if you install the boinc like me..."sudo aptitude install boinc-client boinc-manager"the boinc process are running in the background... you can see it.. if you open a terminal and type .. "top "
You should not need to have the Manager open for processing to occur. I am running Ubuntu with BOINC installed and neither Client nor Manager are listed in processes, but the system load is 98-100%. When I periodically check in the manager and online it is completing tasks.
I am still a bit new to the details of Linux, but watching to see if tasks are returned and you are getting credit for them on that computer could be an easy way to check. I am pretty sure things are functioning as they should. Someone correct me if I am wrong.