In many OS's like WindowsNT, for example, a core dump is basically the computer barfing up everything it has in memory (ram) at that moment. WindowsNT, XP and 2000 use core dumps so that an administrator can perhaps recover from a system crash. OS's like Linux and Unix use core dumps as well, but since they are more stable Operating Systems, they rarely dump the core. For many of us home users, a core dump is just a huge waste of hard drive space and they are safe to delete. If you were working on some important document at the time your system "barfed" or crashed, a technically savvy pro could recover (maybe) some of what you might otherwise have lost using the core dump. Additionally, it can help the programmer to determine why the system crashed, or caused a "SEGFAULT".
Answer-- A core dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has terminated abnormally (crashed).[1] In practice, other key pieces of program state are usually dumped at the same time, including the processor registers, which may include the program counter and stack pointer, memory management information, and other processor and operating system flags and information. The name comes from the once-standard core memory technology. Core dumps are often used to diagnose or debug errors in computer programs.
On many operating systems, a fatal error in a program automatically triggers a core dump, and by extension the phrase "to dump core" has come to mean, in many cases, any fatal error, regardless of whether a record of the program memory results.
