*** MyGrid Release 2.2.x FAQ ***


+ WHAT IS THE DIFFERENCE BETWEEN MyGrid and OurGrid ?

     MyGrid is a broker that provides a set of scheduling and
     application execution cycle monitoring. OurGrid is a P2P network
     for resource sharing. The idea is that MyGrid request grid
     machines to OurGrid peer that gains acces to resources on demand
     by negotiating with other peers. More details at publications
     page at OurGrid Project site (http://www.ourgrid.org).


+ WHAT IS A Grid Description File ? WHERE SHOULD IT BE PLACED ?

     The Grid Description File is a simple file created by the user to
     inform Home Machine how to communicate with the Grid Machines. It
     is because the communication can be different for each one of the
     Grid Machines. You can have several Grid Description Files. 

     Since "mygrid addgum" can be invoked from any directory, it does
     not matter where the "Grid Description Files" are kept. 


+ WHAT IS A Job Description File ? WHERE SHOULD IT BE PLACED ?

     The Job Description File is a simple file created to describe a
     set of tasks that form a job. See more details about Job
     Description File format in the Manual (http://www.ourgrid.org).
     You can have several Job Description Files.

     Since "mygrid addjob" can be invoked from any directory, it does
     not matter where the "Job Description Files" are kept. 


+ WHILE MY APPLICATION IS RUNNING SOME FILES NAMED mygrid-xxxx ARE
CREATED. WHY DOES THIS HAPPEN ?

     These files are generated every time MyGrid is executed for
     debugging purpose, so you can follow local and remote commands
     that MyGrid tries to execute and if an error occurs you can
     identify and correct it.

     In order to avoid the creation of these files, you must turn off
     "MG.debug" option in your "~/.mygrid/MG.properties" file.


+ HOW CAN I KNOW IF THE TCP PORT IS ALREADY IN USE ?

     There are two diferent ways to find out if a TCP port is being
     used by another service on a given machine.

     a) netstat -pa | grep <portNumber>

	This command shows the services listening on <portNumber>
	port, if there are no services listening on this port, nothing
	will be displayed.

     b) telnet <hostname> <portNumber>

	If the connection can be established, there is a service
	listening on the port. 


+ HOW CAN I INSTALL A NEWER VERSION OF MyGrid IF I ALREADY HAVEA
PREVIOUS VERSION INSTALLED ON MY MACHINE ?

     It is very simple to install a newer version of MyGrid. You just
     need to unpack the tarball file into another directory. Before
     starting to use the newer version you will need to stop any User
     Agent still running on any Grid Machine. 

+ WHEN I AM RUNNING MyGrid MY COMPUTER STOPS RUNNING NEW WINDOWS. WHAT
IS WRONG ?

     In some situations, the X security system can cause a temporary
     failure opening new windows. This problem occurs because too many
     connections are opened to perform User Agent's auto installation
     and/or User Agent's auto start. If you are using ssh, one
     solution is to run: ssh -x <machine>, for example: ssh -x
     warlock.lsd.ufcg.edu.br. Done that, you'll be able to open
     applications remotely, using ssh, and see the application results
     as if it were running locally.

+ WHAT ARE THE REASONS OF A TASK FAILURE ?

     A task may fail for many reasons. 

     a) when the processor assigned to the task becomes
     inactive during its execution; 
     
     b) when all files needed to its execution were not transferred to
     the grid machine;

     c) when there were errors during the execution of the scripts
     called by the INIT or FINAL fields in the Job Description File.

+ HOW TO IMPROVE MY FEEDBACK FROM e-MAIL LISTS ?

     In this link you can find several tips about how to proceed smart
     when asking questions on forums, newsgroups and e-mail lists.

     How To Ask Questions The Smart Way - Before You Ask
     http://www.catb.org/~esr/faqs/smart-questions.html#before