netbsd man page for drum

DRUM(4) 						   BSD Kernel Interfaces Manual 						   DRUM(4)

NAME
     drum -- paging device

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.

FILES
     /dev/drum

HISTORY
     The drum special file appeared in 3.0BSD.

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.

BSD
								   June 5, 1993 							       BSD