sg_vpd - fetches Vital Product Data (VPD) pages using a SCSI INQUIRY
sg_vpd [--enumerate] [--help] [--hex] [--ident] [--long] [--maxlen=LEN]
[--page=PG] [--quiet] [--raw] [--verbose] [--version] DEVICE
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
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
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
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
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)
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.
Written by Doug Gilbert
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2006-2008 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
sg_inq(sg3_utils), sdparm(sdparm), hdparm(hdparm)