| .TH SG_START "8" "April 2005" "sg3_utils-1.14" SG3_UTILS |
| .SH NAME |
| sg_start \- starts (spins-up) or stops (spins down) SCSI devices |
| .SH SYNOPSIS |
| .B sg_start |
| [\fI-imm=0|1\fR] [\fI-loej\fR] [\fI-pc=<n>\fR] |
| [\fI-v\fR] [\fI-V\fR] \fI0|1\fR \fI<scsi_device>\fR |
| .SH DESCRIPTION |
| .\" Add any additional description here |
| .PP |
| sg_start sends a START STOP UNIT SCSI command to the given device with |
| the selected options. The most used options are "0" to spin down a disk |
| and "1" to spin up a disk. Using "sg_start 1 /dev/sg0" on a disk that |
| is already spinning is harmless. There is also finer grain control |
| with "power conditions": active, idle and standby. In some contexts |
| the "stop" state can be considered an additional power condition. |
| .PP |
| Devices that contain removable media such as cd/dvds can use the '-loej' |
| flag to load the media when used in conjunction with "1" (i.e. load media |
| then spin up). Alternatively '-loej' may be used to eject the media when |
| used alone or when used in conjunction with "0" (i.e. spin down then eject |
| media). |
| .TP |
| 0 |
| stop (spin-down) given device. Active when '-pc=0' or is not given. |
| .TP |
| 1 |
| start (spin-up) given device. Active when '-pc=0' or is not given. |
| .TP |
| -imm=0|1 |
| when the immediate bit is 1 (default) then this command (and hence this |
| utility) return immediately after the device has received the command. |
| When this switch is 0 then the command returns when the action it |
| requests has been completed. |
| .TP |
| -loej |
| load the media when the unit is started or eject it when the unit is |
| stopped. 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 (neither "0" nor "1") and this option is given then a stop and |
| eject action is assumed. |
| .TP |
| -pc=<n> |
| set the 'power conditions' value (in hex); 0 to f (inclusive) are valid. |
| Default value is 0. |
| When '-pc=0' then the start value (i.e. 0 or 1) and '-loej' are active. |
| Some common values are 1 for the active power condition; 2 for the idle |
| power condition; 3 for the standby power condition, 7 for LU_CONTROL, |
| a (hex == decimal 10) for FORCE_IDLE_0 and b (hex) for FORCE_STANDBY_0. |
| See recent SBC-2 or SAS drafts at www.t10.org for more information. |
| .TP |
| -v |
| verbose: outputs SCSI command in hex to console before with executing |
| it. '-vv' and '-vvv' are also accepted yielding greater verbosity. |
| .TP |
| -V |
| print out version string then exit. |
| .PP |
| 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 sg_modes utility can be used to view the |
| power condition mode page and the sginfo utility can view and change it. |
| If a device is in either idle or standby power condition state then |
| a REQUEST SENSE command (se the sg_requests utility) should yield |
| a sense key of "no sense" and an additional sense code of "Low |
| power condition on". |
| .PP |
| Ejection of removable media (e.g. 'sg_start 0 -loej /dev/hdd' where |
| the device is an ATAPI cd/dvd drive) may be prevented by a prior |
| PREVENT ALLOW MEDIUM REMOVAL SCSI command (see sg_prevent). In this |
| case this utility should fail with an error generated by the device: |
| illegal request / medium removal prevented. |
| .PP |
| In the 2.4 series of Linux kernels the given device must be |
| a SCSI generic (sg) device. In the 2.6 series block devices (e.g. disks |
| and SCSI DVDs) can also be specified. For example "sg_start 0 /dev/sda" |
| will work in the 2.6 series kernels. |
| .SH NOTE |
| Earlier versions 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. |
| .SH AUTHOR |
| Written by K. Garloff and D. Gilbert |
| .SH "REPORTING BUGS" |
| Report bugs to <dgilbert at interlog dot com>. |
| .SH COPYRIGHT |
| Copyright \(co 2002-2005 Kurt Garloff, Douglas Gilbert |
| .br |
| This software is distributed under the GPL version 2. There is NO |
| warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| .SH "SEE ALSO" |
| .B sg_prevent(sg3_utils), sg_requests(sg3_utils), sg_modes(sg3_utils), |
| .B sginfo(sg3_utils) |
