1SG_START(8)                        SG3_UTILS                       SG_START(8)
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3
4

NAME

6       sg_start  -  send  SCSI  START  STOP UNIT command: start, stop, load or
7       eject medium
8

SYNOPSIS

10       sg_start  [0]  [1]  [--eject]  [--help]  [--fl=FL]  [--immed]  [--load]
11       [--loej]  [--mod=PC_MOD]  [--noflush]  [--pc=PC] [--readonly] [--start]
12       [--stop] [--verbose] [--version] DEVICE
13
14       sg_start  [--eject]  [--fl=FL]  [-i]  [--imm=0|1]   [--load]   [--loej]
15       [--mod=PC_MOD]  [--noflush] [--pc=PC] [-r] [--start] [--stop] [-v] [-V]
16       [0|1] DEVICE
17

DESCRIPTION

19       sg_start sends a SCSI START STOP UNIT command to the  DEVICE  with  the
20       selected  options. The most used options are --stop to spin down a disk
21       and --start to spin up a disk. Using --start on a disk that is  already
22       spinning  is  harmless.  There  is also finer grain control with "power
23       condition": active, idle or standby. This is set with the  --pc=PC  op‐
24       tion. In some contexts the "stop" state can be considered an additional
25       power condition.
26
27       Devices that contain removable media such as cd/dvds can use the --loej
28       option  to  load the medium when used in conjunction with --start (i.e.
29       load medium then spin up). Alternatively --loej may be  used  to  eject
30       the  medium  when  used in conjunction with --stop (i.e. spin down then
31       eject medium). More simply, the loading  or  ejecting  of  a  removable
32       medium can be requested with the --load or --eject' option.
33
34       If  no  option  or  argument is given then a --start is assumed; as the
35       utility's name suggests.
36
37       This utility supports two command line syntaxes, the preferred  one  is
38       shown first in the synopsis and explained in this section. A later sec‐
39       tion on the old command line syntax outlines the second  group  of  op‐
40       tions.
41

OPTIONS

43       Arguments to long options are mandatory for short options as well.
44
45       0      same action as --stop.
46
47       1      same action as --start.
48
49       -e, --eject
50              stop  the  medium  and eject it from the drive. Only appropriate
51              for a device with  removable  medium.  Might  be  ignored  (pre‐
52              vented), see below.
53
54       -h, --help
55              print out the usage message then exit.
56
57       -f, --fl=FL
58              sets  the format layer number for the disc to "jump" to (defined
59              in MMC-5).  Values of FL can be 0 to 3. When this option is cho‐
60              sen,  the FL, LoEj and Start bits are set in the cdb as required
61              by MMC-5; thus the user does not need to set the --start  and/or
62              --load options.
63
64       -i, --immed
65              sets  the IMM bit on the START STOP UNIT command so this utility
66              will return immediately and not wait for the media  to  complete
67              the  requested action. The default is to wait until the media to
68              complete the requested action before returning.
69
70       -l, --load
71              load the medium in the drive and start it. Only appropriate  for
72              a removable medium.
73
74       -L, --loej
75              sets the LOEJ bit on the START STOP UNIT command. This loads the
76              media when the unit is started or eject  it  when  the  unit  is
77              stopped (i.e.  works in conjunction with START bit in cdb). This
78              option is ignored if 'pc > 0'.  Default is off (i.e.  don't  at‐
79              tempt  to  load  or eject media). If a start/start indication is
80              not given (i.e. neither --start nor --stop) and this  option  is
81              given then a load and start action is assumed.
82
83       -m, --mod=PC_MOD
84              where  PC_MOD  is  the 'power condition modifier' value. 0 to 15
85              (inclusive) are valid and 0 is the default. This  'power  condi‐
86              tion modifier' field in the cdb was added after sbc3r13.
87
88       -n, --noflush
89              do  not  perform  a  flush to media (e.g. like SYNCHRONIZE CACHE
90              does) before a variant of this utility that limits access to the
91              media.  Using  the --stop option is an example of something that
92              limits access to the media. This 'noflush' field in the cdb  was
93              added after sbc3r13.
94
95       -O, --old
96              Switch to older style options. Please use as first option.
97
98       -p, --pc=PC
99              where  PC  is  the 'power conditions' value. 0 to 15 (inclusive)
100              are valid.  Default value is  0.  When  '--pc=0'  then  --eject,
101              --load,  --loej, --start and --stop are active. Some common val‐
102              ues are 1 for the "active" power condition (SBC); 2 for the idle
103              power  condition; 3 for the standby power condition; 5 for sleep
104              power condition (MMC); 7 for LU_CONTROL (SBC), 0xa (decimal  10)
105              for  FORCE_IDLE_0 (SBC) and 0xb (decimal 11) for FORCE_STANDBY_0
106              (SBC). See recent SBC-3, MMC-5 and SAS drafts at www.t10.org for
107              more information.
108
109       -r, --readonly
110              open  the  DEVICE  in read-only mode. Maybe required in Linux to
111              stop a nuisance spin-up if the DEVICE is an ATA disk.  The  nui‐
112              sance  spin-up may occur at the end of this command negating the
113              effect of the --stop option.
114
115       -s, --start
116              start (spin-up) the DEVICE. This sets the START bit in the  cdb.
117              Using  this  option on an already started device is harmless. In
118              the absence of other options, this option defaults (i.e. set the
119              START cdb bit).
120
121       -S, --stop
122              stop  (spin-down)  the  DEVICE. This clears the START bit in the
123              cdb.
124
125       -v, --verbose
126              increase the level of verbosity. Can be used multiple times.
127
128       -V, --version
129              print out version string then exit.
130

NOTES

132       To avoid confusion, only one of  0,  1  --eject,  --load,  --start  and
133       --stop should be given.
134
135       There  is  an  associated  "power  condition" mode page (0x1a) in which
136       timer values can be set for transitioning to  either  idle  or  standby
137       state  after  a period of inactivity. The sdparm utility can be used to
138       view the power condition mode page and if required change it. If a  DE‐
139       VICE  is in either idle or standby power condition state then a REQUEST
140       SENSE command (see the sg_requests utility) should yield a sense key of
141       "no  sense" and an additional sense code of "Low power condition on" on
142       recent SCSI devices.
143
144       Ejection of removable media (e.g. 'sg_start --eject /dev/hdd' where the
145       DEVICE  is an ATAPI cd/dvd drive) may be prevented by a prior SCSI PRE‐
146       VENT ALLOW MEDIUM REMOVAL command (see sg_prevent). In this  case  this
147       utility  should fail with an error generated by the device: illegal re‐
148       quest / medium removal prevented. This can be overridden using  sg_pre‐
149       vent or, for example, 'sdparm --command=unlock /dev/hdd'.
150
151       The  SCSI TEST UNIT READY command can be used to find out whether a DE‐
152       VICE is ready to transfer data. If rotating media is stopped  or  still
153       coming  up to speed, then the TEST UNIT READY command will yield a "not
154       ready" sense key and an more informative additional sense code. See the
155       sg_turs utility.
156
157       In  the  2.4  series of Linux kernels the DEVICE must be a SCSI generic
158       (sg) device. In the 2.6 series block devices (e.g. SCSI disks  and  DVD
159       drives)  can  also be specified. For example "sg_start 0 /dev/sda" will
160       work in the 2.6 series kernels.
161
162       In the Linux 2.6 series, especially with ATA disks, using this  utility
163       to  stop  (spin down) a disk may not be sufficient and other mechanisms
164       will start the disk again some time later. The user might  additionally
165       mark  the  disk  as  "offline"  with 'echo offline > /sys/block/sda/de‐
166       vice/state' where sda is the block name of the  disk.  To  restart  the
167       disk  "offline"  can  be  replaced  with  "running". Note that once the
168       'state' is set to offline, no SCSI commands can be sent to  the  device
169       until  it  is  set  back  to  running.  Also  stopping  a  disk  via  a
170       pass-through interface (e.g. /dev/sg1 or /dev/bsg/1:0:0:0)  may  reduce
171       unwanted  side  effects  (such as restarting it again when this utility
172       completes).
173

EXIT STATUS

175       The exit status of sg_start is 0 when it is successful.  Otherwise  see
176       the sg3_utils(8) man page.
177

OLDER COMMAND LINE OPTIONS

179       The  options  in  this  section  were  the only ones available prior to
180       sg3_utils version 1.23 . Since then this utility defaults to the  newer
181       command  line options which can be overridden by using --old (or -O) as
182       the first option. See the ENVIRONMENT VARIABLES section for another way
183       to force the use of these older command line options.
184
185       Note  that  the action of --loej is slightly different in the older in‐
186       terface: when neither --start nor --stop (nor  proxies  for  them)  are
187       given,  --loej  performs  an eject operation. In the same situation the
188       newer interface will perform a load operation.
189
190       Earlier versions of sg_start had a '-s' option to perform a SYNCHRONIZE
191       CACHE  command before the START STOP UNIT command was issued. According
192       to recent SBC-2 drafts this is done implicitly if required.  Hence  the
193       '-s' option has been dropped.
194
195       All  options, other than '-v' and '-V', can be given with a single "-".
196       For example: "sg_start -stop /dev/sda" and "sg_start  --stop  /dev/sda"
197       are equivalent. The single "-" form is for backward compatibility.
198
199       0      stop (spin-down) DEVICE.
200
201       1      start (spin-up) DEVICE.
202
203       --eject
204              stop the medium and eject it from the drive.
205
206       --fl=FL
207              sets  the format layer number for the disc to "jump" to (defined
208              in MMC-5).
209
210       -i     sets the IMM bit on the START STOP UNIT command so this  utility
211              will return immediately and not wait for the media to spin down.
212              Same effect as '--imm=1'. The default action (without  this  op‐
213              tion  or  a  '--imm=1'  option) is to wait until the media spins
214              down before returning.
215
216       --imm=0|1
217              when the immediate bit is 1 then this  utility  returns  immedi‐
218              ately  after  the DEVICE has received the command. When this op‐
219              tion is 0 (the default) then the utility returns once  the  com‐
220              mand has completed its action (i.e. it waits until the device is
221              started or stopped).
222
223       --load load the medium in the drive and start it.
224
225       --loej sets the LOEJ bit in the START STOP UNIT cdb. When a "start" op‐
226              eration is indicated, then a load and start is performed. When a
227              "stop" operation is indicated, then a stop  and  eject  is  per‐
228              formed.  When neither a "start" or "stop" operation is indicated
229              does a stop and eject. [Note that the last action  differs  from
230              the  new  interface in which the option of this name defaults to
231              load and start.]
232
233       -N, --new
234              Switch to the newer style options.
235
236       --mod=PC_MOD
237              where PC_MOD is the 'power condition modifier' value.  0  to  15
238              (inclusive) are valid and 0 is the default. This field was added
239              after sbc3r13.
240
241       --noflush
242              do not perform a flush to media  (e.g.  like  SYNCHRONIZE  CACHE
243              does) before a variant of this utility that limits access to the
244              media. Using the --stop option is an example of  something  that
245              limits access to the media. This field was added after sbc3r13.
246
247       --pc=PC
248              where PC is the 'power condition' value (in hex). 0 to f (inclu‐
249              sive) are valid. Default value is 0.
250
251       -r     see the --readonly option above. May be useful for ATA disks.
252
253       --start
254              start (spin-up) DEVICE.
255
256       --stop stop (spin-down) DEVICE. Same meaning as "0" argument.
257
258       -v     verbose: outputs SCSI command in hex to console before with exe‐
259              cuting  it.  '-vv' and '-vvv' are also accepted yielding greater
260              verbosity.
261
262       -V     print out version string then exit.
263

ENVIRONMENT VARIABLES

265       Since    sg3_utils    version    1.23    the    environment    variable
266       SG3_UTILS_OLD_OPTS  can  be given. When it is present this utility will
267       expect the older command line options. So the presence of this environ‐
268       ment variable is equivalent to using --old (or -O) as the first command
269       line option.
270

AUTHOR

272       Written by K. Garloff and D. Gilbert
273

REPORTING BUGS

275       Report bugs to <dgilbert at interlog dot com>.
276
278       Copyright © 2002-2020 Kurt Garloff, Douglas Gilbert
279       This software is distributed under the GPL version 2. There is NO  war‐
280       ranty;  not  even  for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
281       POSE.
282

SEE ALSO

284       sg_prevent(sg3_utils), sg_requests(sg3_utils),  sg_turs(sg3_utils)  sd‐
285       parm(sdparm)
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287
288
289sg3_utils-1.43                  September 2020                     SG_START(8)
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