problem about distributed-computing-Collection of common programming errors


  • Anup Saumithri
    ubuntu hadoop cluster-computing distributed-computing
    This may be a silly question. I confess I am totally new to hadoop, so please bear with me.But,Is it possible to emulate master nodes for NameNode & JobTracker and multiple slave nodes for DataNode & TaskTracker on a single ubuntu installation without having to have multiple laptops/computers?Is there anyway I can emulate multiple nodes for a fully distributed hadoop operation on a single ubuntu installation?Again I apologize if there are logical flaws &| factual inaccuracies in my q

  • Book Of Zeus
    distributed-computing distributed-system
    I am doing with a friend of mine a system to implement a reliable multi cast library. We are dealing with many processes belonging to a group; any process can join or leave the group. If one sends a message, this is delivered by all the others.We would like to handle the sender’s crash so that when this happens, either all or none of the recipients deliver the message.Can you suggest a good strategy (algorithm) to handle the part about all or nothing?

  • karthik A
    client-server distributed-computing
    The following text says this which I’m not able to quite agree :client C sends a request R to server S. The time taken by a communication link to transport R over the link is D. P is the maximum time needed by S to recieve , process and reply to R. If omission failure is assumed ; then if no reply to R is received within 2(D+P) , then C will never recieve a reply to R . Why is the time here 2(D+P). As I understand shouldn’t it be 2D+P ?

  • Wesley Bland

  • David Heffernan
    delphi com client-server distributed-computing
    In a Client / Server environment, where the server implements the COM interface, there are cases where the connection is lost for some reason (client crashes), but the instance of the thread it stays active on the server, consuming memory until the application is finalized . There are some way to destroy the instances inactive by the server?Server using TRemoteDataModule and client TDComConnection.

  • grawity
    windows windows-services daemon distributed-computing
    I want to manage the startup / re-start and shutdown of a multi module software system running on a set of windows machines.For example: [some machines booted, some still doing so] run the whole system using a startup-process or a network command etc. an the operator station computer – all machines shall start it’s defined processes some processes may crash during operation – if defined, they shall be restarted silently stop the whole system using a stop-process or a network command etc. an the

  • Chris Sears
    process locking monitoring distributed-computing
    I have a distributed app where resources get locked for exclusive use by tasks. Each task runs in its own process. I’d like to automatically unlock resources if a task process exits or the server it’s running on dies (eg power failure).How could I remotely detect such a process exit/failure within a few seconds?After some Googling I came up with a few ideas, but I don’t have direct experience with any of them…Use advisory lock functions built into mySQL (get_lock) or postgres (pg_advisory_lock

  • Frank Shearar
    distributed-computing message-queue
    I am trying to learn more about the various ways that the problem of a Distributed Queue may be solved. So I would like know what products, services, implementations and research papers that are already out there.An implementation will face many challenges and will be forced to make tradeoffs:Does it have strong or loose ordering? Does it have idempotent put? Can we have more queues than what can fit on a single machine? Can we have more data in a queue than what can fit on a single machine? How

  • user86928
    web-services rest distributed-computing
    Recently completed a project for handling credit card processing. One of the difficulties I faced was handling the delay / possible failure of notification messages. The most complex example was:an external system sending the request for payment my system turning that request into a request to the payment gateway sending the user to the gateway waiting for the user to perform payment the user returning back to my system but being held until the system receives notification of success/failure Sen

  • TemporaryNickName
    c++ distributed-computing chrome
    I am wondering what is the purpose of Chrome using multiple processes for each tabs? I asked this to C++ chat room and one responded it is a product of laziness. I personally believe this is an example of “Distributed processing” like in Erlang programming language. What exactly is it?

  • skaffman
    java distributed-computing javaspaces
    I have great doubts about this forum, but I am willing to be pleasantly surprised 😉 Kudos and great karma to those who get me back on track.I am attempting to use the blitz implementation of JavaSpaces (http://www.dancres.org/blitz/blitz_js.html) to implement the ComputeFarm example provided at http://today.java.net/pub/a/today/2005/04/21/farm.htmlThe in memory example works fine, but whenever I attempt to use the blitz out-of-box implementation i get the following error:(yes com.sun.jini.mahal

  • Yellow Duck
    java tomcat permissions rmi distributed-computing
    I am having some difficulties with RMI and Tomcat. This is the big picture of this project I am working on: the RMI client is called by a Java servlet that runs in Tomcat, the servlet accept user input and pass the parameters to the RMI client. Then the RMI client then calls the RMI server to run the heavy compuation part. The problem is that although everything works fine without hosting the RMI client in the Tomcat server, it doesn’t run once I put it in Tomcat. Here are some configurations: I

  • Chris Zheng
    hadoop distributed kerberos distributed-computing
    I am configuring hadoop on clusters.All node started successfully, but secondary node failed doCheckpoint with following log:2011-10-25 11:09:07,207 ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Exception in doCheckpoint: 2011-10-25 11:09:07,208 ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: java.io.IOException: Server returned HTTP response code: 403 for URL: https://name.node.http:50470/getimage?getimage=1at sun.reflect.GeneratedConstructorAccessor24.newInst

  • happy
    java rmi distributed-computing
    I have created below bat file to run my RMI server@echo Offset classpath=C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\RMI_Server\bin\; set classpath=C:\policy.all; set classpath=C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\RMI_Server\log4j-1.2.12.jar; set classpath=C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\RMI_Server\log4j-1.2.15.jar; set classpath=C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\RMI_Server\log4j.jar; set cla

  • user268915
    java networking rmi distributed-computing
    My goal is to create a Distributed computing program that launches a server and client at the same time. I need it to be able to install on a couple of machines and have all the machines communicating with each other, i.e. Master node and 5 slave nodes all from one application.My problem is that I cannot properly use unicastRef, I’m thinking that it is a problem with launching everything on the same port, is there a better way I am overlooking?this is part of my code (the part that matters)try {