DISKSIM(8) 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 mes-
sage, the arguments 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 con-
tents 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 expect 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
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DISKSIM(8) DISKSIM(8)
SEE ALSO
sd(3), prep(8)
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