Interdata_v6/usr/doc/man/man4/mem.4

Find at most related files.
including files from this version of Unix. 
.th MEM IV
.sh NAME
mem, kmem, null - core memory
.sh DESCRIPTION
.it mem
is a special file which is an image of the core memory of the computer.
It may be used, for example, to examine and even to patch the system
using
.it ddt.

The file
.it kmem
is the same as
.it mem
except that kernel-mode virtual memory rather than physical memory
is accessed.
In particular, the area beginning at x'E0000' is the system's data area
for the current process, including the kernel-mode stack.

The file
.it null
returns end-of-file on
.it read
and ignores
.it write.
.sh FILES
/dev/mem, /dev/kmem, /dev/null