Provided by: sg3-utils_1.17-2_i386
sg_start - starts (spins-up) or stops (spins down) SCSI device, load or
sg_start [-eject] [-imm=0|1] [-load] [-loej] [-pc=<n>] [-start] [-stop]
[-v] [-V] [0|1] <scsi_device>
sg_start sends a START STOP UNIT SCSI command to the given device with
the selected options. The most used options are ’-stop’ to spin down a
disk and ’-start’ to spin up a disk. Using ’sg_start -start /dev/sda’
on a disk that is already spinning is harmless. There is also finer
grain control with "power conditions": active, idle and standby. In
some contexts the "stop" state can be considered an additional power
Devices that contain removable media such as cd/dvds can use the
’-loej’ flag to load the medium when used in conjunction with ’-start’
(i.e. load medium then spin up). Alternatively ’-loej’ may be used to
eject the medium when used alone or when used in conjunction with
’-stop’ (i.e. spin down then eject medium). More simply the loading and
ejecting of a removable medium can be requested with the ’-load’ and
If no option or argument is given that implies some action, a ’-start’
0 stop (spin-down) given device. Active when ’-pc=" is not given
1 start (spin-up) given device. Active when ’-pc=" is not given
or ’-pc=0’. Harmless if device has already started (or is in the
process of starting).
-eject stop the medium and eject it from the drive. Only appropriate
for a removable medium.
when the immediate bit is 1 then this utility returns
immediately after the device has received the command. When this
option is 0 (the default) then the utility returns once the
command has completed its action (i.e. it waits until the device
is started or stopped).
-load load the medium in the drive and start it. Only appropriate for
a removable medium.
-loej load the media when the unit is started or eject it when the
unit is stopped. This option is ignored if ’pc > 0’. Default is
off (i.e. don’t attempt to load or eject media). If a
start/start indication is not given (neither "-start" nor
"-stop") and this option is given then a stop and eject action
set the ’power conditions’ value (in hex); 0 to f (inclusive)
are valid. Default value is 0. When ’-pc=0’ then ’-start’,
’-stop’ and ’-loej’ are active. Some common values are 1 for
the active power condition (SBC); 2 for the idle power
condition; 3 for the standby power condition; 5 for sleep power
condition (MMC); 7 for LU_CONTROL (SBC), 0xa (decimal 10) for
FORCE_IDLE_0 (SBC) and 0xb (decimal 11) for FORCE_STANDBY_0
(SBC). See recent SBC-2, MMC-4 and SAS drafts at www.t10.org
for more information.
-start start (spin-up) given device. Using this option on an already
started device is harmless. Same meaning as "1" argument.
-stop stop (spin-down) given device. Same meaning as "0" argument.
-v verbose: outputs SCSI command in hex to console before with
executing it. ’-vv’ and ’-vvv’ are also accepted yielding
-V print out version string then exit.
To avoid confusion, only one of "0", "1", "-start" and "-stop" can be
If this utility succeeds then its process exits with a status of 0;
otherwise it exits with a non-zero status.
There is an associated "power condition" mode page (0x1a) in which
timer values can be set for transitioning to either idle or standby
state after a period of inactivity. The sdparm utility can be used to
view the power condition mode page and the sginfo utility can view and
change it. If a device is in either idle or standby power condition
state then a REQUEST SENSE command (see the sg_requests utility) should
yield a sense key of "no sense" and an additional sense code of "Low
power condition on".
Ejection of removable media (e.g. ’sg_start -eject /dev/hdd’ where the
device is an ATAPI cd/dvd drive) may be prevented by a prior PREVENT
ALLOW MEDIUM REMOVAL SCSI command (see sg_prevent). In this case this
utility should fail with an error generated by the device: illegal
request / medium removal prevented.
In the 2.4 series of Linux kernels the given device must be a SCSI
generic (sg) device. In the 2.6 series block devices (e.g. disks and
SCSI DVDs) can also be specified. For example "sg_start 0 /dev/sda"
will work in the 2.6 series kernels.
Earlier versions had a ’-s’ option to perform a SYNCHRONIZE CACHE
command before the START STOP UNIT command was issued. According to
recent SBC-2 drafts this is done implicitly if required. Hence the "-s"
option has been dropped.
Written by K. Garloff and D. Gilbert
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2002-2005 Kurt Garloff, Douglas Gilbert
This software is distributed under the GPL version 2. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
sg_prevent(sg3_utils), sg_requests(sg3_utils), sdparm(sdparm),