SG_SAT_SET_FEATURES(8) SG3_UTILS SG_SAT_SET_FEATURES(8)
NAME
sg_sat_set_features - use ATA SET FEATURES command via a SCSI to ATA Translation (SAT) layer
SYNOPSIS
sg_sat_set_features [--count=CO] [--ck_cond] [--feature=FEA] [--help] [--lba=LBA] [--len={16|12}] [--verbose] [--version] DEVICE
DESCRIPTION
This utility sends an ATA SET FEATURES command to the DEVICE. This command is used to change settings of ATA non-packet (i.e. disks) and
packet devices (e.g. cd/dvd drives). Rather than send the SET FEATURES command directly to the device it is sent via a SCSI transport which
is assumed to contain a SCSI to ATA Translation (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) defines 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-2 is also a standard:
SAT-2 ANSI INCITS 465-2010 and the draft prior to that is sat2r09.pdf . The SAT-3 project has started and the most recent draft is
sat3r01.pdf .
The features can be read using the sg_sat_identify utility which uses either the ATA IDENTIFY DEVICE (for non-packet devices) or the IDEN-
TIFY PACKET DEVICE (for packet devices) command.
OPTIONS
Arguments to long options are mandatory for short options as well.
-c, --count=CO
the number CO is placed in the "count" field in the ATA SET FEATURES command. Only some subcommands (a term used for the value
placed in the "feature" field) require the count field to be set. The default value placed in the "count" field is 0.
-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 descriptor irrespective of whether the ATA command succeeded or failed. When clear the SATL should
only yield a sense buffer containing a ATA Result descriptor if the ATA command failed.
-f, --feature=FEA
the value FEA is placed in the "feature" field in the ATA SET FEATURES command. The term "subcommand" is sometimes used for this
value. The default value placed in the "feature" field is 0 which is reserved and hence should not change anything. Two common exam-
ples are 2h to enable the write cache and 82h to disable it.
-h, --help
outputs the usage message summarizing command line options then exits. Ignores DEVICE if given.
-L, --lba=LBA
the number LBA is placed in the "lba" field of the ATA SET FEATURES command. Only some sub-commands (a term used for the value
placed in the "feature" field) require the lba field to be set. This value is typically not a "logical block address" as the acronym
might imply. The default value placed in the "lba" field is 0. The maximum value allowed for LBA is 0xfffffffe (or 0xffffff if
--len=12).
-l, --len={16|12}
this is the length of the SCSI cdb used for the ATA PASS-THROUGH commands. The argument can either be 16 or 12. The default is 16.
Some SCSI transports cannot convey SCSI commands longer than 12 bytes.
-v, --verbose
increases the level or verbosity.
-V, --version
print out version string
NOTES
In the 2.4 series of Linux kernels the DEVICE must be a SCSI generic (sg) device. In the 2.6 and 3 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"). Prior to lk 2.6.29 USB mass storage limited sense data to 18 bytes which made the
--ck_cond option yield strange (truncated) results.
EXIT STATUS
The exit status of sg_sat_set_features 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) 2007-2013 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
POSE.
SEE ALSO
sg_sat_identify(sg3_utils), sg_inq(sg3_utils), sdparm(sdparm), hdparm(hdparm)
sg3_utils-1.37 June 2013 SG_SAT_SET_FEATURES(8)