# sg_prevent - send SCSI PREVENT ALLOW MEDIUM REMOVAL command - man(8) - [phpMan]

[_SG_PREVENT_(8)](https://www.chedong.com/phpMan.php/man/SGPREVENT/8/markdown)                                 SG3_UTILS                                [_SG_PREVENT_(8)](https://www.chedong.com/phpMan.php/man/SGPREVENT/8/markdown)

## 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
              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)](https://www.chedong.com/phpMan.php/man/sg3utils/8/markdown)  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)](https://www.chedong.com/phpMan.php/man/SGPREVENT/8/markdown)