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]   [--extended]   [--feature=FEA]   [--help]  [--lba=LBA]
       [--len={16|12}] [--readonly] [--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
       sat3r05b.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 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, --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.

       -e, --extended
              allow for extended LBA numbers (i.e. larger than 32 bits).  This value  is  enabled  automatically
              for large LBA numbers, but can be enabled explicitly even for low LBA numbers with this option.

       -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, --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.

       -r, --readonly
              causes the DEVICE to be opened with the read-only flag (O_RDONLY in Unix). The default  action  is
              to  open  DEVICE with the read-write flag (O_RDWR in Unix). In some cases sending power management
              commands to ATA disks are defeated by OS actions on the close() if the DEVICE was opened with  the
              read-write flag (e.g. the OS might think it needs to flush something to disk).

       -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 © 2007-2014 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)