From Joe Newby on Thu, 01 Apr 1999
Dear Answer Guy:
Love your column, it has given me a lot of information. I've been using
Linux for a while, and I have set up two Linux machines at work for
shared Internet access plus I run Linux exclusively at home, so I'm
somewhere between "newbie" and "guru". I have a question, maybe it's a
stupid one, but it's bugging me anyway.
Periodically, I see files named core appearing here and there throughout my filesystems. One just showed up in /etc/X11 directory. They range in size from 400K to nearly 2MB in size. Looking at them with Midnight Commander reminds me of reading the old DOS .EXE files, as they all seem to start with "ELF".
What are these things, and can they be safely removed? I should point out here that I do experiment with different window managers and sometimes X windows has crashed intermittently. Are these a result of those crashes?
Thanks for your input - I look forward to hearing from you. Joe
A "core" file is a snapshot of a process' memory state just prior to its abnormal termination by the system. It's an image of the program's "core" which is an old term for RAM dating back to a time when computers actually used little ferrite "donuts" suspended in a wire mesh for their memory and storage. These can be used by programmers for post-mortem analysis, clues as to what caused the failure.
core files can be generated any time one of your programs crash for just about any reason. Most of us mortals just delete the things.