What are these mysterious core.xxx files doing in my site's root? I have never seen this before in my 2 years of building site's in Drupal. I just opened up one of my sites folder structure and found a large number of core.xxx files that I don't know what they do (and they are huge files, over 8GB worth). I found a couple of threads on this but no real answer. Any thoughts?

http://drupal.org/node/360867
http://drupal.org/node/115654

core.1688
core.2343
core.8485
core.3039
core.21233
core.23234
They are core dump files; they are files created when a program has terminated abnormally (crashed).