NAME
sg_sat_set_features - sends a ATA SET FEATURES command via a SCSI to
ATA Translation (SAT) layer
SYNOPSIS
sg_sat_set_features [--count=CO] [--chk_cond] [--feature=FEA] [--help]
[--len=16|12] [--lba=LBA] [--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
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 the 16 byte cdb variant.
The SATL may be in an operating system driver, in host bus adapter
firmware or in some external enclosure.
The features can be read using the sg_sat_identify utility which uses
either the ATA IDENTIFY DEVICE (for non-packet devices) or the IDENTIFY
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, --chk_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 examples 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, --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.
-L, --lba=LBA
the number LBA is placed in the "lba" field in the ATA SET
FEATURES command. Only some subcommands (a term used for the
value placed in the "feature" field) require the lba field to be
set. This value is not a "logical block address" as the acronym
might imply. The default value placed in the "lba" field is 0.
-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 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").
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 Doug Gilbert
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright © 2007 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_sat_identify(sg3_utils), sg_inq(sg3_utils), sdparm(sdparm),
hdparm(hdparm)