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
              prevent"  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 © 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)