SG_IDENT(8) SG3_UTILS SG_IDENT(8)
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 DE-
VICE. 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 in-
formation 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 Informa-
tion 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 inter-
prets it as ASCII (or UTF-8 which is locale dependent) 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 Infor-
mation 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 de-
vices. 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 iden-
tification 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 ME-
DIA SERIAL NUMBER command (see sg_rmsn). The MMC-4 command set for CD and DVDs has a "me-
dia 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 (C) 2005-2018 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)
sg3_utils-1.43 August 2018 SG_IDENT(8)
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