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  • How is management of requirements for embedded software different from business applications ?

    - by Chakra
    For business software we usually document the business flow and functional and non functional specs as SRS, Use cases or user stories. One of the critical requirements is UI design which may get prototyped. How do people in the real world document and manage requirements for embedded software for automobile systems ? How are they different from the business applications in terms of requirements management ? Thanks, Chak.

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  • Are there any lightweight analogues to CORBA/RPC for embedded programs?

    - by Mtr
    I am writing embedded applications for different hardware (avr, arm7, tms55xx…) and different rtoses (freeRTOS, rtx, dsp/bios). And every second of them needs to communicate with PC or another digital device. Sometimes interactions logic is very advanced. So I'm interesting in common methodology (like state-machine programming style), protocol specification or library, that could simplify developing such things.

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  • Is Perl still a useful, viable language?

    - by Bob
    I know it may have been asked before, but here goes nothing... Is Perl still something that would be considered useful? If someone was a new programmer (either completely new to programming or just a few month/years of experience) would Perl be something to be considered worthwhile to learn? Is Perl still used with frequency? Is it still popular? Or is Perl dying out compared to languages like Python, Ruby, PHP, ASP, .NET, etc.? Basically it boils down to this: Is it still used/is it still used frequently? If yes, is it dying? If no, will it make a come back? Is it something that would be worth learning? How does it compare in demand to languages like Python in both popularity and usability/viability? Could languages like Python or Ruby be considered replacements for Perl? Also, will newer versions of Perl really bring a large improvement to the Perl community, and perhaps bring Perl back to centerstage compared to other languages? EDIT: Okay, I suppose here's a better, reworded question: Is Perl still growing, or is it "dying"? Is it still a language worth learning and using? What projects does it really "shine" in compared to other languages? What makes Perl a language to choose? Essentially: is Perl growing obsolete compared to other languages, and if so, do you expect that to change, or to continue? And thank you to everyone who has answered so far, the discussion has been really interesting!

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  • Newbie, deciding Python or Erlang

    - by Joe
    Hi Guys, I'm a Administrator (unix, Linux and some windows apps such as Exchange) by experience and have never worked on any programming language besides C# and scripting on Bash and lately on powershell. I'm starting out as a service provider and using multiple network/server monitoring tools based on open source (nagios, opennms etc) in order to monitor them. At this moment, being inspired by a design that I came up with, to do more than what is available with the open source at this time, I would like to start programming and test some of these ideas. The requirement is that a server software that captures a stream of data and store them in a database(CouchDB or MongoDB preferably) and the client side (agent installed on a server) would be sending this stream of data on a schedule of every 10 minutes or so. For these two core ideas, I have been reading about Python and Erlang besides ruby. I do plan to use either Amazon or Rackspace where the server platform would run. This gives me the scalability needed when we have more customers with many servers. For that reason alone, I thought Erlang was a better fit(I could be totally wrong, new to this game) and I understand that Erlang has limited support in some ways compared to Ruby or Python. But also I'm totally new to the programming realm of things and any advise would be appreciated grately. Jo

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  • How relevant is UTF-7 when it comes to parsing emails?

    - by J. Pablo Fernández
    I recently implemented incoming emails for an application and boy, did I open the gates of hell? Since then every other day an email arrives that makes the app fail in a different way. One of those things is emails encoded as UTF-7. Most emails come as ASCII, some of the Latin encodings, or thankfully, UTF-8. Hotmail error messages (like email address doesn't exist or quota exceeded) seem to come as UTF-7. Unfortunately, UTF-7 is not an encoding Ruby understands: > "hello world".encode("utf-8", "utf-7") Encoding::ConverterNotFoundError: code converter not found (UTF-7 to UTF-8) > Encoding::UTF_7 => #<Encoding:UTF-7 (dummy)> My application doesn't crash, it actually handles the email quite well, but it does send me a notification about the potential error. I spent some time googling and I can't find anyone that implemented the conversion, at least not as a Ruby 1.9.3 Encoding::Converter. So, my question is, since I never got an email with actual content, from an actual person, in UTF-7, how relevant is that encoding? can I safely ignore it?

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  • How can I rank teams based off of head to head wins/losses

    - by TMP
    I'm trying to write an algorithm (specifically in Ruby) that will rank teams based on their record against each other. If a team A and team B have won the same amount of games against each other, then it goes down to point differentials. Here's an example: A beat B two times B beats C one time A beats D three times C bests D two times D beats C one time B beats A one time Which sort of reduces to A[B] = 2 B[C] = 1 A[D] = 3 C[D] = 2 D[C] = 1 B[A] = 1 Which sort of reduces to A[B] = 1 B[C] = 1 A[D] = 3 C[D] = 1 D[C] = -1 B[A] = -1 Which is about how far I've got I think the results of this specific algorithm would be: A, B, C, D But I'm stuck on how to transition from my nested hash-like structure to the results. My psuedo-code is as follows (I can post my ruby code too if someone wants): For each game(g): hash[g.winner][g.loser] += 1 That leaves hash as the first reduction above hash2 = clone of hash For each key(winner), value(losers hash) in hash: For each key(loser), value(losses against winner): hash2[loser][winner] -= losses Which leaves hash2 as the second reduction Feel free to as me question or edit this to be more clear, I'm not sure of how to put it in a very eloquent way. Thanks!

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  • compile error in Ubuntu 10

    - by yozloy
    Hey guys I got a vps which run solusVM. I'm now trying to install ruby 1.9.2 in it. I follow this guide: after I run this command apt-get update apt-get -y install build-essential zlib1g zlib1g-dev libxml2 libxml2-dev libxslt-dev I got this error below root@makserver:/usr/local/src/ruby-1.9.2-p0# apt-get -f install Reading package lists... Done Building dependency tree... Done Correcting dependencies... Done The following extra packages will be installed: libc6 Suggested packages: glibc-doc The following packages will be upgraded: libc6 1 upgraded, 0 newly installed, 0 to remove and 80 not upgraded. Need to get 0B/4252kB of archives. After this operation, 4096B disk space will be freed. Do you want to continue [Y/n]? y debconf: apt-extracttemplates failed: Bad file descriptor (Reading database ... 21594 files and directories currently installed.) Preparing to replace libc6 2.11.1-0ubuntu7.2 (using .../libc6_2.11.1-0ubuntu7.8_amd64.deb) ... open2: fork failed: Cannot allocate memory at /usr/share/perl5/Debconf/ConfModule.pm line 59 dpkg: error processing /var/cache/apt/archives/libc6_2.11.1-0ubuntu7.8_amd64.deb (--unpack): subprocess new pre-installation script returned error exit status 12 Errors were encountered while processing: /var/cache/apt/archives/libc6_2.11.1-0ubuntu7.8_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Anybody can tell me how can I correct this. Thanks

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  • Performing client-side OAuth authorized Twitter API calls versus server side, how much of a difference is there in terms of performance?

    - by Terence Ponce
    I'm working on a Twitter application in Ruby on Rails. One of the biggest arguments that I have with other people on the project is the method of calling the Twitter API. Before, everything was done on the server: OAuth login, updating the user's Twitter data, and retrieving tweets. Retrieving tweets was the heaviest thing to do since we don't store the tweets in our database, so viewing the tweets means that we have to call the API every time. One of the people in the project suggested that we call the tweets through Javascript instead to lessen the load on the server. We used GET search, which, correct me if I'm wrong, will be removed when v1.0 becomes completely deprecated, but that really isn't a concern now. When the Twitter API has migrated completely to v1.1 (again, correct me if I'm wrong), every calls to the API must be authenticated, so we have to authenticate our Javascript requests to the API. As said here: We don't support or recommend performing OAuth directly through Javascript -- it's insecure and puts your application at risk. The only acceptable way to perform it is if you kept all keys and secrets server-side, computed the OAuth signatures and parameters server side, then issued the request client-side from the server-generated OAuth values. If we do exactly what Twitter suggests, the only difference between this and doing everything server-side is that our server won't have to contact the Twitter API anymore every time the user wants to view tweets. Here's how I would picture what's happening every time the user makes a request: If we do it through Javascript, it would be harder on my part because I would have to create the signatures manually for every request, but I will gladly do it if the boost in performance is worth all the trouble. Doing it through Ruby on Rails would be very easy since the Twitter gem does most of the grunt work already, so I'm really encouraging the other people in the project to agree with me. Is the difference in performance trivial or is it significant enough to switch to Javascript?

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  • Huge Opportunity in Small Things

    - by Tori Wieldt
    Addressing the strong demand for Java in the embedded market, Oracle is hosting a new Java Embedded @ JavaOne event in San Francisco October 3-4. The event allows decision makers to attend the Java Embedded @ JavaOne business-focused program, while their IT/development staff can attend the technically-focused JavaOne conference. [Obligatory comment about suits & ties vs. jeans & T-shirts removed.] The two-day event includes keynotes, sessions and demonstrations. In his keynote this morning, Judson Althoff, Senior Vice President of Worldwide Alliances and Channels and Embedded Sales, Oracle explained  Devices are all around us - on 24x7, connected all the time. The explosion of devices is the next IT revolution. Java is the right solution for this space. Java embedded solutions provide a framework to  provision, manage, and secure devices.  Java embedded solutions also provide the ability to aggregate, process and analyze multitude of data.  Java is one platform to program them all. Terrance Barr, Java Evangelist and Java ME expert is enthusiastic about the huge opportunity, "It's the right time and right place for Java Embedded," he said, "Oracle is looking for partners who want to take advantage of this next wave in IT." The Embedded space continues to heat up. Today, Cinterion launched the EHS5, an ultra compact, high-speed M2M communication module providing secure wireless connectivity for a wide variety of industrial applications. Last week, Oracle announced Oracle Java ME Embedded 3.2, a complete client Java runtime Optimized for resource-constrained, connected, embedded systems, Oracle Java Wireless Client 3.2, Oracle Java ME Software Development Kit (SDK) 3.2, and Oracle Java Embedded Suite 7.0 for larger embedded devices. There is a huge opportunity in small things. 

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  • A Huge Opportunity in Small Things

    - by Tori Wieldt
    Addressing the strong demand for Java in the embedded market, Oracle is hosting a new Java Embedded @ JavaOne event in San Francisco October 3-4. The event allows decision makers to attend the Java Embedded @ JavaOne business-focused program, while their IT/development staff can attend the technically-focused JavaOne conference. [Obligatory comment about suits & ties vs. jeans & T-shirts removed.] The two-day event includes keynotes, sessions and demonstrations. In his keynote this morning, Judson Althoff, Senior Vice President of Worldwide Alliances and Channels and Embedded Sales, Oracle explained  Devices are all around us - on 24x7, connected all the time. The explosion of devices is the next IT revolution. Java is the right solution for this space. Java embedded solutions provide a framework to  provision, manage, and secure devices.  Java embedded solutions also provide the ability to aggregate, process and analyze multitude of data.  Java is one platform to program them all. Terrance Barr, Java Evangelist and Java ME expert is enthusiastic about the huge opportunity, "It's the right time and right place for Java Embedded," he said, "Oracle is looking for partners who want to take advantage of this next wave in IT." The Embedded space continues to heat up. Today, Cinterion launched the EHS5, an ultra compact, high-speed M2M communication module providing secure wireless connectivity for a wide variety of industrial applications. Last week, Oracle announced Oracle Java ME Embedded 3.2, a complete client Java runtime Optimized for resource-constrained, connected, embedded systems, Oracle Java Wireless Client 3.2, Oracle Java ME Software Development Kit (SDK) 3.2, and Oracle Java Embedded Suite 7.0 for larger embedded devices. There is a huge opportunity in small things. 

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  • Impossible to do POSTs with appengine-jruby/RoR: Reflection is not allowed

    - by Joel Cuevas
    I'm trying to build a site with RoR on Google App Engine. I'm using the google-appengine gem (http://appengine-jruby.googlecode.com) and following the instructions in (http://gist.github.com/268192). The problem is that I can't submit ANY form! I've already tried this in two diferent clean Win 7 Pro envs and the result is the same. After install Ruby 1.8.6 (One-Click Installer): 1. gem update --system 2. gem install rails 3. gem install google-appengine 4. gem install rails_dm_datastore 5. gem install activerecord-nulldb-adapter 6. curl -O http://appengine-jruby.googlecode.com/hg/demos/rails2/rails2_appengine.rb 7. ruby rails2_appengine.rb (previously downloaded) 8. rails myproj 9. chmod myproj 10. ruby script/generate dd_model MyModel f1:string f2:float f3:float f4:float f5:integer f6:integer f7:integer -f 11. ruby script/generate scaffold MyModel f1:string f2:float f3:float f4:float f5:integer f6:integer f7:integer -f --skip-migration 12. dev_appserver.rb -p 3000 . At this point, I manually test the scaffold in (http://localhost:3000/my_models). The index is OK, then I create a new registry with the generated form, everything's fine, but when I try to create a second one, I get a "java.lang.RuntimeException: DummyDynamicScope should never be used for backref storage" in the console. As far as I read this is a won't-fix behavior in JRuby 1.4.1, but it's converted to a debug only warning in 1.5.0, so I proceed to install the pre release. 13. gem install appengine-jruby-jars --pre With this, that exception is solved and everything works great... until I move the project to the GAE server. 14. ruby appcfg.rb update . And now, in (http://myproj.appspot.com/my_models), again, the index is fine, also the new form, but in the moment that I submit it with valid data, I get a 500 error: "java.lang.IllegalAccessException: Reflection is not allowed on public int". As I said, this behavior is not present in the local SDK. In both cases, I'm completely unable to post anything. This is what I have right now in the GAE environment: Ruby version 1.8.7 (java) RubyGems disabled Rack version 1.1 Rails version 2.3.5 Action Pack version 2.3.5 Active Support version 2.3.5 DataMapper version 0.10.2 Environment production JRuby Runtime version 1.5.0.pre JRuby-Rack version 0.9.7 AppEngine SDK version Google App Engine/1.3.3 AppEngine APIs version 0.0.15 And this are my intalled gems: actionmailer (2.3.5) actionpack (2.3.5) activerecord (2.3.5) activerecord-nulldb-adapter (0.2.0) activeresource (2.3.5) activesupport (2.3.5) addressable (2.1.2) appengine-apis (0.0.15) appengine-jruby-jars (0.0.8.pre, 0.0.7) appengine-rack (0.0.8) appengine-sdk (1.3.3.1) appengine-tools (0.0.12) bundler08 (0.8.5) dm-appengine (0.0.8) dm-ar-finders (0.10.2) dm-core (0.10.2) dm-timestamps (0.10.2) dm-validations (0.10.2) extlib (0.9.14) fxri (0.3.7, 0.3.6) google-appengine (0.0.12) hpricot (0.8.2 x86-mswin32, 0.6 mswin32) jruby-rack (0.9.8, 0.9.7) log4r (1.1.7, 1.0.5) rack (1.1.0, 1.0.1) rails (2.3.5) rails_appengine (0.0.3) rails_dm_datastore (0.2.9) rake (0.8.7, 0.7.3) rubygems-update (1.3.7, 1.3.6) rubyzip (0.9.4) sources (0.0.1) win32-api (1.4.6 x86-mswin32-60, 1.0.4 mswin32) win32-clipboard (0.5.2, 0.4.3) win32-dir (0.3.6, 0.3.2) win32-eventlog (0.5.2, 0.4.6) win32-file (0.6.3, 0.5.4) win32-file-stat (1.3.4, 1.2.7) win32-process (0.6.2, 0.5.3) win32-sapi (0.1.5, 0.1.4) win32-sound (0.4.2, 0.4.1) windows-api (0.4.0, 0.2.0) windows-pr (1.0.9, 0.7.2) I'm unable to attach the full logs of the exceptions because of the character limits, but I can provide them under request. Here's an abstract of them: DummyDynamicScope (dev and prod envs): 14-may-2010 7:18:40 com.google.appengine.tools.development.ApiProxyLocalImpl log SEVERE: [1273821520195000] javax.servlet.ServletContext log: Application Error java.lang.RuntimeException: DummyDynamicScope should never be used for backref storage at org.jruby.runtime.scope.DummyDynamicScope.getBackRef(DummyDynamicScope.java:49) at org.jruby.RubyRegexp.updateBackRef(RubyRegexp.java:1404) at org.jruby.RubyRegexp.updateBackRef(RubyRegexp.java:1396) at org.jruby.RubyRegexp.search(RubyRegexp.java:1386) at org.jruby.RubyRegexp.op_match(RubyRegexp.java:1301) at org.jruby.RubyString.op_match(RubyString.java:1446) at org.jruby.RubyString$i_method_1_0$RUBYINVOKER$op_match.call(org/jruby/RubyString$i_method_1_0$RUBYINVOKER$op_match.gen) at org.jruby.internal.runtime.methods.JavaMethod$JavaMethodOneOrN.call(JavaMethod.java:721) at org.jruby.RubyClass.finvoke(RubyClass.java:472) at org.jruby.RubyObject.send(RubyObject.java:1442) at org.jruby.RubyObject$i_method_multi$RUBYINVOKER$send.call(org/jruby/RubyObject$i_method_multi$RUBYINVOKER$send.gen) at org.jruby.internal.runtime.methods.JavaMethod$JavaMethodZeroOrOneOrTwoOrNBlock.call(JavaMethod.java:276) at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:330) at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:189) at ruby.jit.ruby.C_3a_.Desarrollo.AppEngine.gorgory.WEB_minus_INF.lib.gems_dot_jar.bundler_gems.jruby.$1_dot_8.gems.dm_minus_validations_minus_0_dot_10_dot_2.lib.dm_minus_validations.validators.numeric_validator.validate_with_comparison at ruby.jit.ruby.C_3a_.Desarrollo.AppEngine.gorgory.WEB_minus_INF.lib.gems_dot_jar.bundler_gems.jruby.$1_dot_8.gems.dm_minus_validations_minus_0_dot_10_dot_2.lib.dm_minus_validations.validators.numeric_validator.validate_with_comparison at org.jruby.internal.runtime.methods.JittedMethod.call(JittedMethod.java:102) at org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:144) at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:280) at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:69) at org.jruby.ast.FCallManyArgsNode.interpret(FCallManyArgsNode.java:60) at org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104) at org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:229) at org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:193) at org.jruby.RubyClass.finvoke(RubyClass.java:491) at org.jruby.RubyObject.send(RubyObject.java:1448) at org.jruby.RubyObject$i_method_multi$RUBYINVOKER$send.call(org/jruby/RubyObject$i_method_multi$RUBYINVOKER$send.gen) at org.jruby.internal.runtime.methods.JavaMethod$JavaMethodZeroOrOneOrTwoOrThreeOrNBlock.call(JavaMethod.java:293) at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:350) at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:229) at ruby.jit.ruby.C_3a_.Desarrollo.AppEngine.gorgory.WEB_minus_INF.lib.gems_dot_jar.bundler_gems.jruby.$1_dot_8.gems.dm_minus_validations_minus_0_dot_10_dot_2.lib.dm_minus_validations.validators.numeric_validator.validate_with28985350_50 at ruby.jit.ruby.C_3a_.Desarrollo.AppEngine.gorgory.WEB_minus_INF.lib.gems_dot_jar.bundler_gems.jruby.$1_dot_8.gems.dm_minus_validations_minus_0_dot_10_dot_2.lib.dm_minus_validations.validators.numeric_validator.validate_with28985350_50 at org.jruby.internal.runtime.methods.JittedMethod.call(JittedMethod.java:221) at org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:201) at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:227) at org.jruby.ast.FCallThreeArgNode.interpret(FCallThreeArgNode.java:40) Reflection (only prod env): Java::JavaLang::SecurityException (java.lang.IllegalAccessException: Reflection is not allowed on public int java.lang.String$CaseInsensitiveComparator.compare(java.lang.String,java.lang.String)): com.google.appengine.runtime.Request.process-92563a0605f433ea(Request.java) java.lang.reflect.AccessibleObject.setAccessible(AccessibleObject.java:40) org.jruby.javasupport.JavaMethod.<init>(JavaMethod.java:176) org.jruby.javasupport.JavaMethod.create(JavaMethod.java:183) org.jruby.java.invokers.MethodInvoker.createCallable(MethodInvoker.java:23) org.jruby.java.invokers.RubyToJavaInvoker.<init>(RubyToJavaInvoker.java:63) org.jruby.java.invokers.MethodInvoker.<init>(MethodInvoker.java:13) org.jruby.java.invokers.InstanceMethodInvoker.<init>(InstanceMethodInvoker.java:15) org.jruby.javasupport.JavaClass$InstanceMethodInvokerInstaller.install(JavaClass.java:339) org.jruby.javasupport.JavaClass.installClassMethods(JavaClass.java:723) org.jruby.javasupport.JavaClass.setupProxy(JavaClass.java:586) org.jruby.javasupport.Java.createProxyClass(Java.java:506) org.jruby.javasupport.Java.getProxyClass(Java.java:445) org.jruby.javasupport.Java.getInstance(Java.java:354) org.jruby.javasupport.JavaUtil.convertJavaToUsableRubyObject(JavaUtil.java:143) org.jruby.javasupport.JavaClass$ConstantField.install(JavaClass.java:360) org.jruby.javasupport.JavaClass.installClassFields(JavaClass.java:711) org.jruby.javasupport.JavaClass.setupProxy(JavaClass.java:585) org.jruby.javasupport.Java.createProxyClass(Java.java:506) org.jruby.javasupport.Java.getProxyClass(Java.java:445) org.jruby.javasupport.Java.getProxyOrPackageUnderPackage(Java.java:885) org.jruby.javasupport.Java.get_proxy_or_package_under_package(Java.java:918) org.jruby.javasupport.JavaUtilities.get_proxy_or_package_under_package(JavaUtilities.java:54) org.jruby.javasupport.JavaUtilities$s_method_2_0$RUBYINVOKER$get_proxy_or_package_under_package.call(org/jruby/javasupport/JavaUtilities$s_method_2_0$RUBYINVOKER$get_proxy_or_package_under_package.gen:65535) org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:329) org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:188) org.jruby.ast.CallTwoArgNode.interpret(CallTwoArgNode.java:59) org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104) org.jruby.ast.BlockNode.interpret(BlockNode.java:71) org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:113) org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:138) org.jruby.javasupport.util.RuntimeHelpers$MethodMissingMethod.call(RuntimeHelpers.java:389) org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:182) What should I do now? Any hint would be wellcome. Thanks!

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  • yahoo media player not working.

    - by luca590
    I have a yahoo media player embedded in my webpage. I am currently using Ruby on Rails to create/edit my web page. When i click the play button next to a track the YMP waits a while and then goes to the next track without playing the first one. I then get a warning on my second (last) track that its file could not be found. Does anyone has a better recommendation for an audio player or a way to fix this one?

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  • yahoo media player not working

    - by luca590
    I have a yahoo media player embedded in my webpage. I am currently using Ruby on Rails to create/edit my web page. When i click the play button next to a track the YMP waits a while and then goes to the next track without playing the first one. I then get a warning on my second (last) track that its file could not be found. Does anyone has a better recommendation for an audio player or a way to fix this one?

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  • What's the best way of accessing a DRb object (e.g. Ruby Queue) from Scala (and Java)?

    - by Tom Morris
    I have built a variety of little scripts using Ruby's very simple Queue class, and share the Queue between Ruby and JRuby processes using DRb. It would be nice to be able to access these from Scala (and maybe Java) using JRuby. I've put together something Scala and the JSR-223 interface to access jruby-complete.jar. import javax.script._ class DRbQueue(host: String, port: Int) { private var engine = DRbQueue.factory.getEngineByName("jruby") private var invoker = engine.asInstanceOf[Invocable] engine.eval("require \"drb\" ") private var queue = engine.eval("DRbObject.new(nil, \"druby://" + host + ":" + port.toString + "\")") def isEmpty(): Boolean = invoker.invokeMethod(this.queue, "empty?").asInstanceOf[Boolean] def size(): Long = invoker.invokeMethod(this.queue, "length").asInstanceOf[Long] def threadsWaiting: Long = invoker.invokeMethod(this.queue, "num_waiting").asInstanceOf[Long] def offer(obj: Any) = invoker.invokeMethod(this.queue, "push", obj.asInstanceOf[java.lang.Object]) def poll(): Any = invoker.invokeMethod(this.queue, "pop") def clear(): Unit = { invoker.invokeMethod(this.queue, "clear") } } object DRbQueue { var factory = new ScriptEngineManager() } (It conforms roughly to java.util.Queue interface, but I haven't declared the interface because it doesn't implement the element and peek methods because the Ruby class doesn't offer them.) The problem with this is the type conversion. JRuby is fine with Scala's Strings - because they are Java strings. But if I give it a Scala Int or Long, or one of the other Scala types (List, Set, RichString, Array, Symbol) or some other custom type. This seems unnecessarily hacky: surely there has got to be a better way of doing RMI/DRb interop without having to use JSR-223 API. I could either make it so that the offer method serializes the object to, say, a JSON string and takes a structural type of only objects that have a toJson method. I could then write a Ruby wrapper class (or just monkeypatch Queue) to would parse the JSON. Is there any point in carrying on with trying to access DRb from Java/Scala? Might it just be easier to install a real message queue? (If so, any suggestions for a lightweight JVM-based MQ?)

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  • Visual Studio 2010 and javascript debugging in external javascript files (embedded and minified).

    - by OKB
    Hi, The asp.net web application I'm working on is written in asp.net 3.5, the web app solution is upgraded from VS 2008 (don't know if that matter). The solution had javascript in the aspx files before I moved the javascript to external files. Now what I have done is to set all the javascript files to be embedded resource (except the jquery.js file) and I want to minify them when building for release by using the MS Ajax Minifier. I want to use the minified javascript files when I'm in the RELEASE mode and when I'm in DEBUG mode I want to use the "normal" versions. My problem now is that I'm unable to debug the javascript code in debug mode. When I set a break point a javascript function, VS is not breaking at all when the function is executed. I have added this entry in my web.config: <system.web> <compilation defaultLanguage="c#" debug="true" /> </system.web> Here how I register the jquery in an aspx-file: <asp:ScriptManagerProxy ID="ScriptManagerProxy1" runat="server"> <Scripts> <asp:ScriptReference Path="~/Javascript/jquery.js"/> </Scripts> </asp:ScriptManagerProxy> External javascript registration in the code-behind: #if DEBUG [assembly: WebResource("braArkivWeb.Javascript.jquery.js", "text/javascript")] [assembly: WebResource(braArkivWeb.ArkivdelSearch.JavaScriptResource, "text/javascript")] #else [assembly: WebResource("braArkivWeb.Javascript.jquery.min.js", "text/javascript")] [assembly: WebResource(braArkivWeb.ArkivdelSearch.JavaScriptMinResource, "text/javascript")] #endif public partial class ArkivdelSearch : Page { public const string JavaScriptResource = "braArkivWeb.ArkivdelSearch.js"; public const string JavaScriptMinResource = "braArkivWeb.ArkivdelSearch.min.js"; protected void Page_Init(object sender, EventArgs e) { InitPageClientScript(); } private void InitPageClientScript() { #if DEBUG this.Page.ClientScript.RegisterClientScriptResource(typeof(ArkivdelSearch), "braArkivWeb.Javascript.jquery.js"); this.Page.ClientScript.RegisterClientScriptResource(typeof(ArkivdelSearch), JavaScriptResource); #else this.Page.ClientScript.RegisterClientScriptResource(typeof(ArkivdelSearch), "braArkivWeb.Javascript.jquery.min.js"); this.Page.ClientScript.RegisterClientScriptResource(typeof(ArkivdelSearch), JavaScriptMinResource); #endif StringBuilder sb = new StringBuilder(); Page.ClientScript.RegisterStartupScript(typeof(ArkivdelSearch), "initArkivdelSearch", sb.ToString(), true); } } In the project file I have added this code to minify the javascripts: <!-- Minify all JavaScript files that were embedded as resources --> <UsingTask TaskName="AjaxMin" AssemblyFile="$(MSBuildProjectDirectory)\..\..\SharedLib\AjaxMinTask.dll" /> <PropertyGroup> <ResGenDependsOn> MinifyJavaScript; $(ResGenDependsOn) </ResGenDependsOn> </PropertyGroup> <Target Name="MinifyJavaScript" Condition=" '$(ConfigurationName)'=='Release' "> <Copy SourceFiles="@(EmbeddedResource)" DestinationFolder="$(IntermediateOutputPath)" Condition="'%(Extension)'=='.js'"> <Output TaskParameter="DestinationFiles" ItemName="EmbeddedJavaScriptResource" /> </Copy> <AjaxMin JsSourceFiles="@(EmbeddedJavaScriptResource)" JsSourceExtensionPattern="\.js$" JsTargetExtension=".js" /> <ItemGroup> <EmbeddedResource Remove="@(EmbeddedResource)" Condition="'%(Extension)'=='.js'" /> <EmbeddedResource Include="@(EmbeddedJavaScriptResource)" /> <FileWrites Include="@(EmbeddedJavaScriptResource)" /> </ItemGroup> </Target> Do you see what I'm doing wrong? Or what I'm missing in order to be able to debug my javascript code? Best Regards, OKB

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  • Why is curl in Ruby slower than command-line curl?

    - by Stiivi
    I am trying to download more than 1m pages (URLs ending by a sequence ID). I have implemented kind of multi-purpose download manager with configurable number of download threads and one processing thread. The downloader downloads files in batches: curl = Curl::Easy.new batch_urls.each { |url_info| curl.url = url_info[:url] curl.perform file = File.new(url_info[:file], "wb") file << curl.body_str file.close # ... some other stuff } I have tried to download 8000 pages sample. When using the code above, I get 1000 in 2 minutes. When I write all URLs into a file and do in shell: cat list | xargs curl I gen all 8000 pages in two minutes. Thing is, I need it to have it in ruby code, because there is other monitoring and processing code. I have tried: Curl::Multi - it is somehow faster, but misses 50-90% of files (does not download them and gives no reason/code) multiple threads with Curl::Easy - around the same speed as single threaded Why is reused Curl::Easy slower than subsequent command line curl calls and how can I make it faster? Or what I am doing wrong? I would prefer to fix my download manager code than to make downloading for this case in a different way. Before this, I was calling command-line wget which I provided with a file with list of URLs. Howerver, not all errors were handled, also it was not possible to specify output file for each URL separately when using URL list. Now it seems to me that the best way would be to use multiple threads with system call to 'curl' command. But why when I can use directly Curl in Ruby? Code for the download manager is here, if it might help: Download Manager (I have played with timeouts, from not-setting it to various values, it did not seem help) Any hints appreciated.

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  • Ruby: Why is Array.sort slow for large objects?

    - by David Waller
    A colleague needed to sort an array of ActiveRecord objects in a Rails app. He tried the obvious Array.sort! but it seemed surprisingly slow, taking 32s for an array of 3700 objects. So just in case it was these big fat objects slowing things down, he reimplemented the sort by sorting an array of small objects, then reordering the original array of ActiveRecord objects to match - as shown in the code below. Tada! The sort now takes 700ms. That really surprised me. Does Ruby's sort method end up copying objects about the place rather than just references? He's using Ruby 1.8.6/7. def self.sort_events(events) event_sorters = Array.new(events.length) {|i| EventSorter.new(i, events[i])} event_sorters.sort! event_sorters.collect {|es| events[es.index]} end private # Class used by sort_events class EventSorter attr_reader :sqn attr_reader :time attr_reader :index def initialize(index, event) @index = index @sqn = event.sqn @time = event.time end def <=>(b) @time != b.time ? @time <=> b.time : @sqn <=> b.sqn end end

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  • Help me write my LISP :) LISP environments, Ruby Hashes...

    - by MikeC8
    I'm implementing a rudimentary version of LISP in Ruby just in order to familiarize myself with some concepts. I'm basing my implementation off of Peter Norvig's Lispy (http://norvig.com/lispy.html). There's something I'm missing here though, and I'd appreciate some help... He subclasses Python's dict as follows: class Env(dict): "An environment: a dict of {'var':val} pairs, with an outer Env." def __init__(self, parms=(), args=(), outer=None): self.update(zip(parms,args)) self.outer = outer def find(self, var): "Find the innermost Env where var appears." return self if var in self else self.outer.find(var) He then goes on to explain why he does this rather than just using a dict. However, for some reason, his explanation keeps passing in through my eyes and out through the back of my head. Why not use a dict, and then inside the eval function, when a new "sub-environment" needs to be created, just take the existing dict and update the key/value pairs that need to be updated, and pass that new dict into the next eval? Won't the Python interpreter keep track of the previous "outer" envs? And won't the nature of the recursion ensure that the values are pulled out from "inner" to "outer"? I'm using Ruby, and I tried to implement things this way. Something's not working though, and it might be because of this, or perhaps not. Here's my eval function, env being a regular Hash: def eval(x, env = $global_env) ........ elsif x[0] == "lambda" then ->(*args) { eval(x[2], env.merge(Hash[*x[1].zip(args).flatten(1)])) } ........ end The line that matters of course is the "lambda" one. If there is a difference, what's importantly different between what I'm doing here and what Norvig did with his Env class? If there's no difference, then perhaps someone can enlighten me as to why Norvig uses the Env class. Thanks :)

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  • Career choice, job offer advice

    - by ivan
    Hi, beginner developer here (around 1-1.5 years of experience). I've recently got an iOs development offer and also an opportunity to start career at embedded development (at another company). I'd be grateful for general thoughts on mobile and embedded development perspectives in a few years, just general advices, or may be links to good articles and discussions on the topic. Both choices have personal pros and cons in terms of interest, salary and what's not and I'm stuck with this atm. Also, I live in a almost purely outsorcing country (Ukraine), this probably matters too. Thank you for any help.

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  • RTOS experience

    - by Subbu
    Hi, I have been working as an embedded software engineer on mostly 8 bit micro-controller firmware and desktop/mobile applications development for the past five years. My work on a WinCE project (in which I got introduced to .NET CF) was short lived. I did use core APIs for interrupt processing, peripheral communication, etc...but again, not exactly a pure RTOS environment. In order to get together more solid experience for growing more in the embedded field, I want to work more with RTOSes. Will buying an evaluation board with an RTOS and putting together a project at home be regarded as a good experience or will an online course be more useful? I am just not clear as to what will be regarded as good experience. Any suggestions or directions will greatly help me. I have a passion for the field but just a need a point in the right direction. Thanks for any help in advance. Regards, Subbu

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  • RTOS experience

    - by Subbu
    I have been working as an embedded software engineer on mostly 8 bit micro-controller firmware and desktop/mobile applications development for the past five years. My work on a WinCE project (in which I got introduced to .NET CF) was short lived. I did use core APIs for interrupt processing, peripheral communication, etc...but again, not exactly a pure RTOS environment. In order to get together more solid experience for growing more in the embedded field, I want to work more with RTOSes. Will buying an evaluation board with an RTOS and putting together a project at home be regarded as a good experience or will an online course be more useful? I am just not clear as to what will be regarded as good experience. Any suggestions or directions will greatly help me. I have a passion for the field but just a need a point in the right direction.

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  • What exactly is a chroot? Is it similar to a simultaneous dual boot?

    - by mathematician1975
    It has been suggested to me that the use of a chroot might solve my problem of building an application that must run on an embedded device. I have inferred from this description that it is somehow similar to creating the embedded environment locally on my machine which I can then use to develop on from my desktop development machine. Is this the right way to look at the functionality or have I totally misunderstood? In order to get some idea of how it works I read this https://wiki.ubuntu.com/DebootstrapChroot which I will attempt to make a chroot for an old Ubuntu version on my machine. However, as I am a total linux novice, I am a bit concerned that as I do not entirely know what I am doing is there anyway that I could end up with an unusable system?? Is this something that a novice should even attempt???

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