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  • Best Books for Learning to Test Software

    - by Chris
    I have read a lot of programming books, many mention testing of various kinds. I have never really gotten into the topic of testing, but I realize how extremely important it is. Anyone know of some good books that provide a thorough exploration of this topic?

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  • Abstract away a compound identity value for use in business logic?

    - by John K
    While separating business logic and data access logic into two different assemblies, I want to abstract away the concept of identity so that the business logic deals with one consistent identity without having to understand its actual representation in the data source. I've been calling this a compound identity abstraction. Data sources in this project are swappable and various and the business logic shouldn't care which data source is currently in use. The identity is the toughest part because its implementation can change per kind of data source, whereas other fields like name, address, etc are consistently scalar values. What I'm searching for is a good way to abstract the concept of identity, whether it be an existing library, a software pattern or just a solid good idea of some kind is provided. The proposed compound identity value would have to be comparable and usable in the business logic and passed back to the data source to specify records, entities and/or documents to affect, so the data source must be able to parse back out the details of its own compound ids. Data Source Examples: This serves to provide an idea of what I mean by various data sources having different identity implementations. A relational data source might express a piece of content with an integer identifier plus a language specific code. For example. content_id language Other Columns expressing details of content 1 en_us 1 fr_ca The identity of the first record in the above example is: 1 + en_us However when a NoSQL data source is substituted, it might somehow represent each piece of content with a GUID string 936DA01F-9ABD-4d9d-80C7-02AF85C822A8 plus language code of a different standardization, And a third kind of data source might use just a simple scalar value. So on and so forth, you get the idea.

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  • What software will tell me if I've already downloaded a video? [closed]

    - by dave
    (I use Linux KNOPPIX (distro 7.0.2, ver 3.3.7) on hard drive.) I download videos of TV programs from the 60s and 70s (mainly from youtube). I copy the youtube URL then paste it into www.keepvid.com to download it (usually .mp4 format). Having now got dozens of such video files (and growing) on my hard drive, I'd like to organise them. WHAT I'D LIKE TO DO IS: Say I find a new vid (of a TV prog) on youtube (or another site), and I'm about to download it. It's possible that I've WATCHED IT BEFORE but have forgotten. So is there software out there that I can run which will do the following: Check for me if I've ALREADY WATCHED the vid that I'm about to download. At the moment, once I've watched a vid on my hard drive, I move the file to another directory called "Watched". But this of course doesn't alert me in the immediate way that I want. . It would crudely suffice, if the software told me AFTER I've downloaded the vid, if I've ALREADY WATCHED it (ie if it's already in my "Watched" directory, or perhaps in a "watched" list). I sometimes alter the filename of the original video file on hard drive, so this might spoil a comparison. If the software alerts me to the fact that I've already watched the vid (preferably BEFORE I download it), then this will allow me to confidently download only new vids that I haven't watched before, and save me duplicating my effort. I'd be most grateful if anyone can suggest such a piece of software, or an alternative solution. I'll be honest, I avoid software that infringes your privacy and control - you know, software that automatically does things behind your back, like upgrades itself over the internet, puts things on your hard drive that you didn't ask for, or sends information from your hard drive to websites.

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  • About Sdram software :Self-refresh mode

    - by student_pdas
    For power management we have to put system in deep sleep(system sleep) mode and for this we have to put SDRAM in self refresh mode. Can anyone tell the steps to set SDARM in self refresh mode. I tried SDRAM configuration register's ,I found that the SDRAM do goes to self-refresh mode[we probed the SD clk out] however system crashes in some scenarios while coming out of sleep.

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  • Error starting modern compiler

    - by saloni
    In my servlet , I m using Tomcat 5.0 and JRE is 1.5.0 but it is giving error when I click on the URL . As when I created a war file of my project and deployed in tomcat than it is working fine . It means that only problem with my eclipse configuration ERROR IS : - Apr 5, 2010 3:20:22 PM org.apache.jasper.compiler.Compiler generateClass SEVERE: Javac exception Error starting modern compiler at org.apache.tools.ant.taskdefs.compilers.Javac13.execute(Javac13.java:69) at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:942) at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:764) at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:382) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:472) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:451) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:439) at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.apache.tools.ant.taskdefs.compilers.Javac13.execute(Javac13.java:61) ... 35 more Caused by: java.lang.VerifyError: class com.sun.tools.javac.jvm.Target overrides final method . at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1634) at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:860) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1307) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at com.sun.tools.javac.Main.compile(Main.java:42) ... 40 more --- Nested Exception --- java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.apache.tools.ant.taskdefs.compilers.Javac13.execute(Javac13.java:61) at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:942) at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:764) at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:382) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:472) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:451) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:439) at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.VerifyError: class com.sun.tools.javac.jvm.Target overrides final method . at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1634) at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:860) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1307) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at com.sun.tools.javac.Main.compile(Main.java:42) ... 40 more Apr 5, 2010 3:20:22 PM org.apache.jasper.compiler.Compiler generateClass SEVERE: Env: Compile: javaFileName=/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/work/Catalina/localhost/SampleSaloni//org/apache/jsp/page\form_jsp.java classpath=/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/classes/;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/ant-launcher.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/ant.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-collections-3.1.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-dbcp-1.2.1.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-el.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-pool-1.2.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jasper-compiler.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jasper-runtime.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jsp-api.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-common.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-factory.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-java.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-resources.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/tools.jar;D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\SampleSaloni;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/classes/;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/ant-launcher.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/ant.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-collections-3.1.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-dbcp-1.2.1.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-el.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/commons-pool-1.2.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jasper-compiler.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jasper-runtime.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/jsp-api.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-common.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-factory.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-java.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/naming-resources.jar;/D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/SampleSaloni/WEB-INF/lib/tools.jar;D:/software setups/jakarta-tomcat-5.0.28/common/classes/;D:/software setups/jakarta-tomcat-5.0.28/common/lib/ant-launcher.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/ant.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/commons-collections-3.1.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/commons-dbcp-1.2.1.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/commons-el.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/commons-pool-1.2.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/jasper-compiler.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/jasper-runtime.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/jsp-api.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/naming-common.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/naming-factory.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/naming-java.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/naming-resources.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/servlet-api.jar;D:/software setups/jakarta-tomcat-5.0.28/common/lib/tools.jar;/D:/software%20setups/jakarta-tomcat-5.0.28/bin/bootstrap.jar;/C:/Program%20Files/Java/jre1.5.0_09/lib/ext/dnsns.jar;/C:/Program%20Files/Java/jre1.5.0_09/lib/ext/sunjce_provider.jar;/C:/Program%20Files/Java/jre1.5.0_09/lib/ext/sunpkcs11.jar cp=D:\software setups\jakarta-tomcat-5.0.28\bin\bootstrap.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\classes cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\ant-launcher.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\ant.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-collections-3.1.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-dbcp-1.2.1.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-el.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-pool-1.2.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jasper-compiler.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jasper-runtime.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jsp-api.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-common.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-factory.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-java.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-resources.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\tools.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\SampleSaloni cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\classes cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\ant-launcher.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\ant.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-collections-3.1.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-dbcp-1.2.1.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-el.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\commons-pool-1.2.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jasper-compiler.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jasper-runtime.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\jsp-api.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-common.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-factory.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-java.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\naming-resources.jar cp=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SampleSaloni\WEB-INF\lib\tools.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\classes cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\ant-launcher.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\ant.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\commons-collections-3.1.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\commons-dbcp-1.2.1.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\commons-el.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\commons-pool-1.2.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\jasper-compiler.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\jasper-runtime.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\jsp-api.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\naming-common.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\naming-factory.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\naming-java.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\naming-resources.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\servlet-api.jar cp=D:\software setups\jakarta-tomcat-5.0.28\common\lib\tools.jar cp=D:\software%20setups\jakarta-tomcat-5.0.28\bin\bootstrap.jar cp=C:\Program%20Files\Java\jre1.5.0_09\lib\ext\dnsns.jar cp=C:\Program%20Files\Java\jre1.5.0_09\lib\ext\sunjce_provider.jar cp=C:\Program%20Files\Java\jre1.5.0_09\lib\ext\sunpkcs11.jar work dir=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\SampleSaloni extension dir=C:\Program Files\Java\jre1.5.0_09\lib\ext srcDir=D:\OffViv\JAVA_IDE\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\SampleSaloni include=org/apache/jsp/page/form_jsp.java Apr 5, 2010 3:20:22 PM org.apache.jasper.compiler.Compiler generateClass SEVERE: Error compiling file: /D:/OffViv/JAVA_IDE/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/work/Catalina/localhost/SampleSaloni//org/apache/jsp/page\form_jsp.java [javac] Compiling 1 source file

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  • Design for Vacation Tracking System

    - by Aaronaught
    I have been tasked with developing a system for tracking our company's paid time-off (vacation, sick days, etc.) At the moment we are using an Excel spreadsheet on a shared network drive, and it works pretty well, but we are concerned that we won't be able to "trust" employees forever and sometimes we run into locking issues when two people try to open the spreadsheet at once. So we are trying to build something a little more robust. I would like some input on this design in terms of maintainability, scalability, extensibility, etc. It's a pretty simple workflow we need to represent right now: I started with a basic MS Access schema like this: Employees (EmpID int, EmpName varchar(50), AllowedDays int) Vacations (VacationID int, EmpID int, BeginDate datetime, EndDate datetime) But we don't want to spend a lot of time building a schema and database like this and have to change it later, so I think I am going to go with something that will be easier to expand through configuration. Right now the vacation table has this schema: Vacations (VacationID int, PropName varchar(50), PropValue varchar(50)) And the table will be populated with data like this: VacationID | PropName | PropValue -----------+--------------+------------------ 1 | EmpID | 4 1 | EmpName | James Jones 1 | Reason | Vacation 1 | BeginDate | 2/24/2010 1 | EndDate | 2/30/2010 1 | Destination | Spectate Swamp 2 | ... | ... I think this is a pretty good, extensible design, we can easily add new properties to the vacation like the destination or maybe approval status, etc. I wasn't too sure how to go about managing the database of valid properties, I thought of putting them in a separate PropNames table but it gets complicated to manage all the different data types and people say that you shouldn't put CLR type names into a SQL database, so I decided to use XML instead, here is the schema: <VacationProperties> <PropertyNames>EmpID,EmpName,Reason,BeginDate,EndDate,Destination</PropertyNames> <PropertyTypes>System.Int32,System.String,System.String,System.DateTime,System.DateTime,System.String</PropertyTypes> <PropertiesRequired>true,true,false,true,true,false</PropertiesRequired> </VacationProperties> I might need more fields than that, I'm not completely sure. I'm parsing the XML like this (would like some feedback on the parsing code): string xml = File.ReadAllText("properties.xml"); Match m = Regex.Match(xml, "<(PropertyNames)>(.*?)</PropertyNames>"; string[] pn = m.Value.Split(','); // do the same for PropertyTypes, PropertiesRequired Then I use the following code to persist configuration changes to the database: string sql = "DROP TABLE VacationProperties"; sql = sql + " CREATE TABLE VacationProperties "; sql = sql + "(PropertyName varchar(100), PropertyType varchar(100) "; sql = sql + "IsRequired varchar(100))"; for (int i = 0; i < pn.Length; i++) { sql = sql + " INSERT VacationProperties VALUES (" + pn[i] + "," + pt[i] + "," + pv[i] + ")"; } // GlobalConnection is a singleton new SqlCommand(sql, GlobalConnection.Instance).ExecuteReader(); So far so good, but after a few days of this I then realized that a lot of this was just a more specific kind of a generic workflow which could be further abstracted, and instead of writing all of this boilerplate plumbing code I could just come up with a workflow and plug it into a workflow engine like Windows Workflow Foundation and have the users configure it: In order to support routing these configurations throw the workflow system, it seemed natural to implement generic XML Web Services for this instead of just using an XML file as above. I've used this code to implement the Web Services: public class VacationConfigurationService : WebService { [WebMethod] public void UpdateConfiguration(string xml) { // Above code goes here } } Which was pretty easy, although I'm still working on a way to validate that XML against some kind of schema as there's no error-checking yet. I also created a few different services for other operations like VacationSubmissionService, VacationReportService, VacationDataService, VacationAuthenticationService, etc. The whole Service Oriented Architecture looks like this: And because the workflow itself might change, I have been working on a way to integrate the WF workflow system with MS Visio, which everybody at the office already knows how to use so they could make changes pretty easily. We have a diagram that looks like the following (it's kind of hard to read but the main items are Activities, Authenticators, Validators, Transformers, Processors, and Data Connections, they're all analogous to the services in the SOA diagram above). The requirements for this system are: (Note - I don't control these, they were given to me by management) Main workflow must interface with Excel spreadsheet, probably through VBA macros (to ease the transition to the new system) Alerts should integrate with MS Outlook, Lotus Notes, and SMS (text messages). We also want to interface it with the company Voice Mail system but that is not a "hard" requirement. Performance requirements: Must handle 250,000 Transactions Per Second Should be able to handle up to 20,000 employees (right now we have 3) 99.99% uptime ("four nines") expected Must be secure against outside hacking, but users cannot be required to enter a username/password. Platforms: Must support Windows XP/Vista/7, Linux, iPhone, Blackberry, DOS 2.0, VAX, IRIX, PDP-11, Apple IIc. Time to complete: 6 to 8 weeks. My questions are: Is this a good design for the system so far? Am I using all of the recommended best practices for these technologies? How do I integrate the Visio diagram above with the Windows Workflow Foundation to call the ConfigurationService and persist workflow changes? Am I missing any important components? Will this be extensible enough to support any scenario via end-user configuration? Will the system scale to the above performance requirements? Will we need any expensive hardware to run it? Are there any "gotchas" I should know about with respect to cross-platform compatibility? For example would it be difficult to convert this to an iPhone app? How long would you expect this to take? (We've dedicated 1 week for testing so I'm thinking maybe 5 weeks?)

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  • Is the design notion of layers contrived?

    - by Bruce
    Hi all I'm reading through Eric Evans' awesome work, Domain-Driven Design. However, I can't help feeling that the 'layers' model is contrived. To expand on that statement, it seems as if it tries to shoe-horn various concepts into a specific, neat model, that of layers talking to each other. It seems to me that the layers model is too simplified to actually capture the way that (good) software works. To expand further: Evans says: "Partition a complex program into layers. Develop a design within each layer that is cohesive and that depends only on the layers below. Follow standard architectural patterns to provide loose coupling to the layers above." Maybe I'm misunderstanding what 'depends' means, but as far as I can see, it can either mean a) Class X (in the UI for example) has a reference to a concrete class Y (in the main application) or b) Class X has a reference to a class Y-ish object providing class Y-ish services (ie a reference held as an interface). If it means (a), then this is clearly a bad thing, since it defeats re-using the UI as a front-end to some other application that provides Y-ish functionality. But if it means (b), then how is the UI any more dependent on the application, than the application is dependent on the UI? Both are decoupled from each other as much as they can be while still talking to each other. Evans' layer model of dependencies going one way seems too neat. First, isn't it more accurate to say that each area of the design provides a module that is pretty much an island to itself, and that ideally all communication is through interfaces, in a contract-driven/responsibility-driven paradigm? (ie, the 'dependency only on lower layers' is contrived). Likewise with the domain layer talking to the database - the domain layer is as decoupled (through DAO etc) from the database as the database is from the domain layer. Neither is dependent on the other, both can be swapped out. Second, the idea of a conceptual straight line (as in from one layer to the next) is artificial - isn't there more a network of intercommunicating but separate modules, including external services, utility services and so on, branching off at different angles? Thanks all - hoping that your responses can clarify my understanding on this..

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  • MVC and conditional formatting - strategies for implementation

    - by Extrakun
    Right now I am writing a simulation program which output is formatted according to certain factors. The question is in a MVC architecture, where is the conditional formatting to be taken place? What are some strategies for implement this feature? FYI, The platform I am using is rather bare-bone in its GUI/front-end execution. To change color and formatting, it requires a change to the formatting state (much like OpenGL).

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  • Craftsmanship is ALL that Matters

    - by Wayne Molina
    Today, I'm going to talk about a touchy subject: the notion of working in a company that doesn't use the prescribed "best practices" in its software development endeavours.  Over the years I have, using a variety of pseudonyms, asked this question on popular programming forums.  Although I always add in some minor variation of the story to avoid suspicion that it's the same person posting, the crux of the tale remains the same: A Programmer’s Tale A junior software developer has just started a new job at an average company, creating average line-of-business applications for internal use (the most typical scenario programmers find themselves in).  This hypothetical newbie has spent a lot of time reading up on the "theory" of software development, devouring books, blogs and screencasts from well-known and respected software developers in the community in order to broaden his knowledge and "do what the pros do".  He begins his new job, eager to apply what he's learned on a real-world project only to discover that his new teammates doesn't use any of those concepts and techniques.  They hack their way through development, or in a best-case scenario use some homebrew, thrown-together semblance of a framework for their applications that follows not one of the best practices suggested by the “elite” in the software community - things like TDD (TDD as a "best practice" is the only subjective part of this post, but it's included here due to a very large following of respected developers who consider it one), the SOLID principles, well-known and venerable tools, even version control in a worst case and truly nightmarish scenario.  Our protagonist is frustrated that he isn't doing things the "proper" way - a way he's spent personal time digesting and learning about and, more importantly, a way that some of the top developers in the industry advocate - and turns to a forum to ask the advice of his peers. Invariably the answer I, in the guise of the concerned newbie, will receive is that A) I don't know anything and should just shut my mouth and sling code the bad way like everybody else on the team, and B) These "best practices" are fade or a joke, and the only thing that matters is shipping software to your customers. I am here today to say that anyone who says this, or anything like it, is not only full of crap but indicative of exactly the type of “developer” that has helped to give our industry a bad name.  Here is why: One Who Knows Nothing, Understands Nothing On one hand, you have the cognoscenti of the .NET development world.  Guys like James Avery, Jeremy Miller, Ayende Rahien and Rob Conery; all well-respected and noted programmers that are pretty much our version of celebrities.  These guys write blogs, books, and post videos outlining the "correct" way of writing software to make sure it not only works but is maintainable and extensible and a joy to work with.  They tout the virtues of the SOLID principles, or of using TDD/BDD, or using a mature ORM like NHibernate, Subsonic or even Entity Framework. On the other hand, you have Joe Everyman, Lead Software Developer at Initrode Corporation - in our hypothetical story Joe is the junior developer's new boss.  Joe's been with Initrode for 10 years, starting as the company’s very first programmer and over the years building up a little fiefdom of his own until at the present he’s in charge of all Initrode’s software development.  Joe writes code the same way he always has, without bothering to learn much, if anything.  He looked at NHibernate once and found it was "too hard", so he uses a primitive implementation of the TableDataGateway pattern as a wrapper around SqlClient.SqlConnection and SqlClient.SqlCommand instead of an actual ORM (or, in a better case scenario, has created his own ORM); the thought of using LINQ or Entity Framework or really anything other than his own hastily homebrew solution has never occurred to him.  He doesn't understand TDD and considers “testing” to be using the .NET debugger to step through code, or simply loading up an app and entering some values to see if it works.  He doesn't really understand SOLID, and he doesn't care to.  He's worked as a programmer for years, and that's all that counts.  Right?  WRONG. Who would you rather trust?  Someone with years of experience and who writes books, creates well-known software and is akin to a celebrity, or someone with no credibility outside their own minute environment who throws around their clout and company seniority as the "proof" of their ability?  Joe Everyman may have years of experience at Initrode as a programmer, and says to do things "his way" but someone like Jeremy Miller or Ayende Rahien have years of experience at companies just like Initrode, THEY know ten times more than Joe Everyman knows or could ever hope to know, and THEY say to do things "this way". Here's another way of thinking about it: If you wanted to get into politics and needed advice on the best way to do it, would you rather listen to the mayor of Hicktown, USA or Barack Obama?  One is a small-time nobody while the other is very well-known and, as such, would probably have much more accurate and beneficial advice. NOTE: The selection of Barack Obama as an example in no way, shape, or form suggests a political affiliation or political bent to this post or blog, and no political innuendo should be mistakenly read from it; the intent was merely to compare a small-time persona with a well-known persona in a non-software field.  Feel free to replace the name "Barack Obama" with any well-known Congressman, Senator or US President of your choice. DIY Considered Harmful I will say right now that the homebrew development environment is the WORST one for an aspiring programmer, because it relies on nothing outside it's own little box - no useful skill outside of the small pond.  If you are forced to use some half-baked, homebrew ORM created by your Director of Software, you are not learning anything valuable you can take with you in the future; now, if you plan to stay at Initrode for 10 years like Joe Everyman, this is fine and dandy.  However if, like most of us, you want to advance your career outside a very narrow space you will do more harm than good by sticking it out in an environment where you, to be frank, know better than everybody else because you are aware of alternative and, in almost most cases, better tools for the job.  A junior developer who understands why the SOLID principles are good to follow, or why TDD is beneficial, or who knows that it's better to use NHibernate/Subsonic/EF/LINQ/well-known ORM versus some in-house one knows better than a senior developer with 20 years experience who doesn't understand any of that, plain and simple.  Anyone who disagrees is either a liar, or someone who, just like Joe Everyman, Lead Developer, relies on seniority and tenure rather than adapting their knowledge as things evolve. In many cases, the Joe Everymans of the world act this way out of fear - they cannot possibly fathom that a “junior” could know more than them; after all, they’ve spent 10 or more years in the same company, doing the same job, cranking out the same shoddy software.  And here comes a newbie who hasn’t spent 10+ years doing the same things, with a fresh and often radical take on the craft, and Joe Everyman is afraid he might have to put some real effort into his career again instead of just pointing to his 10 years of service at Initrode as “proof” that he’s good, or that he might have to learn something new to improve; in most cases the problem is Joe Everyman, and by extension Initrode itself, has a mentality of just being “good enough”, and mediocrity is the rule of the day. A Thorn Bush is No Place for a Phoenix My advice is that if you work on a team where they don't use the best practices that some of the most famous developers in our field say is the "right" way to do things (and have legions of people who agree), and YOU are aware of these practices and can see why they work, then LEAVE the company.  Find a company where they DO care about quality, and craftsmanship, otherwise you will never be happy.  There is no point in "dumbing" yourself down to the level of your co-workers and slinging code without care to craftsmanship.  In 95% of these situations there will be no point in bringing it to the attention of Joe Everyman because he won't listen; he might even get upset that someone is trying to "upstage" him and fire the newbie, and replace someone with loads of untapped potential with a drone that will just nod affirmatively and grind out the tasks assigned without question. Find a company that has people smart enough to listen to the "best and brightest", and be happy.  Do not, I repeat, DO NOT waste away in a job working for ignorant people.  At the end of the day software development IS a craft, and a level of craftsmanship is REQUIRED for any serious professional.  When you have knowledgeable people with the credibility to back it up saying one thing, and small-time people who are, to put it bluntly, nobodies in the field saying and doing something totally different because they can't comprehend it, leave the nobodies to their own devices to fade into obscurity.  Work for a company that uses REAL software engineering techniques and really cares about craftsmanship.  The biggest issue affecting our career, and the reason software development has never been the respected, white-collar career it was meant to be, is because hacks and charlatans can pass themselves off as professional programmers without following a lick of good advice from programmers much better at the craft than they are.  These modern day snake-oil salesmen entrench themselves in companies by hoodwinking non-technical businesspeople and customers with their shoddy wares, end up in senior/lead/executive positions, and push their lack of knowledge on everybody unfortunate enough to work with/for/under them, crushing any dissent or voices of reason and change under their tyrannical heel and leaving behind a trail of dismayed and, often, unemployed junior developers who were made examples of to keep up the facade and avoid the shadow of doubt being cast upon them. To sum this up another way: If you surround yourself with learned people, you will learn.  Surround yourself with ignorant people who can't, as the saying goes, see the forest through the trees, and you'll learn nothing of any real value.  There is more to software development than just writing code, and the end goal should not be just "shipping software", it should be shipping software that is extensible, maintainable, and above all else software whose creation has broadened your knowledge in some capacity, even if a minor one.  An eager newbie who knows theory and thirsts for knowledge can easily be moulded and taught the advanced topics, but the same can't be said of someone who only cares about the finish line.  This industry needs more people espousing the benefits of software craftsmanship and proper software engineering techniques, and less Joe Everymans who are unwilling to adapt or foster new ways of thinking. Conclusion - I Cast “Protection from Fire” I am fairly certain this post will spark some controversy and might even invite the flames.  Please keep in mind these are opinions and nothing more.  A little healthy rant and subsequent flamewar can be good for the soul once in a while.  To paraphrase The Godfather: It helps to get rid of the bad blood.

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  • Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

    - by MarkPearl
    Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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  • Is there a distributed project management software like Redmine?

    - by Tobias Kienzler
    I am quite familiar with and love using git, among other reasons due to its distributed nature. Now I'd like to set up some similarly distributed (FOSS) Project Management software with features similar to what Redmine offers, such as Issue & time tracking, milestones Gantt charts, calendar git integration, maybe some automatic linking of commits and issues Wiki (preferably with Mathjax support) Forum, news, notifications Multiple Projects However, I am looking for a solution that does not require a permanently accesible server, i.e. like in git, each user should have their own copy which can be easily synchronized with others. However it should be possible to not have a copy of every Project on every machine. Since trac uses multiple instances for multiple projects anyway, I was considering using that, but I neither know how well it adapts to simply giting the database itself (which would be be easiest way to handle the distribution due to git being used anyway), nor does it include all of Redmine's feature. So, can you recommend me a distributed project management software? If your suggestion is a software that usually runs on a server please include a description of the distribution method (e.g. whether simply putting the data in a git repository would do the trick), and if it's e.g. trac, please mention plugins required to include the features mentioned.

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  • Guest Blog: Secure your applications based on your business model, not your application architecture, by Yaldah Hakim

    - by Darin Pendergraft
    Today’s businesses are looking for new ways to engage their customers, embrace mobile applications, while staying in compliance, improving security and driving down costs.  For many, the solution to that problem is to host their applications with a Cloud Services provider, but concerns that a hosted application will be less secure continue to cause doubt. Oracle is recognized by Gartner as a leader in the User Provisioning and Identity and Access Governance magic quadrants, and has helped thousands of companies worldwide to secure their enterprise applications and identities.  Now those same world class IDM capabilities are available as a managed service, both for enterprise applications, as well has Oracle hosted applications. --- Listen to our IDM in the cloud podcast to hear Yvonne Wilson, Director of the IDM Practice in Cloud Service, explain how Oracle Managed Services provides IDM as a service ---Selecting OracleManaged Cloud Services to deploy and manage Oracle Identity Management Services is a smart business decision for a variety of reasons. Oracle hosted Identity Management infrastructure is deployed securely, resilient to failures, and supported by Oracle experts. In addition, Oracle  Managed Cloud Services monitors customer solutions from several perspectives to ensure they continue to work smoothly over time. Customers gain the benefit of Oracle Identity Management expertise to achieve predictable and effective results for their organization.Customers can select Oracle to host and manage any number of Oracle IDM products as a service as well as other Oracle’s security products, providing a flexible, cost effective alternative to onsite hardware and software costs.Security is a major concern for all organizations- making it increasingly important to partner with a company like Oracle to ensure consistency and a layered approach to security and compliance when selecting a cloud provider.  Oracle Cloud Service makes this possible for our customers by taking away the headache and complexity of managing Identity management infrastructure and other security solutions. For more information:http://www.oracle.com/us/solutions/cloud/managed-cloud-services/overview/index.htmlTwitter-https://twitter.com/OracleCloudZoneFacebook - http://www.facebook.com/OracleCloudComputing

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  • Is it more valuable to double major in Computer Science/Software Engineering or get an undergraduate CS degree with a Masters in SE?

    - by Austin Hyde
    A friend and I (both in college) are currently in a debate over which is better, in terms of employment opportunities, experience, and education: a Bachelors degree in both Computer Science and Software Engineering, or a Bachelors in Computer Science with a Masters in Software Engineering. My point of view is that I would rather go to school for 4-4.5 years to learn both sides of the field, and be out working on real projects gaining real experience, by going the double major route. His point of view is that it would look better to potential employers if he had a Bachelors in CS and Masters in SE. That way, when he's finally done after 4 years of CS and 2-4 of SE (depending on where he goes), he can pretty much have his choosing of what he wants to do. We are both in agreement on the distinction between the two degrees: CS is "traditional" and about the theory of algorithms, data structures, and programming, where SE is the study of the design of software and the implementation of CS theory. So, what's your stance on this debate? Have you gone one route or another? And most importantly, why?

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  • I'm hoping to start an online supermarket and needs advice on open source shopping cart software and applications..

    - by Betterman Simidi
    I have been researching on both open source software and off-the-shelf software for an online supermarket project in Africa. I have now narrowed by search to X-cart and the PHP based PrestaShop shopping carts. My plan is to acquire an open source shopping cart either by purchasing or as a free open source cart and hire a local developer to customize it to our local needs. I have been doing the demo for x-cart for three weeks now and had thought it might work best for us but after going through the 600 page manual and I'm concerned with how far it can be localized. Yesterday i was looking at the possible Prestashop free open source cart and i seem to like the back-end. Didn't like the back-end for Magento much but from reviews conducted by third-parties they seem to recommend it. I'm now wondering whether i should have a developer start the whole project from scratch, or use an open source software such us PrestaShop or get x-cart which can then be customized. Note that my store will have thousands of products and services including groceries and so i want something that can handle upto 500,000 products and over. Kindly advice. 93276

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  • Is there such a thing as "closure" with software work?

    - by Bobby Tables
    I burned out last year (after a decade of fulltime programming jobs) and am on a sabbatical now. With all the self-examination I've started to figure out some of the root causes of my burnout, and one of the major ones is basically this: there was never any real closure in any of the work I've ever done. It was always a case of getting into an open-ended support/maintenance grind and going stale. When I first entered the industry, I had this image of programming work being very project-based. And I expected projects to have a start, beginning, and END. And then you move on and start on something totally new and fresh. Basically I never expected that a lot (most) of software work involves supporting and maintaining the same code base for open-ended long periods of time - years and even decades. That, combined with generally having itchy feet makes me think that burnout is inevitable for me, after 2-3 years, in ANY fulltime software job. All this sounds like I probably should have been a contractor instead of a fulltimer. But when I discuss this with people, a lot of them say that even THEN you can't really escape having to go back and maintain/support the stuff you worked on, over and over (eg. Coming back on support contracts, for example). The nature of software work is simply like that. There is no project closure, unlike in many other engineering fields. So my question is - Is there ANY programming work out there which is based on short to mid term projects/stints and then moving on cleanly? And is there any particular industry domain or specialization where this kind of project work is typical?

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  • Are there currently any modern, standardized, aptitude test for software engineering?

    - by Matthew Patrick Cashatt
    Background I am a working software engineer who is in the midst of seeking out a new contract for the next year or so. In my search, I am enduring several absurd technical interviews as indicated by this popular question I asked earlier today. Even if the questions I was being asked weren't almost always absurd, I would be tired nonetheless of answering them many times over for various contract opportunities. So this got me thinking that having a standardized exam that working software professionals could take would provide a common scorecard that could be referenced by interviewers in lieu of absurd technical interview questions (i.e. nerd hazing). Question Is there a standardized software engineering aptitude test (SEAT??) available for working professionals to take? If there isn't a such an exam out there, what questions or topics should be covered? An additional thought Please keep in mind, if suggesting a question or topic, to focus on questions or topics that would be relevant to contemporary development practices and realistic needs in the workforce as that would be the point of a standard aptitude test. In other words, no clown traversal questions.

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  • FREE three days of online SharePoint 2010 development training for UK software houses Feb 9th to 11th

    - by Eric Nelson
    I have been working to get a SharePoint development course delivered online in February and March – online means lots of opportunities to ask questions. The first dates are now in place. The training is being delivered as a benefit for companies signed up to Microsoft Platform Ready. It is intended for UK based companies who develop software products* Agenda: Day 1 (Live Meeting 3 hours) 1:30 - 4:30 •         Getting Started with SharePoint: Understand why and how to start developing for SharePoint 2010 •         SharePoint 2010 Developer Roadmap:  Explore the new capabilities and features •         UI Enhancements: How to take advantage of the many UI enhancements including the fluent UI ribbon and  extensible dialog system. Day 2 (Live Meeting 3 hours) 1:30 - 4:30 •         Visual Studio 2010 Tools for SharePoint 2010: Overview of the project and item templates and a walkthrough of the designers •         Sandboxed Solutions: The new deployment model can help mitigate the risk of deploying custom code   •         LINQ to SharePoint:  SharePoint now fully supports LINQ for querying lists Day 3 (Live Meeting 3 hours) 1:30 - 4:30 •         Client Object Model: The Client OM can be accessed via web services, via a client (JavaScript) API, and via REST •         Accessing External Data: Business Connectivity Services (BCS) enables integration with back end systems •         Workflow: A powerful mechanism to create functionality using Windows Workflow Foundation Register for FREE (and tell your colleagues – we have a pretty decent capacity) To take advantage of this you need to: Sign your company up to Microsoft Platform Ready and record your SharePoint interest against one of your companies products Read about Microsoft Platform Ready Navigate to the “Get Technical Benefits” tab for SharePoint and click on Register Today You will then ultimately get an email with details of the Live Meeting to join on the 9th. But you should also favourite the team blog for any last minute details * Such companies are often referred to as an Independent Software Vendors. My team is focused on companies that create products used by many other companies or individuals. That could be a packaged product you can buy "off the shelf" or a Web Site offering a service - the definition is actually pretty wide these days :-) What it does not include is a company building software which will only be used by its own people.

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  • When can I publish a software tool written at work?

    - by AlexMA
    I'm working on a software problem at work that is fairly generic, but I can't find a library I like to solve it, so I'm considering writing one myself (at least a bare-bones version). I'll be writing some if not all of the 1.0 version at work, since I need it for the project. If turns out well I might want to bring the work home and polish it up just for fun, and maybe release it as an open-source project. However, I'm concerned that if I wrote the 1.0 version at work I may not be allowed to do this from a legal sense. Obviously I could ask my boss (who probably won't care), but I'm curious how other programmers have dealt with this issue and where the law stands here. My one sentence question is, When is it okay (legally/ethically) to open-source a software tool originally written by you for work at work? What if you have expanded the original source significantly during off-hours? Follow-up: Suppose I write the whole thing at home on my time then simply use it at work, does that change things drastically? Follow-up 2: Note that I'm not trying to rip off my employer (I understand that they're paying me to build products that they own)--I'm just wondering if there's a fair way of doing this for all involved... It would be nice if some nonprofit down the road could use my code and save them some time. Also, there's another issue at stake. If I write the library for a very simple, generic thing (like HTML tables in Javascript), does that mean I can never again do so on my own time without putting myself at legal risk (even if it was a whole new fresh rewrite or a segment of a larger project). Am I surrendering my right to write code for this sort of project for the rest of my life (without this company's permission), since the code at work might still be somewhere in my brain influencing me? This seems related to software patents, as a side-note.

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  • In which fields does quality of the software product matter as much as the completion time?

    - by Nav
    Someone told me that if the software product meets clients expectations, it is good quality. But I've worked with Interaction Designers (the same kind of people who made Gmail's interface and usability so cool!), and I've loved working with them because even though they came up with hundreds of changes in requirements, and emphasised on many many subtle details, when the software was complete, I could look at the product and say WOW! The current place I work, the only thing that matters is completing the project on time. As long as it works and as long as the client says it's ok, nobody bothers to improve it. I'm not talking about gold-plating, but I believe that for a programmer to enjoy his (well, maybe her too ;) ) job, they should be able to proudly say that "Hey, I made that software" and that comes only when the product is of good quality. Apart from your opinions on this, I'd also like to know which fields (Eg. Aerospace, Finance etc.) could I find companies (or you could mention the company name) where the quality of a product is as important as completing the project on time?

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  • How can we best petition to bring Adobe creative software to Ubuntu?

    - by Sixthlaw
    Now I know its not as simple as asking for Adobe to support their design software on Ubuntu, but is there a way for the community and Canonical to make known to Adobe the rapidly growing amount of Linux users, and their desire for this great set of tools OFFICIALLY? I know that many of the answers I receive might be of the fashion "Its not going to happen", "use the free tools provided" or "Who knows it might happen in the near future", but this IS not what I am looking for. I have noticed, on sites like www.OmgUbuntu.com, there are links to pages where people can "like" the idea. Is there a way to try and get the whole community on board with this one, even Canonical, and as stated above, put forward this proposal to Adobe. The current requests for an Adobe CS, for Linux, are in dribs and drabs scattered all of the internet. Now is the best time to come up with productive solutions on how we can best gather statistics on the amount of people willing to buy the Adobe CS. These are the words of an Adobe employee: "I have forwarded this feedback on to the appropriate team who will consider it for future releases of Adobe software." The larger amount of people we have unified in the ONE community proposal, the greater chance we have of getting the software. How can we make this happen?

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  • Is embedded programming closer to electrical engineering or software development?

    - by Jeremy Heiler
    I am being approached with a job for writing embedded C on micro controllers. At first I would have thought that embedding programming is to low on the software stack for me, but maybe I am thinking about it wrong. Normally I would have shrugged off an opportunity to write embedded code, as I don't consider myself an electrical engineer. Is this a bad assumption? Am I able to write interesting and useful software for embedded systems, or will I kick myself for dropping too low on the software stack? I went to school for computer science and really enjoyed writing a compiler, managing concurrent algorithms, designing data structures, and developing frameworks. However, I am currently employed as a Flex developer, which doesn't scream the interesting things I just described. (I currently deal with issues like: "this check box needs to be 4 pixels to the left" and "this date is formatted wrong".) I appreciate everyone's input. I know I have to make the decision for myself, I just would like some clarification on what it means to be a embedded programmer, and if it fits what I find to be interesting.

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  • Which metric/list should be used to evaluate whole software development team?

    - by adt
    Title might be seem vague, so let me tell you a little bit history what i am trying to clarify question. I have been hired as a consultant for a corporate's small developement divison ( The company also owns a couple of software dev. companies) My ex manager runs a BI team, with reportes, analyts and developers. He asked me to evaluate overall design, software developement process and code quality . Here what i found, Lots of copy/paste code everywhere ( no reuse ) Even though they have everything TFS, VS Ultimate etc, No Build process , No Cruise Control.net / team city... No unit tests Web Pages with 3700 lines of code, Lots of huge functions ( which can be divided into smaller one's ) No naming convention both db and c# code No 3r party or open source project No IoC No Seperation Of Concerns No Code Quality Check ( NDepend or FxCope or nothing ) No Code Review No Communication within the team They claim they wrote an application framework ( 6 months 3 persons), but I would hardly call a framework ( of course no unit test, there are some but all commented out). Framework contains 14 projects but there are some projects with 1 file 20 lines of code . Honestly, what people are doing fixing bug all thr day( which will provide more bugs eventually), they are kind of isolated from community, some team members even dont know github or stackoverflow they probably went there with google but they dont know about it. So here is question, Is This list ok ? Or am i being picky? Since I dont have any grudge against them, I just want to be fair, honest and I would like to hear you suggestions, before I would submit this list. And since this list also will be review by software division's manager, I dont want any heart break or something like this. http://www.hanselman.com/altnetgeekcode/ For example I would love to such lists, i cant make references. Thanks in advance.

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