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. Please use as first option.

       -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 . Since then
       this utility defaults to the newer command line options which can be overridden by using --old (or -O) as
       the first option. See the ENVIRONMENT VARIABLES section for another way to force the use of  these  older
       command line options.

       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, --new
              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.

ENVIRONMENT VARIABLES

       Since sg3_utils version 1.23 the environment variable SG3_UTILS_OLD_OPTS can be given. When it is present
       this  utility will expect the older command line options. So the presence of this environment variable is
       equivalent to using --old (or -O) as the first command line option.

AUTHOR

       Written by K. Garloff and D. Gilbert

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright © 2002-2020 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)

sg3_utils-1.43                                   September 2020                                      SG_START(8)