Work units too large


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Questions and Answers : Wish list : Work units too large

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Alcator
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Czech Republic
Message 907522 - Posted: 14 Jun 2009, 7:44:42 UTC

Hello,

2 years ago, I participated in SETI@home, and it worked just fine -- units took my computer (1 CPU, 1 GB RAM, WinXP) an hour or two to complete.

Now, I have a 2 core 2 GB WinVista machine, but units tell me they will need 200+ hours to complete.

What happened with SETI? If a unit has to be delivered in 3 weeks' time, I am unable to have BOINC work as long as would be needed. 200+ hours per unit??

Or am I doing something wrong?
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Profile Gundolf Jahn
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Germany
Message 907536 - Posted: 14 Jun 2009, 8:46:14 UTC - in response to Message 907522.

I copied your message title to the search box in the upper left corner of this page and got: Work units are too large. Look there for answers.

Gruß,
Gundolf
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Computer sind nicht alles im Leben. (Kleiner Scherz)

SETI@home classic workunits 3,758
SETI@home classic CPU time 66,520 hours

Aurora Borealis
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Message 907553 - Posted: 14 Jun 2009, 10:36:14 UTC
Last modified: 14 Jun 2009, 10:40:08 UTC

The WU (Work Unit) you received are Astropulse. The project now consist of two type of search's. One is similar to the original narrow band search and referred to as MultiBeam Seti Enhanced (MB) WU, they take under 10 hrs to process. The other is a wide band search called Astropulse (AP) WU. These can take about 60-80 hrs on your type of system, but also have a longer due date of a month.

Boinc is very conservative on the initial estimate of completion times hence the 200 hrs. This is to ensure you don't download more work that can be completed on time. As Boinc learns your system capabilities over a period of time, it uses a value called Duration Correction Factor (DCF) to adjust and more accurately estimated completion time.

It you feel that you only want to get the shorter MB WU you can deselect Astropulse in the SETI@home preferences of your account.

An other option is to use third party optimized applications. These are CPU capability specific and can cut processing time by half but require a more hands-on participation by the users. These need to be manually installed and maintained as Boinc can't update them automatically. The user is required to more closely follow project developments to know when the software is updated. There are post concerning this in the Number Crunching forum.
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Boinc V7.0.27
Win7 i5 3.33G 4GB, GTX470

OzzFan
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Message 907591 - Posted: 14 Jun 2009, 15:27:30 UTC - in response to Message 907522.

Hello,

2 years ago, I participated in SETI@home, and it worked just fine -- units took my computer (1 CPU, 1 GB RAM, WinXP) an hour or two to complete.

Now, I have a 2 core 2 GB WinVista machine, but units tell me they will need 200+ hours to complete.

What happened with SETI? If a unit has to be delivered in 3 weeks' time, I am unable to have BOINC work as long as would be needed. 200+ hours per unit??

Or am I doing something wrong?


Just as progress has allowed you to buy faster computers, progress has also allowed SETI@Home to use different search methods for finding ETI. The new workunits, which are looking for broadband signals, as opposed to the older SETI workunits which are looking for narrowband signals, take much longer to process because of this advancement.

The good news is that you have two possibble options: you can attempt to let your computer finish the AstroPulse workunit, and if it doesn't finish on time, BOINC will take note of this and hardly send you any new ones (because of the calculations used in BOINC, one may appear from time to time). Or, if you want to ensure that you never receive one of these longer, more advanced units, there is an option in your preferences to turn it off completely.

Personally, I think you should give your computers a chance to finish them, because as Aurora said, the estimation is usually far off on new installations and Intel chips finish them within 40 hours on average. Though if you prefer to disable AstroPulse altogether, I can provide you with directions on how to do so.
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Questions and Answers : Wish list : Work units too large

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