NAME
mem,
kmem
- main memory
DESCRIPTION
The file
/dev/mem
is an interface to the physical memory of the
computer.
Byte offsets in this file are interpreted as physical memory addresses.
Reading and writing this file is equivalent to reading and writing
memory itself.
An error will be returned if an attempt is made to reference
an offset outside of
/dev/mem.
Kernel virtual memory is accessed via the file
/dev/kmem
in the same manner as
/dev/mem.
Only kernel virtual addresses that are currently mapped to memory are allowed.
HP300
On the
HP300,
the last byte of physical memory is always
0xFFFFFFFF
.
Therefore, on an
HP300
with
8MB of memory, physical memory would start
at
0xFF800000
.
On the
HP300,
kernel virtual memory runs from
0
to about
0x2400000
.
FILES
/dev/mem
-
/dev/kmem
-
HISTORY
The files
mem
and
kmem
appeared in
Version 6 AT&T UNIX
.