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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  op-
       tion. 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 sec-
       tion on the old command line syntax outlines the	second	group  of  op-
       tions.

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  at-
	      tempt  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. 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 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.

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  DE-
       VICE  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 PRE-
       VENT ALLOW MEDIUM REMOVAL command (see sg_prevent). In this  case  this
       utility	should fail with an error generated by the device: illegal re-
       quest / medium removal prevented. This can be overridden	using  sg_pre-
       vent or,	for example, 'sdparm --command=unlock /dev/hdd'.

       The  SCSI TEST UNIT READY command can be	used to	find out whether a DE-
       VICE 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/de-
       vice/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 in-
       terface:	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  op-
	      tion  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 op-
	      tion 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" op-
	      eration 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, --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 (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.

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 environ-
       ment 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 (C) 2002-2017 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)  sd-
       parm(sdparm)

sg3_utils-1.43			 October 2017			   SG_START(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | EXIT STATUS | OLDER COMMAND LINE OPTIONS | ENVIRONMENT VARIABLES | AUTHOR | REPORTING BUGS | COPYRIGHT | SEE ALSO

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