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man pages section 8: System Administration Commands

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Updated: Thursday, June 13, 2019
 
 

sg_start (8)

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(8)                        SG3_UTILS                       SG_START(8)



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 addi-
       tional 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 sec-
       tion 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  (pre-
              vented), 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 cho-
              sen,  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  condi-
              tion 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 val-
              ues 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  nui-
              sance  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(7) for descriptions of the following attributes:


       +---------------+--------------------------+
       |ATTRIBUTE TYPE |     ATTRIBUTE VALUE      |
       +---------------+--------------------------+
       |Availability   | system/storage/sg3_utils |
       +---------------+--------------------------+
       |Stability      | Pass-through 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 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 con-
       dition 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 PRE-
       VENT 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 immedi-
              ately after the DEVICE  has  received  the  command.  When  this
              option is 0 (the default) then the utility returns once the com-
              mand 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 per-
              formed. 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 (inclu-
              sive) 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 exe-
              cuting 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) 2002-2012 Kurt Garloff, Douglas Gilbert
       This  software is distributed under the GPL version 2. There is NO war-
       ranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR  PUR-
       POSE.

SEE ALSO
       sg_prevent(sg3_utils),    sg_requests(sg3_utils),    sg_turs(sg3_utils)
       sdparm(sdparm)


       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source was downloaded from  http://sg.danny.cz/sg/p/sg3_utils-1.42.tgz

       Further information about this software can be found on the open source
       community website at http://sg.danny.cz/sg/sg3_utils.html.



sg3_utils-1.35                   November 2012                     SG_START(8)