1. A core file is created when a program terminates unexpectedly, due to a bug, or a violation of the operating systems or hardwares protection mechanisms. The operating system kills the program and creates a core file that programmers can use to figure out what went wrong. It contains a detailed description of the state that the program was in when it died. If would like to determine what program a core file came from, use the file command, like this: $ file core That will tell you the name of the program that produced the core dump. You may want to write the maintainer(s) of the program, telling them that their program dumped core. To Enable or Disable Core Dumps you must use the ulimit command in bash, the limit command in tcsh, or the rlimit command in ksh. See the appropriate manual page for details. This setting affects all programs run from the shell (directly or indirectly), not the whole system. If you wish to enable or disable core dumping for all processes by default, you can change the default setting in /usr/include/linux/sched.h. Refer to definition of INIT_TASK, and look also in /usr/include/linux/resource.h. PAM support optimizes the system's environment, including the amount of memory a user is allowed. In some distributions this parameter is configurable in the /etc/security/limits.conf file. From Linux Administrator's Security Guide.

2. n. Main storage or RAM. Dates from the days of ferrite-core memory; now archaic as techspeak most places outside IBM, but also still used in the Unix community and by old-time hackers or those who would sound like them. Some derived idioms are quite current; `in core', for example, means `in memory' (as opposed to `on disk'), and both core dump and the `core image' or `core file' produced by one are terms in favor. Some varieties of Commonwealth hackish prefer store. From Jargon Dictionary