Is it possible to reserve cpu & ram space for OS only?

[MasterNetra]

With only 1GB of ram, my system at times tends to lock up with software (namely minecraft > : ) ) consuming too much ram and/or the CPUs. So I was wondering if there was some way to limit ram and/or cpu consumption from software so that there is at least enough to force kill without waiting 5-15 min to take into effect. I personally don't think so but I figured it doesn't hurt to ask.

[Cheesehead]

if there was some way to limit ram and/or cpu consumption from software

Of course there is. See man nice or man renice. You can also renice processes from within System Monitor.


DESCRIPTION
Renice alters the scheduling priority of one or more running processes.
The following who parameters are interpreted as process ID's, process
group ID's, or user names. Renice'ing a process group causes all pro‐
cesses in the process group to have their scheduling priority altered.
Renice'ing a user causes all processes owned by the user to have their
scheduling priority altered. By default, the processes to be affected
are specified by their process ID's.