Understanding tasks

Questions and Answers : Getting started : Understanding tasks
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Matthew@SETI@home

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Message 1765573 - Posted: 17 Feb 2016, 0:23:35 UTC

I've read the BOINC documentation, but I still don't understand tasks. On my list of tasks http://setiathome.berkeley.edu/results.php?userid=10276369, there are 8 tasks listed for the first computer 7934995. All 8 tasks show "In progress". Does this mean the computer is dividing its time between 8 different work units?

If so, why? That wouldn't increase total throughput.

If only some of those tasks are currently being worked on, how can I see which ones they are if they have the same Status as the rest?
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rob smithProject Donor
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Message 1765639 - Posted: 17 Feb 2016, 6:01:09 UTC
Last modified: 17 Feb 2016, 6:03:43 UTC

The server (which is where the website gets data from) knows it has sent the tasks to you, it does not know if they are running, or sitting waiting to run, thus is calls them "in progress". Once they've finished and have been reported they move to "pending validation", then to "valid" (the one we all like), "validation inconclusive" (not so nice)or "error" (there's something wrong somewhere).

To see what's actually happening on your computer you have to be actually connected to that computer - easiest at the outset sat in front of it - there are other (remote) ways. If you look at the BOINC manager's "advanced" view you will see which tasks are actually running, ready to run (but haven't started yet), "waiting to run" (started but have stopped to let another tasks run), "ready to report" (finished and the results file sent back). Tasks that have reported are no longer on your computer so don't show on BOINC manager.
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Message 1765719 - Posted: 17 Feb 2016, 15:14:10 UTC - in response to Message 1765639.  

Thanks for the reply. It didn't occur to me that the computer would not necessarily report to the server when it started a work unit.

As a career software designer/developer, I'm highly impressed by BOINC. It's both highly reliable and bug-free and incredibly easy for the end-user. Software jobs this well done are not very common.

Another question, and let me know if it's preferred to start a new thread when the new question is outside the scope of the thread's title.

"Results" seem to be something countable, but they don't appear to correspond 1-for-1 with work units. What is a "result"?
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Message 1765722 - Posted: 17 Feb 2016, 15:37:05 UTC

Your second question is really a continuation of the first.

As I never bother trying to correlate the "results" and "tasks" I've no real idea what they are meant to be, that is apart from "confusing"....
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Message 1765739 - Posted: 17 Feb 2016, 16:52:45 UTC

The project splits work from the main data drives, these are called workunits.

Each workunit is split into two identical tasks, which are sent to two individual computer hosts that people have added through BOINC to the project.

Both of the hosts crunch the data in the task and the outcome of those calculations is a small result file that gets uploaded back to the project. It holds information on what task it was (name, AR, etc), which hostID calculated the data and the outcome of that data.

The reporting done separately is to tell the database that the task was crunched and the result file was uploaded to the server, and that this task is no longer waiting or ready to run, and that if the host is eligible, it should receive more work to fill up the cache.
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Message 1765869 - Posted: 17 Feb 2016, 23:42:01 UTC - in response to Message 1765719.  

"Results" seem to be something countable, but they don't appear to correspond 1-for-1 with work units. What is a "result"?

Only people at the lab like to call tasks "Results" (even if the task is still not sent to anybody)
See the explanations on the bottom of this page:
http://setiathome.berkeley.edu/sah_status.html

e.g.:
"Results ready to send: For each workunit, results are generated that are then sent out to individual users to be executed"

... should be read as:
"Tasks ready to send: For each workunit, tasks are generated that are then sent out to individual users to be executed"

But "Results returned and awaiting validation" are really "Results" - task was computed and Result file sent back to server


A "task" is one copy of the "Workunit", at least 2 tasks are generated from 1 Workunit so the 2 Result files can be compared - some computers are not reliable and produce wrong numbers (heat, Overclock, low voltage, ...)

All tasks from the same Workunit are identical data files.



- ALF - "Find out what you don't do well ..... then don't do it!" :)
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Questions and Answers : Getting started : Understanding tasks


 
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