bionic (8) sg_decode_sense.8.gz

NAME

       sg_decode_sense - decode SCSI sense data

SYNOPSIS

       sg_decode_sense   [--binary=FN]   [--file=FN]  [--help]  [--hex]  [--nospace]  [--status=SS]  [--verbose]
       [--version] [--write=WFN] [H1 H2 H3 ...]

DESCRIPTION

       This utility takes SCSI sense data in binary or as a sequence of ASCII hexadecimal bytes and decodes  it.
       The  primary  reference  for  the  decoding is SPC-3 ANSI INCITS 408-2005 and the most recent draft SPC-4
       revision 37 which can be found at http://www.t10.org and other locations on the internet.

       SCSI sense data is often found in kernel log files as a result of something going wrong but may  just  be
       informative.  It  is  often shown as a sequence of hexadecimal bytes, starting with 70, 71, 72, 73, f0 or
       f1.  Sense data could be up to 252 bytes long but typically is much shorter than that, 18 bytes  long  is
       often seen and is usually associated with the older "fixed" format sense data.

       The  sense  data can be provided on the command line or in a file. If given on the command line the sense
       data should be a sequence of hexadecimal bytes separated by space. Alternatively a file can be given with
       the  contents  in  binary or ASCII hexadecimal bytes. The latter form can contain several lines each with
       none, one or more ASCII hexadecimal bytes separated by space (comma or tab). The hash symbol  may  appear
       and it and the rest of the line is ignored making it useful for comments.

OPTIONS

       Arguments to long options are mandatory for short options as well.

       -b, --binary=FN
              the sense data is read in binary from a file called FN.

       -h, --help
              output the usage message then exit.

       -H, --hex
              this  option  is used in conjunction with --write=WFN in order to change the output written to WFN
              to lines of ASCII hex bytes suitable for a C language compiler. Each line contains up to 16  bytes
              (e.g. a line starting with "0x3b,0x07,0x00,0xff").

       -f, --file=FN
              the  sense  data is read in ASCII hexadecimal from a file called FN.  The sense data should appear
              as a sequence of bytes separated by space, comma, tab or newline. Everything from and including  a
              hash  symbol to the end of that line is ignored. If --nospace is set then no separator is required
              between the ASCII hexadecimal digits in FN with bytes decoded  from  pairs  of  ASCII  hexadecimal
              digits.

       -n, --nospace
              expect  ASCII  hexadecimal to be a string of hexadecimal digits with no spaces between them. Bytes
              are decoded by taking two hexadecimal digits at a time, so an even number of digits  is  expected.
              The  string  of  hexadecimal  digits  may  be on the command line (replacing "H1 H2 H3") or spread
              across multiple lines the FN given to --file=.  On the command line, spaces (or  other  whitespace
              characters)  between  sequences  of  hexadecimal  digits are ignored; the maximum command line hex
              string is 1023 characters long.

       -s, --status=SS
              where SS is a SCSI status byte value, given in hexadecimal. The SCSI status byte is related to but
              distinct from sense data.

       -v, --verbose
              increase the degree of verbosity (debug messages).

       -V, --version
              output version string then exit.

       -w, --write=WFN
              writes the sense data out to a file called WFN. If necessary WFN is created. If WFN exists then it
              is truncated prior to writing the sense data to it. If the --hex option is also given  then  ASCII
              hex is written to WFN (see the --hex option description); otherwise binary is written to WFN. This
              option is a convenience and may be helpful in converting the ASCII hexadecimal  representation  of
              sense data (or anything else) into the equivalent binary or a compilable ASCII hex form.

NOTES

       Unlike  most  utilities  in this package, this utility does not access a SCSI device (logical unit). This
       utility accesses a library associated with this package. Amongst other things the  library  decodes  SCSI
       sense data.

       T10  defined  SCSI  command  names  given  a  CDB can be decoded using the sg_raw utility with the '-vvv'
       option.

EXAMPLES

       Sense data is often printed out in kernel logs and sometimes on the command line when  verbose  or  debug
       flags  are  given.  It will be at least 8 bytes long, often 18 bytes long but may be longer. A sense data
       string might look like this:

       f0 00 03 00 00 12 34 0a  00 00 00 00 11 00 00 00
       00 00

       Cut and paste it after the sg_decode_sense command:

         sg_decode_sense f0 00 03 00 00 12 34 0a 00 00 00 00 11 00 00 00 00 00

       and for this sense data the output should look like this:

        Fixed format, current;  Sense key: Medium Error
        Additional sense: Unrecovered read error
         Info fld=0x1234 [4660]

       For a medium error the Info field is the logical block address (LBA) of the lowest  numbered  block  that
       the associated SCSI command was not able to read (verify or write).

EXIT STATUS

       The exit status of sg_decode_sense is 0 when it is successful. Otherwise see the sg3_utils(8) man page.

AUTHORS

       Written by Douglas Gilbert.

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright © 2010-2014 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_requests,sg_raw(sg3_utils)