Changes between Version 4 and Version 5 of JobIntro

Timestamp:

Apr 12, 2014, 1:10:34 PM (10 years ago)

Author:

davea

Comment:

--

JobIntro

@@ -1 +1 @@
 = Introduction to job processing =
 
-Most distributed processing systems let you submit jobs -
-you supply an executable and some input files,
-and the system runs the job on a remote computer and
+In conventional distributed processing systems a job consists of
+an executable and some input files.
+The system runs the job on a remote computer and
 gives you the output files when it's done.
+
 You can do this type of [SingleJob single job submission] in BOINC.
-
-However, BOINC is designed for different types of situation, in particular those where:
+However, BOINC is designed for situations where
 
  * You need to process thousands or millions of jobs, using only a few applications.
  * You want jobs to be '''platform-independent''', i.e. you don't have to specify what kind of computer to use.
- * You want job results to be validated by replication.
+ * You don't trust remote computers, so you want to to "validate" their results.
 
 To handle these requirements, BOINC defines an architecture
-in which jobs are processed in a pipeline consisting
-of the following programs:
+in which jobs are processed in a pipeline consisting of the following steps:
 
- * A '''work generator''' creates jobs.
- * A '''validator''' compares replicated results and selects one of them as 'canonical', or correct.
- * An '''assimilator''' handles validated results, storing them in an archive or database.
+ * You submit jobs.
+ * The jobs are executed on remote hosts.
+    In some cases, jobs may be "replicated", i.e. executed on multiple hosts.
+ * A [ValidationIntro '''validator'''] examines replicas and selects one of them as 'canonical', or correct.
+ * An [AssimilateIntro '''assimilator'''] handles validated results, storing them in an archive or database.
 
-Typically these programs are application-specific,
-and you will need to develop them (usually in C++) using
+Typically validators and assimilators are application-specific,
+and you'll need to develop them (usually in C++) using
 frameworks supplied by BOINC.
 In some cases you may be able to use sample versions that are part of BOINC.
 Each program should be listed as a [ProjectDaemons daemon] in the [ProjectConfigFile config.xml] file.
 
-== Submitting jobs locally ==
+== Submitting jobs ==
 
-To submit a job:
+To set up for submitting jobs, you must
 
+ 1. Create an [XaddTool app] and [AppVersionNew app versions].
  1. Write XML [JobTemplates template files] that describe the job's input and output files
   (typically the same template files can be used for many jobs).
- 1. [JobStage Stage] the job's input file(s)
- 1. Invoke a [JobSubmission BOINC function or script] that submits the job.
+ 1. Set up a validator and assimilator for the application.
+
+Then, for each job, you must
+ 1. Stage the job's input file(s) on the BOINC server.
+ 1. Submit the job, using any of several methods (see below).
 
 Once this is done, BOINC takes over: it creates one or more instances of the job,
 distributes them to client hosts, collects the output files.
-It [ValidationIntro validates] and
-[AssimilateIntro processes] the results,
-and deletes the input and output files.
+It validates and assimilates the results, and deletes the input and output files.
 
-Steps 2) and 3) may be done by a [WorkGeneration work generator] program
-that creates lots of jobs.
+=== Local submission ===
 
-== Submitting jobs remotely ==
+In this approach, jobs are submitted by programs or scripts run on the BOINC server.
+The job submitter, of course, must have login access to the server.
 
-Submitting jobs locally requires being logged in to the BOINC server.
-In some cases you may want to allow jobs to be submitted
-without logging in - e.g., via a web interface.
-This is discussed [RemoteOverview here].
+=== Web-based submission ===
+
+In this approach, jobs are submitted via web pages running on the BOINC server.
+The job submitter need not have login access to the server.
+
+=== Remote submission ===
+
+In this approach, jobs are submitted by programs or web pages running
+outside the BOINC server.