usr/man/man4/drum.4

.TH DRUM 4 5/11/81
.UC 4
.SH NAME
drum \- 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
/dev/drum
.SH BUGS
Reads from the drum are not allowed across the interleaving boundaries.
Since these only occur every
.BR . 5Mbytes
or so,
and since the system never allocates blocks across the boundary,
this is usually not a problem.