SG_PREVENT(8) SG3_UTILS SG_PREVENT(8)
NAME
sg_prevent - send 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 pre-
vent" state can be cleared by the owner allowing persistent removal (code 2) or a
power cycle (or anything that resets the device (LU)) 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 (C) 2004-2012 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)
sg3_utils-1.35 November 2012 SG_PREVENT(8)
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