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SG_PREVENT

NAME

sg_prevent − sends a SCSI PREVENT ALLOW MEDIUM REMOVAL command

SYNOPSIS

sg_prevent [−−allow] [−−help] [−−prevent=PC] [−−verbose] [−−version] DEVICE

DESCRIPTION

Sends a SCSI PREVENT ALLOW MEDIUM REMOVAL command to DEVICE. The default action of this utility is to prevent the removing or ejecting of the medium from a drive. This is done by ignoring the SCSI START STOP UNIT command (see sg_start) and ignoring the eject button on the drive when the user presses it. Drives that hold removable disks, tape cartridges or cd/dvd media typically implement this command. The definition of the "prevent" codes for this command differ between disks and tapes (covered by SBC−3 and SSC−3) and cd/dvd drives (covered by MMC−5). The "prevent codes" described here are from MMC−5.

OPTIONS

Arguments to long options are mandatory for short options as well.
−a
, −−allow

allow medium removal. This is equivalent to setting to ’−−prevent=2’. Cannot be used with −−prevent=PC option (i.e. either use no options (hence prevent removal), this option or −−prevent=PC).

−h, −−help

output the usage message then exit.

−p, −−prevent=PC

where PC is a prevent code value. Defined values are: 0 allows removal, 1 prevents removal (default), 2 allows persistent removal while 3 prevents persistent removal. "Persistent" in this context means that the initiator (port) that successfully uses code 3 blocks other initiators (ports) from allowing removal. A "persistent prevent" state can be cleared by the owner allowing persistent removal (code 2) or a power cycle (or anything that resets the device (lun)) or some special commands (e.g. various service actions of Persistent Reserve Out, see SPC−3).

−v, −−verbose

increase the level of verbosity, (i.e. debug output).

−V, −−version

print the version string and then exit.

EXIT STATUS

The exit status of sg_prevent is 0 when it is successful. Otherwise see the sg3_utils(8) man page.

AUTHORS

Written by Douglas Gilbert.

REPORTING BUGS

Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

Copyright © 2004−2007 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

sg_start(sg3_utils), sg_persist(sg3_utils)

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