[unix-history] / usr / src / share / man / man4 / drum.4

.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)drum.4	8.1 (Berkeley) %G%
.\"
.Dd 
.Dt DRUM 4
.Os BSD 4
.Sh NAME
.Nm drum
.Nd paging device
.Sh DESCRIPTION
This file refers to the paging device in use by the system.
This may actually be a subdevice of one of the disk drivers, but in
a system with paging interleaved across multiple disk drives
it provides an indirect driver for the multiple drives.
.Sh FILES
.Bl -tag -width /dev/drum
.It Pa /dev/drum
.El
.Sh HISTORY
The
.Nm
special file appeared in
.Bx 3.0 .
.Sh BUGS
Reads from the drum are not allowed across the interleaving boundaries.
Since these only occur every .5Mbytes
or so,
and since the system never allocates blocks across the boundary,
this is usually not a problem.
Commit	Line	Data
5ebe7d4b KB	1	.\" Copyright (c) 1980, 1991, 1993
5ebe7d4b KB	2	.\" The Regents of the University of California. All rights reserved.
51eec7de	3	.\"
9903e566	4	.\" %sccs.include.redist.man%
51eec7de	5	.\"
5ebe7d4b	6	.\" @(#)drum.4 8.1 (Berkeley) %G%
9903e566 CL	7	.\"
	8	.Dd
	9	.Dt DRUM 4
	10	.Os BSD 4
	11	.Sh NAME
	12	.Nm drum
	13	.Nd paging device
	14	.Sh DESCRIPTION
51eec7de KM	15	This file refers to the paging device in use by the system.
	16	This may actually be a subdevice of one of the disk drivers, but in
	17	a system with paging interleaved across multiple disk drives
	18	it provides an indirect driver for the multiple drives.
9903e566 CL	19	.Sh FILES
	20	.Bl -tag -width /dev/drum
	21	.It Pa /dev/drum
	22	.El
	23	.Sh HISTORY
	24	The
	25	.Nm
	26	special file appeared in
	27	.Bx 3.0 .
	28	.Sh BUGS
51eec7de	29	Reads from the drum are not allowed across the interleaving boundaries.
9903e566	30	Since these only occur every .5Mbytes
51eec7de KM	31	or so,
	32	and since the system never allocates blocks across the boundary,
	33	this is usually not a problem.