thanks for all your help, I'm still looking, though, it may be tough. At the beginning of the day, I had 80 mb free (the whole disk is 720 mb). The reason that I think the culprit is alsaconf, is that I used the option to scan for every ISA sound driver at every port and irq possible ('cause I had no idea what/where the soundcard was--- note to self: the easy way to do this is with google, found it in about 10 seconds

) and it printed about a zillion messages, and there was disk activity (I stupidly left it unnattended for some time). It might help to know where alsaconf would put the files, or if there is an error log somewhere that it filled up.
to clarify my last question, is there a way to say start a program (say "A"), and then start another program, "B" in another console, with the following behaviour:
Whenever "A" acceses or writes a file (say "F"), "B" prints "Process A accessed file F at 10:59:36 PM" or something of the sort.
update:
I found it! it was in /var/log/ksymoops/
the files were called 20051026170***.(modules or ksyms)
I deleted the whole directory, hopefully my system will survive a reboot!