[NBLUG/talk] Top VIRT memory

[gandalf at sonic.net]

I've got this one application MATLAB that is grabbing about 30gigs of 
VIRT in top. You can watch it build and it generally goes up to 33g or 
so and then backs of to 29g. This is on a 126g system. The RES memory is 
around 600m and the SHR memory is about 100m. Now at first this was 
freaking me out, but today we did some testing and watched the free 
memory as well as buffers and cached. There was little movement. So we 
brought up five instances of the program on different terminals. They 
all showed similar memory usage but free memory just dropped down a gig 
or two.

I've been reading over the descriptions of the top memory and am not 
really sure whats going on, but it looks like it's not harmful. Anybody 
have any ideas or advice?