term% cat index.txt DISKSIM(8) System Manager's Manual DISKSIM(8)
NAME
disksim - disk simulator
SYNOPSIS
aux/disksim [ -r ] [ -f file ] [ -s srvname ] [ -m mtpt ] [ diskname ]
DESCRIPTION
Disksim presents an in-memory disk in the manner of the sd(3) device on
mtpt/diskname (default /dev/sdXX). The disk is initialized to zeros;
non-zeroed blocks written to the disk are kept in memory.
When setting disk geometry with the geometry control message, the argu‐
ments are sectors, sector size, cylinders, heads, and sectors per
track. The last three may be zero for LBA disk simulations, but must
be present.
The -f option causes disksim to use file as the initial contents of the
disk rather than a zeroed image. Changes made to the disk are written
back to file unless the -r option is given.
The -s option causes disksim to post its 9P service at /srv/service.
EXAMPLES
Disksim can be used to test programs such as fdisk and prep(8) that ex‐
pect sd(3) disks:
aux/disksim
echo geometry 40000 512 0 0 0 >/dev/sdXX/ctl # 20MB
disk/mbr /dev/sdXX/data
disk/fdisk -baw /dev/sdXX/data
disk/prep /dev/sdXX/plan9
Disksim is useful for creating very large but mostly zeroed files for
testing other programs. Test tar(1)'s handling of large files:
for(i in sdXX sdYY sdZZ) aux/disksim $i
echo geometry 40000000 512 0 0 0 >/dev/sdXX/ctl # 20GB
echo geometry 10000000 512 0 0 0 >/dev/sdYY/ctl # 5GB
echo geometry 20000000 512 0 0 0 >/dev/sdZZ/ctl # 10GB
tar cf /dev/sdXX/data /dev/sdYY/data /dev/sdZZ/data
tar tvf /dev/sdXX/data
SOURCE
/sys/src/cmd/aux/disksim.c
SEE ALSO
sd(3), prep(8)
DISKSIM(8)