sg_vpd - fetch SCSI VPD page and/or decode its response
] [ --ident
] [ --page=PG
] [ --verbose
This utility, when DEVICE
is given, fetches a Vital Product Data (VPD)
page and decodes it or outputs it in ASCII hexadecimal or binary. VPD pages
are fetched with a SCSI INQUIRY command.
Alternatively the --inhex=FN
option can be given. In this case FN
is assumed to be a file name ('-' for stdin) containing ASCII hexadecimal
representing a VPD page response. If the --raw
option is also given
then binary input is assumed (rather than ASCII hexadecimal).
Probably the most important page is the Device Identification VPD page (page
number: 0x83). Since SPC-3, support for this page has been flagged as
mandatory. This page can be fetched by using the --ident
The reference document used for interpreting VPD pages (and the INQUIRY standard
response) is T10/BSR INCITS 502 Revision 08 which is draft SPC-5 revision 08,
25 January 2016). It can be found at http://www.t10.org .
When no options are given, other than a DEVICE
, then the "Supported
VPD pages" (0x0) VPD page is fetched and decoded.
Arguments to long options are mandatory for short options as well. The options
are arranged in alphabetical order based on the long option name.
- -a, --all
- decode all VPD pages. When used with DEVICE the
pages to be decoded are found in the "Supported VPD pages" VPD
page. Pages that cannot be decoded are displayed in hex; add the
--long option to have ASCII displayed to the right of each line of
If this option is used with the --inhex=FN option then the file
FN is assumed to contain 1 or more VPD pages (in ASCII hex or
binary). Decoding continues until the file is exhausted (or an error
occurs). Sanity checks are aplied on each VPD page's length and the
ascending order of VPD page numbers (required by SPC-4) so bad data may be
If the --page=PG option is also given then no VPD page whose page
number is greater than PG (or its numeric equivalent) is
- -e, --enumerate
- list the names of the known VPD pages, first the standard
pages (i.e. those defined by T10), then the vendor specific pages. Each
group is sorted in abbreviation order. The DEVICE and most other
options are ignored and this utility exits after listing the VPD page
names. May be used together with --page=PG where PG is
numeric. If so, it searches for the summary lines of all VPD pages whose
number matches PG. May be used with --vendor=VP to restrict
output to known vendor specific pages for vendor/product VP.
- -h, --help
- outputs the usage message summarizing command line options
then exits. Ignores DEVICE if given.
- -H, --hex
- outputs the requested VPD page in ASCII hexadecimal. Can be
used multiple times, see section on the ATA information vpd page.
To generate output suitable for placing in a file that can be used by a
later invocation with the --inhex=FN option, use the '-HHHH' option
(e.g. 'sg_vpd -p di -HHHH /dev/sg3 > dev_id.hex'). The reason '-HHHH'
is used is to flag that unadorned hexadecimal (without other text or
address offsets) is sent to stdout.
- -i, --ident
- decode the device identification (0x83) VPD page. When used
once this option has the same effect as '--page=di'. When use twice then
the short form of the device identification VPD page's logical unit
designator is decoded. In the latter case this option has the same effect
as '--quiet --page=di_lu'.
- -I, --inhex=FN
- FN is expected to be a file name (or '-' for stdin)
which contains ASCII hexadecimal or binary representing a VPD page (or a
standard INQUIRY) response. This utility will then decode that response.
It is preferable to also supply the --page=PG option, if not this
utility will attempt to guess which VPD page (or standard INQUIRY) the
response is associated with. The hexadecimal should be arranged as 1 or 2
digits representing a byte each of which is whitespace or comma separated.
Anything from and including a hash mark to the end of line is ignored. If
the --raw option is also given then FN is treated as
- -l, --long
- when decoding some VPD pages, give a little more output.
For example the ATA Information VPD page only shows the signature (in hex)
and the IDENTIFY (PACKET) DEVICE (in hex) when this option is given.
- -m, --maxlen=LEN
- where LEN is the (maximum) response length in bytes.
It is placed in the cdb's "allocation length" field. If not
given (or LEN is zero) then 252 is used (apart from the ATA
Information VPD page which defaults to 572) and, if the response indicates
this value is insufficient, another INQUIRY command is sent with a larger
value in the cdb's "allocation length" field. If this option is
given and LEN is greater than 0 then only one INQUIRY command is
sent. Since many simple devices implement the INQUIRY command badly (and
do not support VPD pages) then the safest value to use for LEN is
36. See the sg_inq man page for the more information.
- -p, --page=PG
- where PG is the VPD page to be decoded or output.
The PG argument can either be an abbreviation, a number or a pair
or numbers/abbreviations separated by a comma. The VPD page abbreviations
can be seen by using the --enumerate option. If a number is given
it is assumed to be decimal unless it has a hexadecimal indicator which is
either a leading '0x' or a trailing 'h'. If one number is given then it is
assumed to be a VPD page number. If two numbers (or abbreviations) are
given then the second one is the same as VP (see the
--vendor=VP option). If this option is not given (nor '-i', '-l'
nor '-V') then the "Supported VPD pages" (0x0) VPD page is
fetched and decoded. If PG is '-1' or 'sinq' then the standard
INQUIRY response is output. This option may also be used with the
--enumerate (see its description).
- -q, --quiet
- suppress the amount of decoding output.
- -r, --raw
- if not used with --inhex=FN then output requested
VPD page in binary. The output should be piped to a file or another
utility when this option is used. The binary is sent to stdout, and errors
are sent to stderr.
if used with --inhex=FN then the contents of FN is treated as
- -M, --vendor=VP
- where VP is a vendor (e.g. "sea" for
Seagate) or vendor/product acronym (e.g. "hp3par" for the 3PAR
array from HP). Many vendors have re-used the numbers at the beginning of
the vendor specific VPD page range (e.g. page 0xc0) and this option is a
way of selecting only those which are of interest. Using a VP of
"xxx" will list the available acronyms.
If this option is used with --page=PG and PG is an acronym
then this option is ignored. If PG is a number (e.g. 0xc0) then
VP is used to choose the which vendor specific page (e.g. sharing
page number 0xc0) to decode.
- -v, --verbose
- increases the level or verbosity.
- -V, --version
- print out version string then exit.
This VPD page (0x89 or 'ai') is defined by the SCSI to ATA Translation standard.
It contains information about the SAT layer, the "signature" of the
ATA device and the response to the ATA IDENTIFY (PACKET) DEVICE command. The
latter part has 512 bytes of identity, capability and settings data which the
hdparm utility is capable of decoding (so this utility doesn't decode it).
To unclutter the output for this page, the signature and the IDENTIFY (PACKET)
DEVICE response are not output unless the --long
) are given. When the --long
given the IDENTIFY (PACKET) DEVICE response is output as 256 (16 bit) words as
is the fashion for ATA devices. To see that response as a string of bytes use
the '-HH' option. To format the output suitable for hdparm to decode use
either the '-HHH' or '-rr' option. For example if 'dev/sdb' is a SATA disk
behind a SAT layer then this command: 'sg_vpd -p ai -HHH /dev/sdb | hdparm
--Istdin' should decode the ATA IDENTIFY (PACKET) DEVICE response.
Since some VPD pages (e.g. the Extended INQUIRY page) depend on settings in the
standard INQUIRY response, then the standard INQUIRY response is output as a
pseudo VPD page when PG
is set to '-1' or 'sinq'. Also the decoding of
some fields (e.g. the Extended INQUIRY page's SPT field) is expanded when the
'--long' option is given using the standard INQUIRY response information (e.g.
the PDT and the PROTECT fields).
In the 2.4 series of Linux kernels the DEVICE
must be a SCSI generic (sg)
device. In the 2.6 series block devices (e.g. disks and ATAPI DVDs) can also
be specified. For example "sg_inq /dev/sda" will work in the 2.6
series kernels. From lk 2.6.6 other SCSI "char" device names may be
used as well (e.g. "/dev/st0m").
is opened with a read-only flag (e.g. in Unix with the
The exit status of sg_vpd is 0 when it is successful. Otherwise see the
sg3_utils(8) man page.
The examples in this page use Linux device names. For suitable device names in
other supported Operating Systems see the sg3_utils(8) man page.
To see the VPD pages that a device supports, use with no options. The command
line invocation is shown first followed by a typical response:
# sg_vpd /dev/sdb
Supported VPD pages VPD page:
Supported VPD pages [sv]
Unit serial number [sn]
Device identification [di]
Extended inquiry data [ei]
Block limits (SBC) [bl]
To see the VPD page numbers associated with each supported page then add the
'--long' option to the above command line. To view a VPD page either its
number or abbreviation can be given to the '--page=' option. The page name
abbreviations are shown within square brackets above. In the next example the
Extended inquiry data VPD page is listed:
# sg_vpd --page=ei /dev/sdb
extended INQUIRY data VPD page:
ACTIVATE_MICROCODE=0 SPT=0 GRD_CHK=0 APP_CHK=0 REF_CHK=0
UASK_SUP=0 GROUP_SUP=0 PRIOR_SUP=0 HEADSUP=1 ORDSUP=1 SIMPSUP=1
WU_SUP=0 CRD_SUP=0 NV_SUP=0 V_SUP=0
P_I_I_SUP=0 LUICLR=0 R_SUP=0 CBCS=0
Multi I_T nexus microcode download=0
Extended self-test completion minutes=0
POA_SUP=0 HRA_SUP=0 VSA_SUP=0
To check if any protection types are supported by a disk use the '--long' option
on the Extended inquiry data VPD page:
# sg_vpd --page=ei --long /dev/sdb
extended INQUIRY data VPD page:
SPT=1 [protection types 1 and 2 supported]
Search for the name (and acronym) of all pages that share VPD page number 0xb0 .
# sg_vpd --page=0xb0 --enumerate
Matching standard VPD pages:
bl 0xb0 Block limits (SBC)
oi 0xb0 OSD information
sad 0xb0 Sequential access device capabilities (SSC)
Some examples follow using the "--all" option. Send an ASCII
hexadecimal representation of all VPD pages to a file:
# sg_vpd --all -HHHH /dev/sg3 > all_vpds.hex
At some later time that file could be decoded with:
# sg_vpd --all --inhex=all_vpds.hex
To do the equivalent as the previous example but use a file containing binary:
# sg_vpd --all --raw /dev/sg3 > all_vpds.bin
# sg_vpd --all --raw --inhex=all_vpds.bin
Notice that "--raw" must be given with the second (--inhex) invocation
to alert the utility that all_vpds.bin contains binary as it assumes ASCII
hexadecimal by default. Next we only decode T10 specified VPD pages excluding
vendor specific VPD pages that start at page number 0xc0:
# sg_vpd --all --page=0xbf --raw --inhex=all_vpds.bin
Further examples can be found on the http://sg.danny.cz/sg/sg3_utils.html web
Written by Douglas Gilbert
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2006-2016 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not
even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
sg_inq(sg3_utils), sg3_utils(sg3_utils), sdparm(sdparm),