I have an IBM thinkpad t21 with a 20g hard drive and 128mb of ram. I just recently installed Slack 10.1 and after I boot the computer, I run top and it says I only have ~5mb of ram free. Should I have chosen the lowmem kernel when I installed? I thought that was for extremely low mem but I haven't been able to find any real guidelines for when it should be used.

as a side note... I have been doing some development in netbeans and when I am just navigating through the editor, top shows 4-5 procs called java and each says it's using ~70% of my ram, but swap is still fairly free. It gets hard because even just navigating and typing has noticable periodic lags (periodic = 3-5s) which can get kind of annoying when I am doing a good amount of typing. Is my comp just not suited or is there something I can do to help things out? Oh, and I'm running fluxbox as my wm to try to keep those resources low as well. Thanks!

Linux uses a lot of memory for caching stuff. That means, the RAM is always mostly full with cache and when a program needs memory, the cache are freeded.
Run free command and you'll see the amount of memory really being used (it will show cached/non-cached and both).

lowmem kernel is for computers with 4 MB of RAM, 128 is a lot

cool thanks. I ran free and now I see that I have closer to 75mb free. Any ideas on what's causing netbeans to run so slowly though? Thanks again.