sg_start
(1m)
Name
sg_start - send SCSI START STOP UNIT command to start, stop,
load or eject medium
Synopsis
sg_start [0] [1] [--eject] [--help] [--fl=FL] [--immed]
[--load] [--loej] [--mod=PC_MOD] [--noflush] [--pc=PC]
[--readonly] [--start] [--stop] [--verbose] [--version]
DEVICE
sg_start [--eject] [--fl=FL] [-i] [--imm=0|1] [--load]
[--loej] [--mod=PC_MOD] [--noflush] [--pc=PC] [-r] [--start]
[--stop] [-v] [-V] [0|1] DEVICE
Description
SG3_UTILS SG_START(8)
NAME
sg_start - send SCSI START STOP UNIT command to start, stop,
load or eject medium
SYNOPSIS
sg_start [0] [1] [--eject] [--help] [--fl=FL] [--immed]
[--load] [--loej] [--mod=PC_MOD] [--noflush] [--pc=PC]
[--readonly] [--start] [--stop] [--verbose] [--version]
DEVICE
sg_start [--eject] [--fl=FL] [-i] [--imm=0|1] [--load]
[--loej] [--mod=PC_MOD] [--noflush] [--pc=PC] [-r] [--start]
[--stop] [-v] [-V] [0|1] DEVICE
DESCRIPTION
sg_start sends a SCSI START STOP UNIT command to the DEVICE
with the selected options. The most used options are --stop
to spin down a disk and --start to spin up a disk. Using
--start on a disk that is already spinning is harmless.
There is also finer grain control with "power condition":
active, idle or standby. This is set with the --pc=PC
option. In some contexts the "stop" state can be considered
an additional power condition.
Devices that contain removable media such as cd/dvds can use
the --loej option to load the medium when used in conjunc-
tion with --start (i.e. load medium then spin up). Alterna-
tively --loej may be used to eject the medium when used in
conjunction with --stop (i.e. spin down then eject medium).
More simply, the loading or ejecting of a removable medium
can be requested with the --load or --eject' option.
If no option or argument is given then a --start is assumed;
as the utility's name suggests.
This utility supports two command line syntaxes, the pre-
ferred one is shown first in the synopsis and explained in
this section. A later section on the old command line syntax
outlines the second group of options.
OPTIONS
Arguments to long options are mandatory for short options as
well.
0 same action as --stop.
1 same action as --start.
-e, --eject
stop the medium and eject it from the drive. Only
appropriate for a device with removable medium. Might
be ignored (prevented), see below.
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SG3_UTILS SG_START(8)
-h, --help
print out the usage message then exit.
-f, --fl=FL
sets the format layer number for the disc to "jump" to
(defined in MMC-5). Values of FL can be 0 to 3. When
this option is chosen, the FL, LoEj and Start bits are
set in the cdb as required by MMC-5; thus the user does
not need to set the --start and/or --load options.
-i, --immed
sets the IMM bit on the START STOP UNIT command so this
utility will return immediately and not wait for the
media to complete the requested action. The default is
to wait until the media to complete the requested
action before returning.
-l, --load
load the medium in the drive and start it. Only appro-
priate for a removable medium.
-L, --loej
sets the LOEJ bit on the START STOP UNIT command. This
loads the media when the unit is started or eject it
when the unit is stopped (i.e. works in conjunction
with START bit in cdb). 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
(i.e. neither --start nor --stop) and this option is
given then a load and start action is assumed.
-m, --mod=PC_MOD
where PC_MOD is the 'power condition modifier' value. 0
to 15 (inclusive) are valid and 0 is the default. This
'power condition modifier' field in the cdb was added
after sbc3r13.
-n, --noflush
do not perform a flush to media (e.g. like SYNCHRONIZE
CACHE does) before a variant of this utility that lim-
its access to the media. Using the --stop option is an
example of something that limits access to the media.
This 'noflush' field in the cdb was added after
sbc3r13.
-O, --old
switch to older style options.
-p, --pc=PC
where PC is the 'power conditions' value. 0 to 15
(inclusive) are valid. Default value is 0. When
'--pc=0' then --eject, --load, --loej, --start and
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SG3_UTILS SG_START(8)
--stop 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 (deci-
mal 11) for FORCE_STANDBY_0 (SBC). See recent SBC-3,
MMC-5 and SAS drafts at www.t10.org for more informa-
tion.
-r, --readonly
open the DEVICE in read-only mode. Maybe required in
Linux to stop a nuisance spin-up if the DEVICE is an
ATA disk. The nuisance spin-up may occur at the end of
this command negating the effect of the --stop option.
-s, --start
start (spin-up) the DEVICE. This sets the START bit in
the cdb. Using this option on an already started device
is harmless. In the absence of other options, this
option defaults (i.e. set the START cdb bit).
-S, --stop
stop (spin-down) the DEVICE. This clears the START bit
in the cdb.
-v, --verbose
increase the level of verbosity. Can be used multiple
times.
-V, --version
print out version string then exit.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | system/storage/sg3_utils |
+---------------+--------------------------+
|Stability | Uncommitted |
+---------------+--------------------------+
NOTES
To avoid confusion, only one of 0, 1 --eject, --load,
--start and --stop should be given.
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
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SG3_UTILS SG_START(8)
page and if required 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" on recent SCSI devices.
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 SCSI PREVENT ALLOW MEDIUM REMOVAL com-
mand (see sg_prevent). In this case this utility should fail
with an error generated by the device: illegal request /
medium removal prevented. This can be overridden using
sg_prevent or, for example, 'sdparm --command=unlock
/dev/hdd'.
The SCSI TEST UNIT READY command can be used to find out
whether a DEVICE is ready to transfer data. If rotating
media is stopped or still coming up to speed, then the TEST
UNIT READY command will yield a "not ready" sense key and an
more informative additional sense code. See the sg_turs
utility.
In the 2.4 series of Linux kernels the DEVICE must be a SCSI
generic (sg) device. In the 2.6 series block devices (e.g.
SCSI disks and DVD drives) can also be specified. For exam-
ple "sg_start 0 /dev/sda" will work in the 2.6 series ker-
nels.
In the Linux 2.6 series, especially with ATA disks, using
this utility to stop (spin down) a disk may not be suffi-
cient and other mechanisms will start the disk again some
time later. The user might additionally mark the disk as
"offline" with 'echo offline > /sys/block/sda/device/state'
where sda is the block name of the disk. To restart the disk
"offline" can be replaced with "running". Note that once the
'state' is set to offline, no SCSI commands can be sent to
the device until it is set back to running. Also stopping a
disk via a pass-through interface (e.g. /dev/sg1 or
/dev/bsg/1:0:0:0) may reduce unwanted side effects (such as
restarting it again when this utility completes).
EXIT STATUS
The exit status of sg_start is 0 when it is successful. Oth-
erwise see the sg3_utils(8) man page.
OLDER COMMAND LINE OPTIONS
The options in this section were the only ones available
prior to sg3_utils version 1.23 . In sg3_utils version 1.23
and later these older options can be selected by either set-
ting the SG3_UTILS_OLD_OPTS environment variable or using
'--old' (or '-O) as the first option.
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SG3_UTILS SG_START(8)
Note that the action of --loej is slightly different in the
older interface: when neither --start nor --stop (nor prox-
ies for them) are given, --loej performs an eject operation.
In the same situation the newer interface will perform a
load operation.
Earlier versions of sg_start 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.
All options, other than '-v' and '-V', can be given with a
single "-". For example: "sg_start -stop /dev/sda" and
"sg_start --stop /dev/sda" are equivalent. The single "-"
form is for backward compatibility.
0 stop (spin-down) DEVICE.
1 start (spin-up) DEVICE.
--eject
stop the medium and eject it from the drive.
--fl=FL
sets the format layer number for the disc to "jump" to
(defined in MMC-5).
-i sets the IMM bit on the START STOP UNIT command so this
utility will return immediately and not wait for the
media to spin down. Same effect as '--imm=1'. The
default action (without this option or a '--imm=1'
option) is to wait until the media spins down before
returning.
--imm=0|1
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.
--loej
sets the LOEJ bit in the START STOP UNIT cdb. When a
"start" operation is indicated, then a load and start
is performed. When a "stop" operation is indicated,
then a stop and eject is performed. When neither a
"start" or "stop" operation is indicated does a stop
and eject. [Note that the last action differs from the
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SG3_UTILS SG_START(8)
new interface in which the option of this name defaults
to load and start.]
-N switch to the newer style options.
--mod=PC_MOD
where PC_MOD is the 'power condition modifier' value. 0
to 15 (inclusive) are valid and 0 is the default. This
field was added after sbc3r13.
--noflush
do not perform a flush to media (e.g. like SYNCHRONIZE
CACHE does) before a variant of this utility that lim-
its access to the media. Using the --stop option is an
example of something that limits access to the media.
This field was added after sbc3r13.
--pc=PC
where PC is the 'power condition' value (in hex). 0 to
f (inclusive) are valid. Default value is 0.
-r see the --readonly option above. May be useful for ATA
disks.
--start
start (spin-up) DEVICE.
--stop
stop (spin-down) 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 greater verbosity.
-V print out version string then exit.
AUTHOR
Written by K. Garloff and D. Gilbert
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2002-2011 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 PURPOSE.
SEE ALSO
sg_prevent(sg3_utils), sg_requests(sg3_utils),
sg_turs(sg3_utils) sdparm(sdparm)
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SG3_UTILS SG_START(8)
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from
http://sg.danny.cz/sg/p/sg3_utils-1.33.tgz
Further information about this software can be found on the
open source community website at
http://sg.danny.cz/sg/sg3_utils.html.
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