mem.4

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)mem.4	8.1	9/11/90
.\" SCCSID: @(#)mem.4	8.1	9/11/90
.TH mem 4
.SH Name
mem \- physical main memory image
.SH Description
.NXR "physical main memory image"
.NXR "mem memory file"
The
.PN mem
is a character special file that is an image of the physical main memory
of the computer.
It can be used, for example, to examine
(and even to patch) the running system.
.PP
Byte addresses in
.PN mem
are interpreted as physical memory addresses.
References to nonexistent locations cause errors to be returned.
.PP
Examining and patching device registers is likely
to lead to unexpected results when read-only or write-only
bits are present.
.SH Restrictions
The
.PN mem
memory file is accessed one byte
at a time. This may be inappropriate for some
device registers.
.SH Files
.PN /dev/mem
.SH See Also
MAKEDEV(8)