NAME

       sg_start - send SCSI START STOP UNIT command: 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 conjunction with --start (i.e. load medium then spin up). Alternatively --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 preferred 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.

       -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 appropriate 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  limits 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 --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 (decimal 11) for FORCE_STANDBY_0 (SBC). See recent SBC-3, MMC-5 and SAS
              drafts at www.t10.org for more information.

       -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.

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 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 command (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 example "sg_start 0 /dev/sda" will
       work in the 2.6 series kernels.

       In the Linux 2.6 series, especially with ATA disks, using this utility to stop (spin down) a disk may not
       be sufficient 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. Otherwise 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 setting the SG3_UTILS_OLD_OPTS
       environment variable or using '--old' (or '-O) as the first option.

       Note that the action of --loej is slightly different in the older interface:  when  neither  --start  nor
       --stop  (nor  proxies  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  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 limits 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 © 2002-2012 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)