sg_ident - sends a SCSI REPORT or SET IDENTIFYING INFORMATION command
sg_ident [--ascii] [--clear] [--help] [--itype=IT] [--raw] [--set]
[--verbose] [--version] DEVICE
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
Arguments to long options are mandatory for short options as well.
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.
invokes the Set Identifying Information command with an
information length of zero. This has the effect of clearing the
output the usage message then exit.
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).
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.
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).
increase the level of verbosity, (i.e. debug output).
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.
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
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
The exit status of sg_ident is 0 when it is successful. Otherwise see
the sg3_utils(8) man page.
Written by Douglas Gilbert.
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2005-2009 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
sg_vpd(sg3_utils), sg_rmsn(sg3_utils), sg_get_config(sg3_utils)