bionic (8) sg_ident.8.gz

NAME

       sg_ident - send SCSI REPORT/SET IDENTIFYING INFORMATION command

SYNOPSIS

       sg_ident [--ascii] [--clear] [--help] [--itype=IT] [--raw] [--set] [--verbose] [--version] DEVICE

DESCRIPTION

       Send  a  SCSI  REPORT  IDENTIFYING INFORMATION or SET IDENTIFYING INFORMATION command to DEVICE. Prior to
       SPC-4 (revision 7) these commands  were  called  REPORT  DEVICE  IDENTIFIER  and  SET  DEVICE  IDENTIFIER
       respectively.  SCSI  devices  that  support  these  two  commands  allow users to write (set) identifying
       information and report it back at some later time. The information is persistent  (i.e.  stored  on  some
       non-volatile medium within the SCSI device that will survive a power outage).

       Typically  the  space  allocated  for  the  information  is  limited:  SPC-4 (revision 7) states that for
       information type 0, the minimum length is 64 bytes and the maximum is 512 bytes.  For  other  information
       types  (1  to 126 inclusive) the maximum length is 256 bytes. Also information types 1 to 126 (inclusive)
       should contain a null terminated UTF-8 string. The author has seen  older  disks  that  only  support  16
       bytes.

       The default action when no options are given is to invoke the Report Identifying Information command with
       the information type defaulting to zero. Error reports are sent to stderr. By default the information  is
       shown  in  ASCII-HEX  (up  to  16  bytes  per  line)  with an ASCII representation to the right with dots
       replacing non printable characters.

OPTIONS

       Arguments to long options are mandatory for short options as well.

       -A, --ascii
              invokes the Report Identifying Information command and if anything is found interprets it as ASCII
              (or UTF-8 depending on the locale) and prints the information to stdout.

       -C, --clear
              invokes  the  Set Identifying Information command with an information length of zero. This has the
              effect of clearing the existing information.

       -h, --help
              output the usage message then exit.

       -i, --itype=IT
              where IT is the information type. Defaults to zero. The maximum value is 127 which is special  and
              cannot be used with --set or --clear. The information type of 127 (if supported) causes the REPORT
              IDENTIFYING INFORMATION command to respond with a list of available information  types  and  their
              maximum lengths in bytes. The odd numbered information types between 3 and 125 (inclusive) are not
              to be used (as they clash with the SCC-2 standard).

       -r, --raw
              invokes the Report Identifying information command and if anything is found sends the  information
              (which may be binary) to stdout. Nothing else is sent to stdout however error reports, if any, are
              sent to stderr.

       -S, --set
              first reads stdin until an EOF is detected then invokes the Set Identifying Information command to
              set what has been fetched from stdin as the information. The amount of data read must be between 1
              and 512 bytes length (inclusive).

       -v, --verbose
              increase the level of verbosity, (i.e. debug output).

       -V, --version
              print the version string and then exit.

       This utility permits users to write their own identifying information to their SCSI  devices.  There  are
       several  other  types of descriptors (or designators) that the user cannot change. These include the SCSI
       INQUIRY command with its standard vendor and product identification  strings  and  the  product  revision
       level;  plus  the  large  amount  of  information  provided  by the "Device Identification" VPD page (see
       sg_vpd). There is also the READ MEDIA SERIAL NUMBER command (see sg_rmsn). The MMC-4 command set  for  CD
       and  DVDs has a "media serial number" feature (0x109) [and a "logical unit serial number" feature]. These
       can be viewed with the sg_get_config utility.

EXAMPLES

       First, to see if there is an existing information whose format is unknown (for information type  0),  use
       no options:

         # sg_ident /dev/sdb
          00     31 32 33 34 35 36 37 38  39 30          1234567890

       If it is ASCII then it can printed as such:

         # sg_ident --ascii /dev/sdb
         1234567890

       The information can be copied to a file, cleared and then re-asserted with this sequence:

         # sg_ident --raw /dev/sdb > t
         # sg_ident --clear /dev/sdb
         # cat t | sg_ident --set /dev/sdb

EXIT STATUS

       The exit status of sg_ident 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 © 2005-2012 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_vpd(sg3_utils), sg_rmsn(sg3_utils), sg_get_config(sg3_utils)