How one can tell how much precisely physical memory is free on a given system. I mean if I run: # free -m -t total used free shared buffers cached Mem: 2025 1880 145 0 40 87 -/+ buffers/cache: 1752 273 Swap: 4109 1723 2386 Total: 6135 3603 2532 Looking at the table above I might conclude that 145M is all that's left. but apparently this is not so, because a big chunk of RAM is used for disk cache and can be quickly released/recovered should a portion/all of that memory requested by a malloc. I'm trying to fugure out how much physical memory the system has available at any given time. How can this be calculated, using what numbers? Another question is how a group of users can be limited in terms of memory. I have a system here that's starved by IO and I want ot prevent users jobs allocating big chunks of swap. say if I have a Linux system with 2G of RAM and 4G of swap is it possible to allocate to a _group_ of users 1700M only? -- Warm regards, Michael Green