SG_START

NAME

sg_start - starts (spins-up) or stops (spins down) SCSI devices

SYNOPSIS

sg_start [-d] [-imm=0|1] [-loej] [-pc=<n>] [-s] [-V] [0|1] <sg_device>

DESCRIPTION

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.

-d: outputs some extra debug information associated with executing this command
-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.
-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). Obviously only makes sense with removable media.
-pc=<n>: set the 'power conditions' value (in hex); 0 to f (inclusive) are valid. When '-pc=0' then the start value (i.e. 0 or 1) and '-loej' are active. See recent SBC-2 or SAS drafts at www.t10.org for meaning.
-s: send the SYNCHRONIZE CACHE SCSI command to the device prior to sending the START STOP UNIT command.
-V: print out version string then exit.
0: stop (spin-down) given device. Active when '-pc=0' or is not given.
1: start (spin-up) given device. Active when '-pc=0' or is not given.

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.

AUTHOR

Written by K. Garloff and D. Gilbert

REPORTING BUGS

Report bugs to <dgilbert@interlog.com>.

COPYRIGHT