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What is the exact difference between MEM_RESERVE and MEM_COMMIT states?

- by pj4533

As I understand it MEM_RESERVE is actually 'free' memory, ie available to be used by my process, but just hasn't been allocated yet? Or it was previously allocated, but had since been freed? Specifically, see in my !address output below how I am nearly out of virtual address space (99900 KB free, 2307872 as MEM_PRIVATE. But the states shows that 44.75% of that is actually MEM_RESERVE. Does that mean it is actually free, in my process...but maybe fragmented? 0:000> !address -summary --------- PEB a8bd8000 not found ---- -------------------- Usage SUMMARY -------------------------- TotSize ( KB) Pct(Tots) Pct(Busy) Usage 259af000 ( 616124) : 22.29% 23.12% : RegionUsageIsVAD 618f000 ( 99900) : 03.61% 00.00% : RegionUsageFree 13e22000 ( 325768) : 11.78% 12.22% : RegionUsageImage 42c04000 ( 1093648) : 39.56% 41.04% : RegionUsageStack 42d000 ( 4276) : 00.15% 00.16% : RegionUsageTeb 2625d000 ( 625012) : 22.61% 23.45% : RegionUsageHeap 0 ( 0) : 00.00% 00.00% : RegionUsagePageHeap 0 ( 0) : 00.00% 00.00% : RegionUsagePeb 1000 ( 4) : 00.00% 00.00% : RegionUsageProcessParametrs 1000 ( 4) : 00.00% 00.00% : RegionUsageEnvironmentBlock Tot: a8bf0000 (2764736 KB) Busy: a2a61000 (2664836 KB) -------------------- Type SUMMARY -------------------------- TotSize ( KB) Pct(Tots) Usage 618f000 ( 99900) : 03.61% : <free> 13e22000 ( 325768) : 11.78% : MEM_IMAGE 1e77000 ( 31196) : 01.13% : MEM_MAPPED 8cdc8000 ( 2307872) : 83.48% : MEM_PRIVATE -------------------- State SUMMARY -------------------------- TotSize ( KB) Pct(Tots) Usage 57235000 ( 1427668) : 51.64% : MEM_COMMIT 618f000 ( 99900) : 03.61% : MEM_FREE 4b82c000 ( 1237168) : 44.75% : MEM_RESERVE Largest free region: Base 7e4a1000 - Size 000ff000 (1020 KB)

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Are local variables in Fortran 77 static or stack dynamic?

- by mm2887

For my programming languages class one hw problem asks: Are local variables in FORTRAN static or stack dynamic? Are local variables that are INITIALIZED to a default value static or stack dynamic? Show me some code with an explanation to back up your answer. Hint: The easiest way to check this is to have your program test the history sensitivity of a subprogram. Look at what happens when you initialize the local variable to a value and when you don’t. You may need to call more than one subprogram to lock in your answer with confidence. I wrote a few subroutines: - create a variable - print the variable - initialize the variable to a value - print the variable again Each successive call to the subroutine prints out the same random value for the variable when it is uninitialized and then it prints out the initialized value. What is this random value when the variable is uninitialized? Does this mean Fortran uses the same memory location for each call to the subroutine or it dynamically creates space and initializes the variable randomly? My second subroutine also creates a variable, but then calls the first subroutine. The result is the same except the random number printed of the uninitialized variable is different. I am very confused. Please help! Thank you so much.

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Why does my Perl CGI script complain about "Can't locate CGI/Simple.pm"?

- by dexter

For more information see this Example use strict; use warnings; use CGI::Simple; use DBI; my $cgi = CGI::Simple->new; my $dsn = sprintf( 'DBI:mysql:database=%s;host=%s', 'cdcol', 'localhost' ); my $dbh = DBI->connect($dsn, root => '', { AutoCommit => 0, RaiseError => 0 } ); my $status = $dbh ? 'Connected' : 'Failed to connect'; print $cgi->header, <<HTML; <!DOCTYPE HTML> <html> <head><title>Test</title></head> <body> <h1>Perl CGI Script</h1> <p>$status</p> </body> </html> HTML This code gives me error: The server encountered an internal error and was unable to complete your request. Error message: Can't locate CGI/Simple.pm in @INC (@INC contains: C:/xampp/perl/site/lib/ C:/xampp/perl/lib C:/xampp/perl/site/lib C:/xampp/apache) at C:/xampp/htdocs/perl/index.pl line 4. BEGIN failed--compilation aborted at C:/xampp/htdocs/perl/index.pl line 4. , Error 500 localhost 3/25/2010 11:19:19 AM Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 What does this mean and how can I resolve it?

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Spring maven libraries

- by Calm Storm

I would like to know why some of the libraries are not released during a normal release cycle. For example, from http://repo2.maven.org/maven2/org/springframework/ while spring-core have 3.0.3-RELEASE, spring-remoting and spring-jmx were released only in 2.0.8. Can someone tell me what this would mean? I agree that if there are no changes in the component say spring-jmx then they don't have to release it, but since 90% of the world uses Maven for dependency management can they not just re-release the same libs (of spring-remoting and spring-jmx?) I ask this because I declare my deps like, <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-remoting</artifactId> <version>${spring.version}</version> </dependency> and I would prefer supplying one spring.version instead of keeping version numbers upto date for all components? The four libraries of interest to me are spring-dao, spring-support, spring-jmx, spring-remoting

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Tokyo Cabinet Tuning Parameters

- by user235478

Hello, I have been trying to find a better Tokyo Cabinet (or Tokyo Tyrant) configuration for my application, but I don't know exactly how. I know what some parameters mean but I want to have a fine tuning control, so I need to know the impact of each one. The Tokyo documentation is really good but not at this point. Does any one can help me? Thanks. TCHDB -> *bool tchdbtune(TCHDB *hdb, int64_t bnum, int8_t apow, int8_t fpow, uint8_t opts);* How do I use: bnum, apow and fpow? TCBDB -> *bool tcbdbtune(TCBDB *bdb, int32_t lmemb, int32_t nmemb, int64_t bnum, int8_t apow, int8_t fpow, uint8_t opts);* How do I use: lmemb, nmemb, bnum, apow and fpow? TCFDB -> *bool tcfdbtune(TCFDB *fdb, int32_t width, int64_t limsiz);* How do I use: width and limsiz? Note: I am only putting this to get all types of database in the topic, this one is really simple. TCTDB -> *bool tctdbtune(TCTDB *tdb, int64_t bnum, int8_t apow, int8_t fpow, uint8_t opts);* How do I use: bnum, apow and fpow?

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asynchronous pages

- by lockedscope

I have just read the multi-threading and custom threading in asp.net articles. http://www.williablog.net/williablog/post/2008/12/16/Custom-Threading-in-ASPNET.aspx http://www.williablog.net/williablog/post/2008/12/16/Multi-Threading-in-ASPNET.aspx I have couple of questions. What does he mean by returning a thread to the pool? Is that thread completely removed from memory or put in to a state that it does not scheduled to CPU(is it in sleep state or whatever)? If that thread is removed from memory how could it survive after async point? How this mechanism works? Are every objects(pages class, request,response etc.) are copied to somewhere else before they are disposed? (Or, is it just waiting in a sleep state and then its waked when async call ends?) He is saying that; "Having said that, making pages asynchronous is not really about improving performance, it is about improving scalability" then he is saying; "I'm sorry to say that it will do nothing for scalability or performance." So which one is true? or for which case(s) are they true?

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.NET CF -- Set Form height based on InputPanel state

- by user354941

Hi, So, I've got a C# project for Windows Mobile phones and I'm trying to work with the InputPanel. Specifically, I've got one form with a stack of Labels and TextBoxes that collect user input. I have an InputPanel that alerts me when the user opens the SIP. Everything works fine so far. When I get messages that the SIP status has changed, I want to change the height of the Form, which doesn't seem possible. Here's my event handler for my InputPanel: void m_InputPanel_EnabledChanged(object sender, EventArgs e) { // :( this assignment operation doesn't work and it doesn't this.ClientSize = inputPanel1.VisibleDesktop.Size; // doesn't work this.Size = inputPanel1.VisibleDesktop.Size; // assignment operation works, but isn't very useful this.visibleHeight = inputPanel1.VisibleDesktop.Height; this.InitializeUI(); } When I say that the assignment operation doesn't work, I mean that the values don't change in the debugger. I can understand that maybe I can't change the size of a Form, but I can't understand why trying to change it wouldn't throw an exception, or give a compiler error. I have my Form WindowState set to Normal instead of Maximized, but it doesn't make a difference. Also, I have read http://www.christec.co.nz/blog/archives/42 this page that tells me how I'm supposed to do this, but I can't easily put all of my controls in a Panel because I'm using a bunch of custom stuff to do alpha background controls.

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Selenium and Firefox 9's "Will you help improve Mozilla Firefox" popup

- by Rup

I'm trying to test a Java web app using Selenium 2.16.1. When Selenium opens Firefox, I see a band at the top of the page with message "Will you help improve Mozilla Firefox" For some reason this breaks selenium.click("id=submit"); selenium.waitForPageToLoad("60000"); which is trying to log in - it becomes a no-op, and the test fails because it's then expecting to have logged in. If I break on the click line and clear the 'will you help' band before continuing then the form submit succeeds. Is there a way to suppress this band from appearing? (I expect that would mean setting a property in Firefox's default profile - where do I find that?) Or is there a way to get Selenium to spot and dismiss this first? Thanks! I'm using Firefox 9.0.1. Solved - thanks Danny! Just in case it isn't clear from the answers and comments below: This was an issue with 2.16.1 and IMO the best solution is to upgrade to 2.17 or later.

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Distributed development systems

- by Nathan Adams

I am interested in a system that allows for distributed development with an authentication piece. What do I mean by that? Ok so lets take SVN, SVN keeps track of revisions and doesn't care who submits, as long as you have the right to submit you can submit, really, to any part in the repository. Where does my system come into play? Being able to granulate access control and give a stackoverflow like feel to the environment. In the system I am describing we have 4 users Bob, Alice, Dan, Joe. Bob is a project managed, Alice and Dan are programmers under Bob and Joe is a random programmer on the internet who wants to help. Ideally in this system, Bob can commit any changes and won't require approval. Alice and Dan can commit to their branches, or a branch, but a commit to the trunk would need approval by Bob. This is where Joe comes in, wants to help, however, you just don't want to give him the keys to the kingdom just yet so to speak, so in my system you would setup a "low user" account. Any commits that Joe makes would need to be approved by Dan, Alice or both. However, in the system, Joe can build up "Karma" where after so many approved commits it would only need approval by one of the programmers, and then eventually no approval would be necessary. Does that make sense and do you know if a system like that exists? Or am I just crazy to even think such a system/environment would be possible?

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Writing a JMS Publisher without "public static void main"

- by The Elite Gentleman

Hi guys, Every example I've seen on the web, e.g. http://www.codeproject.com/KB/docview/jms_to_jms_bridge_activem.aspx, creates a publisher and subscriber with a public static void main method. I don't think that'll work for my web application. I'm learning JMS and I've setup Apache ActiveMQ to run on JBoss 5 and Tomcat 6 (with no glitches). I'm writing a messaging JMS service that needs to send email asynchronously. I've already written a JMS subscriber that receives the message (the class inherits MessageListener). My question is simple: How do I write a publisher that will so that my web applications can call it? Does it have to be published somewhere? My thought is to create a publisher with a no-attribute constructor (in there) and get the MessageQueue Factory, etc. from the JNDI pool (in the constructor). Is my idea correct? How do I subscribe my subscriber to the Queue Receiver? (So far, the subscriber has no constructor, and if I write a constructor, do I always subscribe myself to the Queue receiver?) Thanks for your help, sorry if my terminology is not up to scratch, there are too many java terminologies that I get lost sometimes (maybe a java GPS will do! :-) ) PS Is there a tutorial out there that explains how to write a "better" (better can mean anything, but in my case it's all about performance in high demand requests) JMS Publisher and Subscriber that I can run on Application Server such as JBoss or Glassfish? Don't forget that the JMS application will needs a "guarantee" uptime as many applications will use this.

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Workflow UI Integration - is WF a good approach?

- by AJ

Somewhat similar to this question, except we haven't decided that we're going with WF yet. I'm working on designing a system that requires a series of decisions and activities on a "work object," so I naturally began to consider workflow, specifically WF. What I'm wondering is if WF is a good solution for a situation like the following (oversimplified for this question) case (please forgive bad ascii art): __________________ | Gather some info | | (web page) | |__________________| | | / \ / \ / \ / \ / cond \ \ 1 / \ / \ / \ / \ / | | ______________|_______________ | | | | | ______|______ ______|________ / do some / | Get more info | / process / | (web page) | /____________/ |_______________| | | / \ / \ / \ / cond. \ \ 2 / \ / \ / \ / | | |__________________ | | | | _____|_____ _____|_____ / some / / another / / process / / process / /__________/ /__________/ The part I'm struggling with is the get more info (web page) step and what happens subsequent, which would mean a halt in the execution of the workflow runtime. I'm aware that this is possible, but I'm not sure that WF is the best approach for this type of code, as the user interaction may be required at many different points through the entire workflow, and the workflow will drive what data entry screens are needed. We are using a WinForms/ASP.NET web forms package for UI, which is homegrown and difficult to push deployments on, so something like SharePoint integration is out of the question. Our back-end is DB2, and the workflow code (whether it's in WF or otherwise) will need to interact with that as well. I guess the bottom line is, should we look into using WF for this, or would we be better served just coding it ourselves? Can WF easily integrate data entry screens to capture information that can be used further on in the workflow?

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PHP - Database schema: version control, branching, migrations.

- by Billiam

I'm trying to come up with (or find) a reusable system for database schema versioning in php projects. There are a number of Rails-style migration projects available for php. http://code.google.com/p/mysql-php-migrations/ is a good example. It uses timestamps for migration files, which helps with conflicts between branches. General problem with this kind of system: When development branch A is checked out, and you want to check out branch B instead, B may have new migration files. This is fine, migrating to newer content is straight forward. If branch A has newer migration files, you would need to migrate downwards to the nearest shared patch. If branch A and B have significantly different code bases, you may have to migrate down even further. This may mean: Check out B, determine shared patch number, check out A, migrate downwards to this patch. This must be done from A since the actual applied patches are not available in B. Then, checkout branch B, and migrate to newest B patch. Reverse process again when going from B to A. Proposed system: When migrating upwards, instead of just storing the patch version, serialize the whole patch in database for later use, though I'd probably only need the down() method. When changing branches, compare patches that have been run to patches that are available in the destination branch. Determine nearest shared patch (or oldest difference, maybe) between db table of run patches and patches in destination branch by ID or hash. Could also look for new or missing patches that are buried under a number of shared patches between the two branches. Automatically merge down to the nearest shared patch, using the db table stored down() methods, and then merge up to the branche's latest patch. My question is: Is this system too crazy and/or fraught with consequences to bother developing? My experience with database schema versioning is limited to PHP autopatch, which is an up()-only system requiring filenames with sequential IDs.

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Why Finalize method not allowed to override

- by somaraj

I am new to .net ..and i am confused with the destructor mechanism in C# ..please clarify In C# destructors are converted to finalize method by CLR. If we try to override it (not using destructor ) , will get an error Error 2 Do not override object.Finalize. Instead, provide a destructor. But it seems that the Object calss implementation in mscorlib.dll has finalize defined as protected override void Finalize(){} , then why cant we override it , that what virtual function for . Why is the design like that , is it to be consistent with c++ destructor concept. Also when we go to the definition of the object class , there is no mention of the finalize method , then how does the hmscorlib.dll definition shows the finalize funtion . Does it mean that the default destructor is converted to finalize method. public class Object { public Object(); public virtual bool Equals(object obj); public static bool Equals(object objA, object objB); public virtual int GetHashCode(); public Type GetType(); protected object MemberwiseClone(); public static bool ReferenceEquals(object objA, object objB); public virtual string ToString(); }

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how to verify browser IP for server-side web service

- by Anthony

I have a web service that needs to be able to verify the end-user's IP that called the server-script that is requesting the web service. Simple layout: Person A goes to Webpage B. Webpage B calls Web Service C to get some info on Person A. Web Service C won't give Webpage B the requested information without confirmation that the request originated from Person A's IP and not someone who has stolen Person A's session. I'm thinking that for a browser-based solution, the original site (Webpage B) can open an iframe that goes to the Web Service's authentication page. A key of some kind is passed to the browser which will some how indicate both the user's IP and Web Page B's IP, so that the Web Service can confirm that no one has nabbed anything. I have two challenges, but I'll stick to the more immediate one first: I'm not sure if my browser-based plan really makes sense. If someone steals the session cookie, how is the Web Service going to know? Would this cookie be held be Web Page B and thus be harder to steal? Is it a sound assumption that a cookie or key held by the server only and not the browser is safe? Also, would the web service, based on the iframe initial connection, be expecting the server/user-ip combo? What I mean is, does the session key provided via the iframe get stored by the web service and the Web Site B shows it has a match? Or is the session key more generic, meaning the web service is passed the key by Website B and the Web Service verifies that this is a valid session key based on what a valid session key should look like?

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JVM terminates when launching eclipse with J2SE 6.0 on mac os x (need J2SE 6.0 for Oracle enterprise

- by rooban bajwa

I know my issue has party been addressed at this link http://stackoverflow.com/questions/245803/jvm-terminates-when-launching-eclipse-mat-on-mac-os-with-j2se-60 but it was a year+ ago.. plus the link that's provided in there http://landonf.bikemonkey.org/static/soylatte/ does not seem to be alive (i mean the download section on that link no longer provide the 32-bit port of j2se 6.0 for mac osx 10.5) I am trying to run eclipse 3.5 on mac OSX 10.5. It works fine with J2SE 5.0. But when I installed the Oracle enterprise pack for eclipse - it requires to start eclipse with J2SE 6.0 JVM otherwise it will get disabled. Here's the exact message I get from it - "You are running Eclipse on Java VM version: 1.5.0_22 Oracle Enterprise Pack for Eclipse requires Java version 6 or higher. Click next to configure a compatible Java VM." It asks me to point to J2SE 6.0 JVM, when I do that (i.e point it to "/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home") , it asks to restart eclipse , when I do that, eclipse just bombs .. with JVM terminated error .. SO I need to start eclipse with J2SE 6.0 JVM but eclipse needs carbon which is only available in 32 bits and hence I cann't start eclipse with J2SE 6.0 JVM which is only available in 64bit mode from mac. And the site providing 32 bit port of J2SE 6.0 JVM does not seem to be active anymore.. Can someone help me on this issue, Thanks in advance,

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Resizing video best practices (frame size)

- by undefined

I have read the following which is from Best Practices for Encoding Video with the VP6 Codec on the Adobe website here - http://www.adobe.com/devnet/flash/articles/encoding_video_print.html. It is talking about common video ratios (320x240, 640x480) Although these ratios are standard, and should be used to avoid distorting the video, the size of the encoded video is not set in stone. The original web video sizes used heights and widths that were evenly divisible by 16. This was mandatory for many early codecs. Although this is not necessary for modern codecs, you should stick to even heights and widths. What do they mean by 'even heights and widths'. I am thinking about encoding my video at 400x300 to make it slightly bigger, this is still 4x3 format but should I just stick at 320x240 and resize it on the screen? Clearly there are benefits to this in terms of storage size and delivery costs. In some places on my site I want to show the video at 400x300 but in others I want it to play full screen so this is why I am wondering if a larger original size (400x300) will give better results when blown up. Any thoughts?

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Explaining verity index and document search limits

- by Ahmad

As present, we currently have a CF8 standard edition server which have some limitations around verity indexing. According to Adobe Verity Server has the following document search limits (limits are for all collections registered to Verity Server): - 10,000 documents for ColdFusion Developer Edition - 125,000 documents for ColdFusion Standard Edition - 250,000 documents for ColdFusion Enterprise Edition We have now reached a stage where the server wide number of documents indexed exceed 125k. However, the largest verity collection consists of about 25k documents(and this is expected to grow). Only one collection is ever searched at a time. In my understanding, this means that I can still search an entire collection with no restrictions. Is this correct? Or does it mean that only documents that were indexed across all collection prior to reaching the limit are actually searchable? We are considering moving to CF9 standard as a solution to this and to use the Solr solution which has no restrictions. The coldfusionjedi highlights some differences between Verity and Solr. However, before we upgrade I am trying to gain a clearer understanding of this before we commit to an upgrade. Can someone provide me a clear explanation as to what this means and how it actually affects verity searching and indexing?

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Backing up my locally hosted rails apps in preparation for OS upgrade

- by stephen murdoch

I have some apps running on Heroku. I will be upgrading my OS in two weeks. The last time I upgraded though (6 months ago) I ran into some problems. Here's what I did: copied all my rails apps onto DVD upgraded OS transferred rails apps from DVD to new OS Then, after setting up new SSH-keys I tried to push to some of my heroku apps and, whilst I can't remember the exact error message off-hand, it more or less amounted to "fatal exception the remote end hung up" So I know that I'm doing something wrong here. First of all, is there any need for me to be putting my heroku hosted rails apps onto DVD? Would I be better just pulling all my apps from their heroku repos once I've done the upgrade? What do others do here? The reason I stuck them on DVD is because I tend to push a specific production branch to Heroku and sometimes omit large development files from it... Secondly, was this problem caused by SSH keys? Should I have backed up the old keys and transferred them from my old OS to my new one too, or is Heroku perfectly happy to let you change OS's like that? My solution in the end was to just create new heroku apps and reassign the custom domain names in heroku add-ons menu... I never actually though of pulling from the heroku repos as I tend to push a specific branch to heroku and that branch doesn't always have all the development files in it... I realise that the error message I mentioned doesn't particularly help anyone but I didn't think to remember it 6 months ago. Any advice would be appreciated PS - when I say upgrade, I mean full install of the new version with full format of the HDD.

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ActionScript 3.0: placing code on stage/MC timelines a la AS2 instead of in classes

- by BoltClock

I'm aware that ActionScript 3.0 is designed from the ground up to be a largely object-oriented language and using it means less or even no timeline code in Flash documents. I'm quite experienced with OOP and am comfortable writing classes. However, since I mostly use Flash for animations, I hardly ever need to write ActionScript code other than for preloaders, subtitles, quality controls, website links and so on. In fact, I still set my Flash movies to use AS2 to this day because I'm used to gotoAndPlay()/gotoAndStop(), AS2 preloaders, subtitles, quality controls and even getURL(). Of course, I really want to move on now that practically everyone's on Flash Player 9 or 10 and now that I've dabbled with other OO languages like Java, C# and Objective-C too. I'm a complete newcomer to AS3 and am not very learned with AS2 either. Considering my current use of ActionScript, are there any cases where it's still OK to use very simple AS3 code in the timeline instead of moving code to a class, especially since moving to a class might mean unnecessarily increasing the number of LOC from 4 to 40? (Heck, is the latter case ('instead of ...') even a valid concern at all?)

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[Haskell] Problem when mixing type classes and type families

- by Giuseppe Maggiore

Hi! This code compiles fine: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances, FlexibleContexts, EmptyDataDecls, ScopedTypeVariables, TypeOperators, TypeSynonymInstances, TypeFamilies #-} class Sel a s b where type Res a s b :: * instance Sel a s b where type Res a s b = (s -> (b,s)) instance Sel a s (b->(c,a)) where type Res a s (b->(c,a)) = (b -> s -> (c,s)) but as soon as I add the R predicate ghc fails: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances, FlexibleContexts, EmptyDataDecls, ScopedTypeVariables, TypeOperators, TypeSynonymInstances, TypeFamilies #-} class Sel a s b where type Res a s b :: * instance Sel a s b where type Res a s b = (s -> (b,s)) class R a where type Rec a :: * cons :: a -> Rec a elim :: Rec a -> a instance Sel a s (b->(c,Rec a)) where type Res a s (b->(c,Rec a)) = (b -> s -> (c,s)) complaining that: Illegal type synonym family application in instance: b -> (c, Rec a) In the instance declaration for `Sel a s (b -> (c, Rec a))' what does it mean and (most importantly) how do I fix it? Thanks

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Transitive SQL query on same table

- by MiKu

Hey. consider d following table and data... in_timestamp | out_timestamp | name | in_id | out_id | in_server | out_server | status timestamp1 | timestamp2 | data1 |id1 | id2 | others-server1 | my-server1 | success timestamp2 | timestamp3 | data1 | id2 | id3 | my-server1 | my-server2 | success timestamp3 | timestamp4 | data1 | id3 | id4 | my-server2 | my-server3 | success timestamp4 | timestamp5 | data1 | id4 | id5 | my-server3 | others-server2 | success the above data represent log of a execution flow of some data across servers. e.g. some data has flowed from some 'outside-server1' to bunch of 'my-servers' and finally to destined 'others-server2'. Question : 1) I need to give this log in representable form to client where he doesn't need to know anything about the bunch of 'my-servers'. All i am supposed to give is timestamp of the data entered my infrastructure and when it left; drilling down to following info. in_timestamp (of 'others_server1' to 'my-server1') out_timestamp (of 'my-server3' to 'others-server2') name status I want to write sql for the same! Can someone help? NOTE : there might not be 3 'my-servers' all the time. It differs from situation to situation. e.g. there might be 4 'my-server' involved for, say, data2! 2) Are there any other alternatives to SQL? I mean stored procs/etc? 3) Optimizations? (The records are huge in number! As of now, it is around 5 million a day. And we are supposed to show records that are upto a week old.) In advance, THANKS FOR THE HELP! :)

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Calling ASP.NET Web API using JQuery ajax - cross site scripting issue

- by SimonF

I have a Web API which I am calling using the JQuery ajax function. When I test the service directly (using the Chrome RESTEasy extension) it works fine, however when I call it using the JQuery ajax function I get an error. I'm calling it on port 81: $.ajax({ url: "http://127.0.0.1:81/api/people", data: JSON.stringify(personToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newPerson) { callback(newPerson); } }, success: function (newPerson) { alert("New person created with an Id of " + newPerson.Id); }, error: function (jqXHR, textStatus, errorThrown) { alert('Error. '+textStatus+'. '+errorThrown); } }); ...but when I trace it using FireBug Lite the response comes from port 82: {"Message":"No HTTP resource was found that matches the request URI 'http://127.0.0.1:82/api/people'.","MessageDetail":"No action was found on the controller 'People' that matches the request."} I think the error is, effectively, due to cross-site scripting being blocked, but I'm not actually cross-site scripting, if you see what I mean. Has anyone else come across this and been able to fix it? Edit: Routing config (global.asax.vb) is: RouteTable.Routes.MapHttpRoute(name:="DefaultApi", routeTemplate:="api/{controller}/{id}", defaults:=New With {Key .id = System.Web.Http.RouteParameter.Optional}) Controller: Public Function PostValue(ByVal departmentid As Integer, ByVal emailaddress As String, ByVal firstname As String, ByVal lastname As String) As Guid Dim context As New WSMModelDataContext Dim bllPeople As New PeopleBLL(context) Return bllPeople.Create(firstname, lastname, emailaddress, departmentid) End Function When I debug it, it doesn't get as far as running the controller, although when calling it through RESTEasy it routes correctly and the controller executes successfully. The only difference seemes to be that wen called through RESTEasy it is (correctly) using http://127.0.0.1:81 but for some reason when called via JQuery/ajax it seems to be using http://127.0.0.1:82.

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What should every developer know about databases?

- by Aaronaught

Whether we like it or not, many if not most of us developers either regularly work with databases or may have to work with one someday. And considering the amount of misuse and abuse in the wild, and the volume of database-related questions that come up every day, it's fair to say that there are certain concepts that developers should know - even if they don't design or work with databases today. So: What are the important concepts that developers and other software professionals ought to know about databases? Guidelines for Responses: Keep your list short. One concept per answer is best. Be specific. "Data modelling" may be an important skill, but what does that mean precisely? Explain your rationale. Why is your concept important? Don't just say "use indexes." Don't fall into "best practices." Convince your audience to go learn more. Upvote answers you agree with. Read other people's answers first. One high-ranked answer is a more effective statement than two low-ranked ones. If you have more to add, either add a comment or reference the original. Don't downvote something just because it doesn't apply to you personally. We all work in different domains. The objective here is to provide direction for database novices to gain a well-founded, well-rounded understanding of database design and database-driven development, not to compete for the title of most-important.

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Are Large iPhone Ping Times Indicative of Application Latency?

- by yar

I am contemplating creating a realtime app where an iPod Touch/iPhone/iPad talks to a server-side component (which produces MIDI, and sends it onward within the host). When I ping my iPod Touch on Wifi I get huge latency (and a enormous variance, too): 64 bytes from 192.168.1.3: icmp_seq=9 ttl=64 time=38.616 ms 64 bytes from 192.168.1.3: icmp_seq=10 ttl=64 time=61.795 ms 64 bytes from 192.168.1.3: icmp_seq=11 ttl=64 time=85.162 ms 64 bytes from 192.168.1.3: icmp_seq=12 ttl=64 time=109.956 ms 64 bytes from 192.168.1.3: icmp_seq=13 ttl=64 time=31.452 ms 64 bytes from 192.168.1.3: icmp_seq=14 ttl=64 time=55.187 ms 64 bytes from 192.168.1.3: icmp_seq=15 ttl=64 time=78.531 ms 64 bytes from 192.168.1.3: icmp_seq=16 ttl=64 time=102.342 ms 64 bytes from 192.168.1.3: icmp_seq=17 ttl=64 time=25.249 ms Even if this is double what the iPhone-Host or Host-iPhone time would be, 15ms+ is too long for the app I'm considering. Is there any faster way around this (e.g., USB cable)? If not, would building the app on Android offer any other options? Traceroute reports more workable times: traceroute to 192.168.1.3 (192.168.1.3), 64 hops max, 52 byte packets 1 192.168.1.3 (192.168.1.3) 4.662 ms 3.182 ms 3.034 ms can anyone decipher this difference between ping and traceroute for me, and what they might mean for an application that needs to talk to (and from) a host?

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nginx with passenger

- by Luc

Hello, I'm trying to move from Apache + Passenger to Nginx + passenger on my Ubuntu Lucid Lynx box. When I install passenger, sudo gem install passenger and cd /var/lib/gems/1.9.1/gems/passenger-2.2.14/bin sudo ./passenger-install-nginx-module everything is fine (no error). Nginx is downloaded / compiled and installed at the same time (when selecting the first option during passenger installation). By default it is installed in /opt/nginx. I end up with the configuration file /opt/nginx/conf/nginx.conf (this conf file was automatically updated with passenger config). The thing I do not understand is that I also have the configuration file /etc/nginx/nginx.conf... what is the purpose of this one when it seems that the conf file in /opt/... is the main one ? When I run /etc/init.d/nginx start, it starts correclty saying that /etc/nginx/nginx.conf is ok... Does it mean that it does not check the other conf file ? I have updated /etc/init.d/nginx script and add /opt/nginx/sbin at the beginning of the PATH and it seems the correct conf file is taken into account. It seems like I have 2 nginx installations where I only relied on passenger to install it... Thanks a lot for your help, I am kind of lost here :) Luc

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