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SG_SAT_IDENTIFY(8) SG3_UTILS SG_SAT_IDENTIFY(8)
NAME
sg_sat_identify - send ATA IDENTIFY DEVICE command via SCSI to ATA Translation (SAT) layer
SYNOPSIS
sg_sat_identify [--ck_cond] [--extend] [--help] [--hex] [--ident] [--len=CLEN] [--packet]
[--raw] [--readonly] [--verbose] [--version] DEVICE
DESCRIPTION
This utility sends either an ATA IDENTIFY DEVICE command or an ATA IDENTIFY PACKET DEVICE
command to DEVICE and outputs the response. The devices that respond to these commands are
ATA disks and ATAPI devices respectively. Rather than send these commands directly to the
device they are sent via a SCSI transport which is assumed to contain a SCSI to ATA Trans-
lation (SAT) Layer (SATL). The SATL may be in an operating system driver, in host bus
adapter firmware or in some external enclosure.
The SAT standard (SAT ANSI INCITS 431-2007, prior draft: sat-r09.pdf at www.t10.org) de-
fines two SCSI "ATA PASS-THROUGH" commands: one using a 16 byte "cdb" and the other with a
12 byte cdb. This utility defaults to using the 16 byte cdb variant. SAT-4 revision 5
added a SCSI "ATA PASS-THROUGH(32)" command. SAT-2 and SAT-3 are now also standards: SAT-2
ANSI INCITS 465-2010 and SAT3 ANSI INCITS 517-2015 . The SAT-4 project is near standard-
ization and the most recent draft is sat4r06.pdf .
OPTIONS
Arguments to long options are mandatory for short options as well.
-c, --ck_cond
sets the CK_COND bit in the ATA PASS-THROUGH SCSI cdb. The default setting is clear
(i.e. 0). When set the SATL should yield a sense buffer containing a ATA Result de-
scriptor irrespective of whether the command succeeded or failed. When clear the
SATL should only yield a sense buffer containing a ATA Result descriptor if the
command failed.
-e, --extend
sets the EXTEND bit in the ATA PASS-THROUGH SCSI cdb. The default setting is clear
(i.e. 0). When set a 48 bit LBA command is sent to the device. This option has no
effect when --len=12.
-h, --help
outputs the usage message summarizing command line options then exits. Ignores DE-
VICE if given.
-H, --hex
outputs the ATA IDENTIFY (PACKET) DEVICE response in hex. The default action (i.e.
without any '-H' options) is to output the response in hex, grouped in 16 bit words
(i.e. the ATA standard's preference). When given once, the response is output in
ASCII hex bytes (i.e. the SCSI standard's preference). When given twice (i.e.
'-HH') the output is in hex, grouped in 16 bit words, the same as the default but
without a header. When given thrice (i.e. '-HHH') the output is in hex, grouped in
16 bit words, in a format that is acceptable for 'hdparm --Istdin' to process.
'-HHHH' simply outputs hex data bytes, space separated, 16 per line.
-i, --ident
outputs the World Wide Name (WWN) of the device. This should be a NAA-5 64 bit num-
ber. It is output in hex prefixed with "0x". If not available then
"0x0000000000000000" is output. The equivalent for a SCSI disk (i.e. its logical
unit name) can be found with "sg_vpd -ii".
-l, --len=CLEN
CLEN this is the length of the SCSI cdb used for the ATA PASS-THROUGH command.
CLEN can either be 12, 16 or 32. The default is 16. The larger cdb sizes are needed
for 48 bit LBA addressing of ATA devices. The ATA Auxiliary and ICC registers are
only conveyed with the 32 byte cdb variant.
-p, --packet
send an ATA IDENTIFY PACKET DEVICE command (via the SATL). The default action is to
send an ATA IDENTIFY DEVICE command. Note that the ATAPI specification by T13 (i.e.
the PACKET interface) is now obsolete.
-r, --raw
output the ATA IDENTIFY (PACKET) DEVICE response 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.
-R, --readonly
open the DEVICE read-only (e.g. in Unix with the O_RDONLY flag). The default is to
open it read-write.
-v, --verbose
increases the level or verbosity.
-V, --version
print out version string
NOTES
Since the response to the IDENTIFY (PACKET) DEVICE command is very important for the cor-
rect use of an ATA(PI) device (and is typically the first command sent), a SATL should
provide an ATA Information VPD page which contains the similar information.
The SCSI ATA PASS-THROUGH (12) command's opcode is 0xa1 and it clashes with the MMC set's
BLANK command used by cd/dvd writers. So a SATL in front of an ATAPI device that uses MMC
(i.e. has peripheral device type 5) probably should treat opcode 0xa1 as a BLANK command
and send it through to the cd/dvd drive. The ATA PASS-THROUGH (16) command's opcode (0x85)
does not clash with anything so it is a better choice.
Prior to Linux kernel 2.6.29 USB mass storage limited sense data to 18 bytes which made
the --ck_cond option yield strange (truncated) results.
EXAMPLES
These examples use Linux device names and a Linux utility called hdparm. For suitable de-
vice names in other supported Operating Systems see the sg3_utils(8) man page.
In this example /dev/sdb is a SATA 2.5" disk connected via a USB (type C connector) dongle
that implements the UAS (USB attached SCSI) protocol (also known as UASP). UAS is a vast
improvement over the USB mass storage class.
# sg_sat_identify /dev/sdb
Response for IDENTIFY DEVICE ATA command:
00 0c5a 3fff c837 0010 0000 0000 003f 0000 .Z ?. .7 .. .. .. .? ..
....
The hexadecimal ASCII (with plain ASCII to the right) output is abridged to a single line
(i.e. the first 16 bytes (or 8 words)). Now to decode some of that ATA Identify response.
First sg_inq can decode a few strings:
# sg_sat_identify -HHHH /dev/sdb | sg_inq --ata -I -
ATA device: model, serial number and firmware revision:
ST9500420AS 5VJCE6R7 0002SDM1
For a lot more details, the hdparm utility is a good choice:
# sg_sat_identify -HHH /dev/sdb | hdparm --Istdin
ATA device, with non-removable media
Model Number: ST9500420AS
Serial Number: 5VJCE6R7
Firmware Revision: 0002SDM1
Transport: Serial
Standards:
....
There are about 80 more lines of details decoded by hdparm in this case. Notice the dif-
ference in the number of "H" options: three give an unadorned hex output arranged in (lit-
tle endian) words (i.e. 16 bits each) while four "H" options give an unadorned hex output
in bytes (i.e. 8 bits each).
EXIT STATUS
The exit status of sg_sat_identify is 0 when it is successful. Otherwise see the
sg3_utils(8) man page.
AUTHOR
Written by Douglas Gilbert
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2006-2018 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_inq(sg3_utils), sdparm(sdparm), hdparm(hdparm)
sg3_utils-1.43 January 2018 SG_SAT_IDENTIFY(8)
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