375.014800] res 40/00:00:ff:0c:0f/00:00:39:00:00/e0 Emask 0x4 (timeout) [204375.044374] ata5.00: status: { DRDY } [204375.051842] ata5: hard resetting link [204380.408049] ata5: link is slow to respond, please be patient (ready=0) [204384.440076] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [204384.449938] ata5.00: configured for UDMA/133 [204384.449955] ata5: EH complete [204395.988135] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [204395.988140] ata5.00: failed command: IDENTIFY DEVICE [204395.988147] ata5.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in [204395.988149] res 40/00:00:ff:0c:0f/00:00:39:00:00/e0 Emask 0x4 (timeout) [204395.988151] ata5.00: status: { DRDY } [204395.988156] ata5: hard resetting link [204399.320075] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [204399.330487] ata5.00: configured for UDMA/133 [204399.330503] ata5: EH complete

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• PHP MINISERVER DOWNLOAD RESUME-ERROR! Resource id # 4

  - by snikolov

  $httpsock = @socket_create_listen("9090"); if (!$httpsock) { print "Socket creation failed!\n"; exit; } while (1) { $client = socket_accept($httpsock); $input = trim(socket_read ($client, 4096)); $input = explode(" ", $input); $range = $input[12]; $input = $input[1]; $fileinfo = pathinfo($input); switch ($fileinfo['extension']) { default: $mime = "text/html"; } if ($input == "/") { $input = "index.html"; } $input = ".$input"; if (file_exists($input) && is_readable($input)) { echo "Serving $input\n"; $contents = file_get_contents($input); $output = "HTTP/1.0 200 OK\r\nServer: APatchyServer\r\nConnection: close\r\nContent-Type: $mime\r\n\r\n$contents"; } else { //$contents = "The file you requested doesn't exist. Sorry!"; //$output = "HTTP/1.0 404 OBJECT NOT FOUND\r\nServer: BabyHTTP\r\nConnection: close\r\nContent-Type: text/html\r\n\r\n$contents"; if(isset($range)) { list($a, $range) = explode("=",$range); str_replace($range, "-", $range); $size2 = $size-1; $new_length = $size-$range; $output = "HTTP/1.1 206 Partial Content\r\n"; $output .= "Content-Length: $new_length\r\n"; $output .= "Content-Range: bytes $range$size2/$size\r\n"; } else { $size2=$size-1; $output .= "Content-Length: $new_length\r\n"; } $chunksize = 1*(1024*1024); $bytes_send = 0; $file = "a.mp3"; $filesize = filesize($file); if ($file = fopen($file, 'r')) { if(isset($range)) $output = 'HTTP/1.0 200 OK\r\n'; $output .= "Content-type: application/octet-stream\r\n"; $output .= "Content-Length: $filesize\r\n"; $output .= 'Content-Disposition: attachment; filename="'.$file.'"\r\n'; $output .= "Accept-Ranges: bytes\r\n"; $output .= "Cache-Control: private\n\n"; fseek($file, $range); $download_rate = 1000; while(!feof($file) and (connection_status()==0)) { $var_stat = fread($file, round($download_rate *1024)); $output .= $var_stat;//echo($buffer); // is also possible flush(); sleep(1);//// decrease download speed } fclose($file); } /** $filename = "dada"; $file = fopen($filename, 'r'); $filesize = filesize($filename); $buffer = fread($file, $filesize); $send = array("Output"=$buffer,"filesize"=$filesize,"filename"=$filename); $file = $send['filename']; */ //@ob_end_clean(); // $output .= "Content-Transfer-Encoding: binary"; //$output .= "Connection: Keep-Alive\r\n"; } socket_write($client, $output); socket_close ($client); } socket_close ($httpsock); hey guys i have create a miniwebserver downloader it can download files from your server, however i am unable to resume my download when i download the file i get Resource id # 4 and also i cant resume the download,i would like to know how i can monitor record the client output how much bandwidth he has downloaded perl has something like this put its hardcore if possible kindly provide me with some pointers thank you :)

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• How do I get through proxy server environments for non-standard services?

  - by Ripred

  I'm not real hip on exactly what role(s) today's proxy servers can play and I'm learning so go easy on me :-) I have a client/server system I have written using a homegrown protocol and need to enhance the client side to negotiate its way out of a proxy environment. I have an existing client and server system written in C and C++ for the speed and a small amount of MFC in the client to handle the user interface. I have written both the server and client side of the system on Windows (the people I work for are mainly web developers using Windows everything - not a choice) sticking to Berkeley Sockets as it were via wsock32 for efficiency. The clients connect to the server through a nonstandard port (even though using port 80 is an option to get out of some environments but the protocol that goes over it isn't HTTP). The TCP connection(s) stay open for the duration of the clients participation in real time conferences. Our customer base is expanding to all kinds of networked environments. I have been able to solve a lot of problems by adding the ability to connect securely over port 443 and using secure sockets which allows the protocol to pass through a lot environments since the internal packets can't be sniffed. But more and more of our customers are behind a proxy server environment and my direct connections don't make it through. My old school understanding of proxy servers is that they act as a proxy for external HTML content over HTTP, possibly locally caching popular material for faster local access, and also allowing their IT staff to blacklist certain destination sites. Customer are complaining that my software doesn't recognize and easily navigate its way through their proxy environments but I'm finding it difficult to decide what my "best fit" solution should be. My software doesn't tear down the connection after each client request, and on top of that packets can come from either side at any time, basically your typical custom client/server system for a specific niche. My first reaction is "why can't they just add my servers addresses to their white list" but if there is a programmatic way I can get through without requiring their IT staff to help it is politically better and arguably a better solution anyway. Plus maybe I'm still not understanding the role and purpose of what proxy servers and environments have grown to be these days. My first attempt at a solution was to use WinInet with its various proxy capabilities to establish a connection over port 80 to my non-standard protocol server (which knows enough to recognize and answer a simple HTTP-looking GET request and answer it with a simple HTTP response page to get around some environments that employ initial packet sniffing (DPI)). I retrieved the actual SOCKET handle behind WinInet's HINTERNET request object and had hoped to use that in place of my software's existing SOCKET connection and hopefully not need to change much more on the client side. It initially seemed to be my solution but on further inspection it seems that the OS gets first-chance at the received data on this socket since when I get notified of events via the standard select(...) statement on the socket and query the size of the data available via ioctlsocket the call succeeds but returns 0 bytes available, the reads don't work and it goes downhill from there. Can someone tell me of a client-side library (commercial is fine) will let me get past these proxy server environments with as little user and IT staff help as possible? From what I read it has grown past SOCKS and I figure someone has to have solved this problem before me. Thanks for reading my long-winded question, Ripred

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• My D-Link's Ethernet bridge downlink just got 10-30x slower?

  - by Jay Levitt

  TL;DR: I unplugged my network to move my desk, and now downloading via my DIR-655's Ethernet LAN bridge is 10-30x slower than the Ethernet switch it's plugged into. Background My network is SMC cable modem <-> Cisco firewall <-> Netgear switch <-> D-Link WiFi† | | | | SMC8014 ASA-5505 GS608v2 gigE DIR-655 rev A3 gigE †The DIR-655 is used as an access point, not a router (although what D-Link calls an access point, I'd call a bridge). The "WAN" port is unused; the Netgear connects to the built-in 4-port Ethernet LAN switch, inside the built- in router/firewall. Endpoints: MacBook Pro 17" mid-2010 iPhone 4S Fedora 12 Linux server running reasonably fast dual-Athlon X2, VelociRaptors, etc. All cables are <10 feet, mostly CAT-5e, some CAT-6, all premade. All WiFi endpoints are within three feet of the D-Link. Yesterday I unplugged and rearranged stuff, and now connecting via the D-Link - even through the wired switch, right next to the incoming network cable - is 30x slower than connecting directly to the Netgear switch, on both my MacBook and iPhone. How I'm measuring "slower" I'm mostly using http://speedtest.net, which of course only really measures broadband speeds. I've also installed http://www.speedtest.net/mini.php on my local server, but can't test the iPhone with that. Results Speedtest.net, closest server over Comcast business-class: CONFIG | PING (ms) | DOWN (Mbps) | UP (Mbps) Mac <-> Ethernet <-> Netgear | 9 | 31.6 | 6.8 Mac <-> Ethernet <-> D-Link | 8 | 4.1 | 6.0 Mac <-> WiFi <-> D-Link | 9 | 1.4 | 2.9 iPhone <-> WiFi <-> D-Link | 67 | 0.4 | 1.6 Speedtest Mini on Linux PC: CONFIG | DOWN (Mbps) | UP (Mbps) Mac <-> Ethernet <-> NetGear | 97.2 | 76.9 Mac <-> Ethernet <-> D-Link | 8.2 | 24.2 Mac <-> WiFi <-> D-Link | 1.0 | 8.6 Slow typing in SSH: Mac <-> Ethernet <-> Netgear <-> Linux PC: smooth Mac <-> Ethernet <-> D-Link <-> Linux PC: choppy Note that D-Link upload speeds are normal on broadband, slower locally (but I'd believe that's a D-Link limitation), and always faster than the downloads! Since ssh is choppy just with slow typing, I don't believe it's a throttling-type problem either; that's not a lot of bandwidth. What I've tried Swapping all "good" and "bad" cables Re-plugging "bad" cable from D-Link to Netgear and watching it be the "good" cable pulling cables away from power lines Verify that the Mac auto-detects the D-Link as gigE Try to verify the link speed of the D-Link <- Netgear connection, but the firmware doesn't report that Verify that the D-Link sees no TX/RX errors or collisions Use different Ethernet ports on both Netgear and D-Link Reset the D-Link to factory settings Upgrade the D-Link firmware from 1.21 to 1.35NA, 2010/11/12, the latest Reboot everything at least once On the Mac, disable Wi-Fi during the Ethernet tests, and unplug Ethernet during the Wi-Fi tests Using iStumbler, verify that the D-Link isn't picking overloaded Wi-Fi channels (usually just 1-5 neighbors on my and adjacent channels, average for my apt building) Verify that the only client connected to the Wi-Fi was the iPhone Verify that nothing was being chatty on my network according to the WISH log Enable and disable all sorts of D-Link settings, including forcing WAN auto-detect to gigE So. I don't mind buying a new access point—I wouldn't mind having a dual-link network—but as a guy who's been networking since gated v4 was a drastic rewrite, and who often used physical sniffers in the days before Wireshark, I'm baffled. I hate being baffled. What could I possibly have changed that would result in this? How can I measure it? All I can think of is a static zap—thick carpet, socks, HVAC—but I didn't feel one, and does that really happen anymore? Can I test if it's Ethernet vs. TCP layer slowness? I'm not familiar with modern network utilities; it's hard to Google without hitting "Q: Why is my network slow? A: Is your microwave on?" If I don't get an answer here, will someone big and powerful help me migrate it to serverfault without getting screamed back here? In the words of Inigo Montoya, "I must know." Don't get all Dread Pirate Roberts on me.

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• Why do I get rows of zeros in my 2D fft?

  - by Nicholas Pringle

  I am trying to replicate the results from a paper. "Two-dimensional Fourier Transform (2D-FT) in space and time along sections of constant latitude (east-west) and longitude (north-south) were used to characterize the spectrum of the simulated flux variability south of 40degS." - Lenton et al(2006) The figures published show "the log of the variance of the 2D-FT". I have tried to create an array consisting of the seasonal cycle of similar data as well as the noise. I have defined the noise as the original array minus the signal array. Here is the code that I used to plot the 2D-FT of the signal array averaged in latitude: import numpy as np from numpy import ma from matplotlib import pyplot as plt from Scientific.IO.NetCDF import NetCDFFile ### input directory indir = '/home/nicholas/data/' ### get the flux data which is in ### [time(5day ave for 10 years),latitude,longitude] nc = NetCDFFile(indir + 'CFLX_2000_2009.nc','r') cflux_southern_ocean = nc.variables['Cflx'][:,10:50,:] cflux_southern_ocean = ma.masked_values(cflux_southern_ocean,1e+20) # mask land nc.close() cflux = cflux_southern_ocean*1e08 # change units of data from mmol/m^2/s ### create an array that consists of the seasonal signal fro each pixel year_stack = np.split(cflux, 10, axis=0) year_stack = np.array(year_stack) signal_array = np.tile(np.mean(year_stack, axis=0), (10, 1, 1)) signal_array = ma.masked_where(signal_array > 1e20, signal_array) # need to mask ### average the array over latitude(or longitude) signal_time_lon = ma.mean(signal_array, axis=1) ### do a 2D Fourier Transform of the time/space image ft = np.fft.fft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log(mgft) log_mgft= np.log(mgft) Every second row of the ft consists completely of zeros. Why is this? Would it be acceptable to add a randomly small number to the signal to avoid this. signal_time_lon = signal_time_lon + np.random.randint(0,9,size=(730, 182))*1e-05 EDIT: Adding images and clarify meaning The output of rfft2 still appears to be a complex array. Using fftshift shifts the edges of the image to the centre; I still have a power spectrum regardless. I expect that the reason that I get rows of zeros is that I have re-created the timeseries for each pixel. The ft[0, 0] pixel contains the mean of the signal. So the ft[1, 0] corresponds to a sinusoid with one cycle over the entire signal in the rows of the starting image. Here are is the starting image using following code: plt.pcolormesh(signal_time_lon); plt.colorbar(); plt.axis('tight') Here is result using following code: ft = np.fft.rfft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log1p(mgft) plt.pcolormesh(log_ps); plt.colorbar(); plt.axis('tight') It may not be clear in the image but it is only every second row that contains completely zeros. Every tenth pixel (log_ps[10, 0]) is a high value. The other pixels (log_ps[2, 0], log_ps[4, 0] etc) have very low values.

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• java concurrency: many writers, one reader

  - by Janning

  I need to gather some statistics in my software and i am trying to make it fast and correct, which is not easy (for me!) first my code so far with two classes, a StatsService and a StatsHarvester public class StatsService { private Map<String, Long> stats = new HashMap<String, Long>(1000); public void notify ( String key ) { Long value = 1l; synchronized (stats) { if (stats.containsKey(key)) { value = stats.get(key) + 1; } stats.put(key, value); } } public Map<String, Long> getStats ( ) { Map<String, Long> copy; synchronized (stats) { copy = new HashMap<String, Long>(stats); stats.clear(); } return copy; } } this is my second class, a harvester which collects the stats from time to time and writes them to a database. public class StatsHarvester implements Runnable { private StatsService statsService; private Thread t; public void init ( ) { t = new Thread(this); t.start(); } public synchronized void run ( ) { while (true) { try { wait(5 * 60 * 1000); // 5 minutes collectAndSave(); } catch (InterruptedException e) { e.printStackTrace(); } } } private void collectAndSave ( ) { Map<String, Long> stats = statsService.getStats(); // do something like: // saveRecords(stats); } } At runtime it will have about 30 concurrent running threads each calling notify(key) about 100 times. Only one StatsHarvester is calling statsService.getStats() So i have many writers and only one reader. it would be nice to have accurate stats but i don't care if some records are lost on high concurrency. The reader should run every 5 Minutes or whatever is reasonable. Writing should be as fast as possible. Reading should be fast but if it locks for about 300ms every 5 minutes, its fine. I've read many docs (Java concurrency in practice, effective java and so on), but i have the strong feeling that i need your advice to get it right. I hope i stated my problem clear and short enough to get valuable help.

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• Windows 7: Search indexing is stuck

  - by Ricket

  When I open Indexing Options, it says: 4,317 items indexed Indexing in progress. Search results might not be complete during this time. It's stuck at 4,317 though; no more items have been indexed. Worst of all, SearchIndexer.exe is taking up 100% CPU (well, 50%, but I have a dual core CPU; it's taking up all processing power it can). It is not causing hard drive activity though. I tried clicking "Troubleshoot search and indexing" at the bottom of the Indexing Options window, but it couldn't find any problem. I've also tried the repair registry key that several websites suggest; I change HKLM\SOFTWARE\Microsoft\Windows Search SetupCompletedSuccessfully to 0 and restarted the computer, and it apparently repaired because it flipped back to 1, but the same problem continues to occur. It's reducing the battery life of my laptop and making it really hot so that my fans are running all the time. I've had to disable the Windows Search service. How can I fix this? Do I need to just flat-out reformat my computer? Update: I've tried rebuilding a couple times. There's nothing unusual about the locations I have to index, and I don't have any downloads in progress or anything like that. I don't see any reason why it stopped, and I noticed it much too late to do a system restore. At this point, I'm hoping someone will offer up some secret answer that will fix the problem, thus the bounty. Another update: I tried starting the service again, just to let it try yet again. It seemed okay at first (Indexing Options showed it operating at reduced speed due to user activity, and the number of files was going up). A while later I checked, and the service had stopped. Event viewer revealed some errors like this: Log Name: Application Source: Application Error Date: 2/1/2010 7:34:23 PM Event ID: 1000 Task Category: (100) Level: Error Keywords: Classic User: N/A Computer: ricky-win7 Description: Faulting application name: SearchIndexer.exe, version: 7.0.7600.16385, time stamp: 0x4a5bcdd0 Faulting module name: NLSData0007.dll, version: 6.1.7600.16385, time stamp: 0x4a5bda88 Exception code: 0xc0000005 Fault offset: 0x002141ba Faulting process id: 0x13a0 Faulting application start time: 0x01caa39f2a70ec02 Faulting application path: C:\Windows\system32\SearchIndexer.exe Faulting module path: C:\Windows\System32\NLSData0007.dll Report Id: b4f7a7ae-0f92-11df-87fc-e5d65d8794c2 Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Application Error" /> <EventID Qualifiers="0">1000</EventID> <Level>2</Level> <Task>100</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2010-02-02T00:34:23.000000000Z" /> <EventRecordID>10689</EventRecordID> <Channel>Application</Channel> <Computer>ricky-win7</Computer> <Security /> </System> <EventData> <Data>SearchIndexer.exe</Data> <Data>7.0.7600.16385</Data> <Data>4a5bcdd0</Data> <Data>NLSData0007.dll</Data> <Data>6.1.7600.16385</Data> <Data>4a5bda88</Data> <Data>c0000005</Data> <Data>002141ba</Data> <Data>13a0</Data> <Data>01caa39f2a70ec02</Data> <Data>C:\Windows\system32\SearchIndexer.exe</Data> <Data>C:\Windows\System32\NLSData0007.dll</Data> <Data>b4f7a7ae-0f92-11df-87fc-e5d65d8794c2</Data> </EventData> </Event> If you are having the same error and arrived here from a Google search, please comment or add an answer detailing your progress on this, if any...

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• Optimizing Python code with many attribute and dictionary lookups

  - by gotgenes

  I have written a program in Python which spends a large amount of time looking up attributes of objects and values from dictionary keys. I would like to know if there's any way I can optimize these lookup times, potentially with a C extension, to reduce the time of execution, or if I need to simply re-implement the program in a compiled language. The program implements some algorithms using a graph. It runs prohibitively slowly on our data sets, so I profiled the code with cProfile using a reduced data set that could actually complete. The vast majority of the time is being burned in one function, and specifically in two statements, generator expressions, within the function: The generator expression at line 202 is neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) and the generator expression at line 204 is neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) The source code for this function of context provided below. selected_nodes is a set of nodes in the interaction_graph, which is a NetworkX Graph instance. node_neighbors is an iterator from Graph.neighbors_iter(). Graph itself uses dictionaries for storing nodes and edges. Its Graph.node attribute is a dictionary which stores nodes and their attributes (e.g., 'weight') in dictionaries belonging to each node. Each of these lookups should be amortized constant time (i.e., O(1)), however, I am still paying a large penalty for the lookups. Is there some way which I can speed up these lookups (e.g., by writing parts of this as a C extension), or do I need to move the program to a compiled language? Below is the full source code for the function that provides the context; the vast majority of execution time is spent within this function. def calculate_node_z_prime( node, interaction_graph, selected_nodes ): """Calculates a z'-score for a given node. The z'-score is based on the z-scores (weights) of the neighbors of the given node, and proportional to the z-score (weight) of the given node. Specifically, we find the maximum z-score of all neighbors of the given node that are also members of the given set of selected nodes, multiply this z-score by the z-score of the given node, and return this value as the z'-score for the given node. If the given node has no neighbors in the interaction graph, the z'-score is defined as zero. Returns the z'-score as zero or a positive floating point value. :Parameters: - `node`: the node for which to compute the z-prime score - `interaction_graph`: graph containing the gene-gene or gene product-gene product interactions - `selected_nodes`: a `set` of nodes fitting some criterion of interest (e.g., annotated with a term of interest) """ node_neighbors = interaction_graph.neighbors_iter(node) neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) try: max_z_score = max(neighbor_z_scores) # max() throws a ValueError if its argument has no elements; in this # case, we need to set the max_z_score to zero except ValueError, e: # Check to make certain max() raised this error if 'max()' in e.args[0]: max_z_score = 0 else: raise e z_prime = interaction_graph.node[node]['weight'] * max_z_score return z_prime Here are the top couple of calls according to cProfiler, sorted by time. ncalls tottime percall cumtime percall filename:lineno(function) 156067701 352.313 0.000 642.072 0.000 bpln_contextual.py:204(<genexpr>) 156067701 289.759 0.000 289.759 0.000 bpln_contextual.py:202(<genexpr>) 13963893 174.047 0.000 816.119 0.000 {max} 13963885 69.804 0.000 936.754 0.000 bpln_contextual.py:171(calculate_node_z_prime) 7116883 61.982 0.000 61.982 0.000 {method 'update' of 'set' objects}

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• Recommended textbook for machine-level programming?

  - by Norman Ramsey

  I'm looking at textbooks for an undergraduate course in machine-level programming. If the perfect book existed, this is what it would look like: Uses examples written in C or assembly language, or both. Covers machine-level operations such as two's-complement integer arithmetic, bitwise operations, and floating-point arithmetic. Explains how caches work and how they affect performance. Explains machine instructions or assembly instructions. Bonus if the example assembly language includes x86; triple bonus if it includes x86-64 (aka AMD64). Explains how C values and data structures are represented using hardware registers and memory. Explains how C control structures are translated into assembly language using conditional and unconditional branch instructions. Explains something about procedure calling conventions and how procedure calls are implemented at the machine level. Books I might be interested in would probably have the words "machine organization" or "computer architecture" in the title. Here are some books I'm considering but am not quite happy with: Computer Systems: A Programmer's Perspective by Randy Bryant and Dave O'Hallaron. This is quite a nice book, but it's a book for a broad, shallow course in systems programming, and it contains a great deal of material my students don't need. Also, it is just out in a second edition, which will make it expensive. Computer Organization and Design: The Hardware/Software Interface by Dave Patterson and John Hennessy. This is also a very nice book, but it contains way more information about how the hardware works than my students need. Also, the exercises look boring. Finally, it has a show-stopping bug: it is based very heavily on MIPS hardware and the use of a MIPS simulator. My students need to learn how to use DDD, and I can't see getting this to work on a simulator. Not to mention that I can't see them cross-compiling their code for the simulator, and so on and so forth. Another flaw is that the book mentions the x86 architecture only to sneer at it. I am entirely sympathetic to this point of view, but news flash! You guys lost! Write Great Code Vol I: Understanding the Machine by Randall Hyde. I haven't evaluated this book as thoroughly as the other two. It has a lot of what I need, but the translation from high-level language to assembler is deferred to Volume Two, which has mixed reviews. My students will be annoyed if I make them buy a two-volume series, even if the price of those two volumes is smaller than the price of other books. I would really welcome other suggestions of books that would help students in a class where they are to learn how C-language data structures and code are translated to machine-level data structures and code and where they learn how to think about performance, with an emphasis on the cache.

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