Well ! I got te answer of the first question :
"They said a checkpoint is written every 10 mn. Is that true for every project done ?"
No, it is not :
http://www.worldcommunitygrid.org/forums/wcg/...=11332&offset=0#84461

But who can answer to the two last questions ?

Actually just reviewed a checkpoint log for GC jobs on 2 different systems. The frequency seems pretty much independent of CPU speed and does save so every 20 minutes. Have accordingly amended the above referenced post in the 'Start Here' forum.

If u properly close down the system, best first exiting the agent, than follow the OS shutdown routine rather than the power switch, the loss of work progress should be limited.

The job that was in progress will be resumed from the last checkpoint saved before closing.

Deadlines:

The deadlines vary as the ones controlling the distribution are playing with the number to optimize the use of the BOINC buffer function:

For BOINC the initial distribution deadline is presently 9 days for most all jobs. For extra copies it can be 1-4 days depending on urgency (they go automatically to 'reliable' regular clients).

Late returns can result in credit, but are waste because right on the original deadline a new copy is send out to someone else, thus duplicating work. If the extra copy is back before the original being returned late, no credit is given.

Time-Out for UD is 3 weeks wall-clock (seen in main page of agent) or 2 weeks CPU time, which ever comes first. There is a longer grace of 2 months from original dispatch..... yes UD crunchers who process very infrequent do occasionally take that long. It used to be 3 months, but that was cut down in early 2007 to free-up disk space and speed up batch completion.

Thus is the present standing on deadlines that i know off.

As for as shut down after a project completion, that has been discussed before on this forum. It's not build in on the BOINC developers wishlist, page 99 and absolutely low priority...... it's a case of very low demand. You can use a third party scheduler and anyway, once a job is finished, BOINC uses little to nothing in RAM space and zero in CPU time.