# sg_prevent(8) - man - 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)