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 message,
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 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 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
SEE
sd(3),
prep(8)