This utility fetches a Vital Product Data page and decodes it or
outputs it in ASCII hexadecimal or binary. VPD pages are fetched
with a SCSI INQUIRY command.
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 option.
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
list the names of the known VPD pages, first the standard pages, then the
vendor specific pages. Each group is sorted in abbreviation order. The
DEVICE and other options are ignored and this utility exits afte
listing the VPD page names.
outputs the usage message summarizing command line options then exits.
Ignores DEVICE if given.
outputs the requested VPD page in ASCII hexadecimal. Can be used multiple
times, see section on the ATA information vpd page.
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'.
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.
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.
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 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 are given the second number indicates which vendor specific VPD page
to decode when several pages share the same VPD page number. If this option
is not given (nor '-i', '-l' nor '-V') then the "Supported VPD pages" (0x0)
VPD page is fetched and decoded.
suppress the amount of decoding output.
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.
increases the level or verbosity.
print out version string then exit.
ATA INFORMATION VPD PAGE
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 option (or
--hex or --raw) are given. When the --long option
is 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.
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").
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.