Hi, this is my first post and I know almost nothing about BOINC, so forgive me if this is some obvious question.

I installed BOINC from a .deb package on Ubuntu Feisty 32-bit, and it looks nice and it claims to be working away on tasks (on project Tanpaku), then I hit "suspend" on the two tasks queued and shut the machine down to go to bed.

When I started up today, I could see the completion at ~54% on the first task and resumed it, but it started from 0%... what's that about? Does the actual core daemon have to be shutdown specially or it corrupts the work done or something?

Im guessing it hadn't checkpointed yet. Some projects like RCN are notorious for it. If you shutdown and its not finished you get to start again. Try and find a project that checkpoints often or leave the computer on are your only options.
Actually ill add another which is beg your chosen project to add checkpointing. The issue here is with the science application supplied by the project so best to ask on the project boards. i dont run the project so i cant confirm it doesnt checkpoint.

Or you can do what Clownius suggested and find a project that checkpoints frequently and reliably, there are many.

EDIT ADDED: Note that if you hibernate then you don't need to shutdown BOINC properly as Sekerob suggested. Also, I just realised you are on Linux not Windows but the above info may give you some helpful ideas anyway.

Thanks guys, I see now. It would be nice if perhaps hitting "suspend" could force the project to checkpoint immediately, but I suppose it might be project-specific and not within the mandate of the BOINC manager/core itself.

Yeah, putting the machine to S4 sleep sounds like a good idea, since it doesn't use much power, but I haven't experimented with any ACPI sleep states since a few kernels ago. It's still dodgily implemented in hardware and tends to assume that the running OS is Windows.

Dodgy implementation is my understanding too but I'm not a Linux expert. There may be a way around it all. You can use the boinc-cmd executable to access the RPC interface in scripts. I am almost certain you could detect either a checkpoint or work unit completion, wait a few secs and then do a nice shutdown and poweroff. No real need to hibernate.

If you want to make it into a nice GUI thingy and can write C++ then the BOINC RPC interface is open source C++ and uses classes. Maybe somebody already has such a script or GUI thingy. Perhaps a new and appropriately named thread will connect you with that somebody or encourage somebody to write it.

Cool, I'll look into that. I'm reasonably comfortable with C++ so I might look at the sources and see if I could add a "Suspend after next checkpoint" button, and get the computer to play a sound or something.