V4/man/man5/core.5

.th CORE V 9/10/73
.sh NAME
core \*- format of core image file
.sh DESCRIPTION
UNIX
writes out a core image of a terminated
process when any of various errors occur.
See
.it "signal (II)"
for the list of reasons;
the most common are memory violations, illegal
instructions, bus errors, and user-generated
quit signals.
The core image is called ``core'' and is written in the process's
working directory (provided it can be; normal
access controls apply).
.s3
The first 512 bytes of the core image
are a copy of the system's per-user
data for the process, including the registers
as they were at the time of the fault.
The
remainder represents the actual contents of
the user's core area when the core image
was written.
At the moment, if the text segment
is write-protected and shared,
it is not dumped; otherwise the entire
address space is dumped.
.s3
The actual format of the information in the first 512 bytes is complicated.
A guru will have to be consulted
if enlightenment is required.
In general the debugger
.it "db (I)"
should
be used to deal with core images.
.sh "SEE ALSO"
db(I), signal(II)