SG_PREVENT(8)							     SG3_UTILS							     SG_PREVENT(8)

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 (C) 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  PUR-
       POSE.

SEE ALSO

       sg_start(sg3_utils), sg_persist(sg3_utils)

sg3_utils-1.23							   January 2007 						     SG_PREVENT(8)