man > sg_prevent(8)

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  com‐
       mand  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 op‐
              tion 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 re‐
              moval  (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  cy‐
              cle  (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 © 2004-2012 Douglas Gilbert
       This software is distributed under a FreeBSD license. There is NO warranty; not even for MER‐
       CHANTABILITY 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)