This thread is intended to help users who have just received a sulphur WU and just realised that it is a lot longer than their previous slab WU.

You may be wondering whether to keep it or not, and this thread is to help you make up your mind on that. This thread may also help people who are currently crunching slabs to decide whether to set nomorework in order to avodi sulphur, or to allowmorework in order to accept sulphur when they get their next WU.

There is an already-long thread here discussing what the project could/should offer as well as the new sulphur WU. If you want to comment about the project\'s decision to withdraw slab, please take those comments to that thread. This thread is simply to help you decide whether to abort the new sulphur WU or to allow it to run.

First off, if you do decide not to keep the sulphur WU, it is kinder to the project to abort than to detach without an abort. The best procedure is

1. Set nomorework for CPDN
2. Abort the sulphur WU
3. In the work tab, wait for it to change from \"Aborted by user\" to \"computation error\"
4. Update CPDN
5. In the work tab, wait for the WU to disappear
6. Either stay attached but with nomnorework; or detach.

I can\'t tell you how to make the decision -- like all donors to all BOINC projects you are volunteers and free to make your own choices. I do suggest that you think about the following points before making up your mind where you personally want to strike the balance.

The points numbered A1, A2,... are points in favour of aborting sulphur, those numbered C1, C2, ... in favour of crunching it.

A1. The run time will be about three times as long as a slab model

A2. This might mean you run over the deadline

A3. A1 might be an issue on a loan machine, or where you have permission from another person/organization to run the software on their box

A4. A1 also means that the potential amount of lost science (after a machine failure, theft, etc) is up to three times as great

A5. You are more likely to go into EDF / NWF modes

A6. A5 means that CPDN will hog the box for months on end. For the next few of months your RAC will be skewed towards CPDN, followed by months when it is skewed away from CPDN while the long term debt mechanism hold CPDN back and lets your other projects catch up.

A7. A5 also means that CPDN is suddenly less suitable for being a \'background\' project to cover gaps in work from projects like LHC which have frequent fallow times. When the work on LHC comes back, if your box is in NWF it will not look for it. Then when the sulphur finishes, LHC might be in another fallow period so you will download another sulphur

A8. On an HT box you might be running two WU together as this gets around 30% more throughput at the expense of around 45% more runtime. On some boxes that are on part-time, you may want to abort one sulphur and fall back to single CPU running to keep the runtime more manageable.

On the positive side

C1. Yes the run is longer but the credits are in proportion. If you trickle regularly you should see around the same RAC as at present.

C2. On this project the deadlines are advisory. You will not lose credit for runing over, and the scientists seem content to get the results late in preference to not at all.

C3. The sulphur science is exciting science and an important part of the effort to understand how the atmosphere works, and if it takes longer then you may want to accept that it just does and stay with the project

C4. If regretably something prevents the WU from finishing, you would keep the credit accumultaed in your trickles even if there is nothing for the science

C5. Sulphur is all the project is currently offering (on BOINC anyhow) and you may feel strongly that you want to continue supporting this project.


Those are my thoughts: please add any other A\'s or C\'s ?

best regards and happy BOINCing whether you go or stay.

And if you go, please check back every month or so as I for one am hoping the scientists & programmers will figure out something useful to do for those of us wanting slab-sized work units -- but those issues are for the other thread, please.

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