[unix-history] / usr / man / man4 / mem.4

.TH MEM 4 
.SH NAME
mem, kmem  \-  core memory
.SH DESCRIPTION
.I Mem
is a special file that is an image of the core memory
of the computer.
It may be used, for example, to examine,
and even to patch the system.
.I Kmem
is the same as 
.I mem
except that kernel virtual memory
rather than physical memory is accessed.
.PP
Byte addresses
are interpreted as memory addresses.
References to non-existent locations return errors.
.PP
Examining and patching device registers is likely
to lead to unexpected results when read-only or write-only
bits are present.
.PP
On PDP11's, the I/O page
begins at location 0160000 of
.I kmem
and per-process data for the current process
begins at 0140000.
.SH FILES
/dev/mem,
/dev/kmem
.SH BUGS
On PDP11's, memory files are accessed one byte
at a time, an inapproriate method for some
device registers.
Commit	Line	Data
70b96c2d DR	1	.TH MEM 4
	2	.SH NAME
	3	mem, kmem \- core memory
	4	.SH DESCRIPTION
	5	.I Mem
	6	is a special file that is an image of the core memory
	7	of the computer.
	8	It may be used, for example, to examine,
	9	and even to patch the system.
	10	.I Kmem
	11	is the same as
	12	.I mem
	13	except that kernel virtual memory
	14	rather than physical memory is accessed.
	15	.PP
	16	Byte addresses
	17	are interpreted as memory addresses.
	18	References to non-existent locations return errors.
	19	.PP
	20	Examining and patching device registers is likely
	21	to lead to unexpected results when read-only or write-only
	22	bits are present.
	23	.PP
	24	On PDP11's, the I/O page
	25	begins at location 0160000 of
	26	.I kmem
	27	and per-process data for the current process
	28	begins at 0140000.
	29	.SH FILES
	30	/dev/mem,
	31	/dev/kmem
	32	.SH BUGS
	33	On PDP11's, memory files are accessed one byte
	34	at a time, an inapproriate method for some
	35	device registers.