That it, I have solve the problem !

BOINC read et write a lot of data in run time. On my usb disk BOINC have a size of 13 MB but my problem is that my usb disk is too slow. I thought that the read /write were done every 30 secondes or 60 secondes. But in fact NO. The agent read data all the time. So, the solution is to move the files on the computer disk , to execute it when I am on my computer and to remove it on my usb disk when I want to leave my computer.

In fact when the agent is moved on the computer disk the agent is always at 100%. So, the problem come from the usb disk whish is too slow on read /write but it was not due to the agent.

Thanks to the community advisor for advice.

Enjoy =)

Update: I tried FILEMON and was quite surprised by the file activity from BOINC. It is almost constantly reading and updating one of it's STATE files (client_state_next.xml, then renamed to client_state.xml) every few seconds. Since this file can be "large" by USB key standards (mine is over 100Kb), this constant access and rewriting will cause definite issues on slower devices.

This is a major difference between UD and BOINC. UD is very memory bound, with very little HD interaction except for checkpoints. Don't you think that the number of re-writes of the state files is excessive? I can see keeping things in memory for a few minutes, and writing periodically, but not this constant in/out traffic.

Now, even if BOINC didn't read/write so much, I would still not install it on a key.

I was able to sucessfully run BOINC on a USB key, but gave it up because I was getting what I considered too many FAAH jobs which returned errors(about 25%) after an apparent successful completion. I was attempting to utilize a machine which had no internet connection. I think the speed of the machine the jobs were crunched on varied so greatly from the speed of the machine which did the downloading and uploading that it confused BOINC. Some of the credits also appeared to turn into outliers, being wildly out of place compared with the others. I never experienced any problems while the jobs were running, but did learn it probably was not the best idea I ever tried.

Cheers

Sgt.Joe

Minnesota Crunchers