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SG_READ_LONG(8)                             SG3_UTILS                             SG_READ_LONG(8)

NAME
       sg_read_long - send a SCSI READ LONG command

SYNOPSIS
       sg_read_long  [--16]  [--correct]  [--help] [--lba=LBA] [--out=OF] [--pblock] [--readonly]
       [--verbose] [--version] [--xfer_len=BTL] DEVICE

DESCRIPTION
       Send SCSI READ LONG command to DEVICE. The read buffer is output in hex and ASCII to  std-
       out or placed in a file. Note that the data returned includes the logical block data (typ-
       ically 512 bytes for a disk) plus ECC information (whose format is proprietary)  plus  op-
       tionally  other  proprietary  data. Note that the logical block data may be encoded or en-
       crypted.

       In SBC-4 revision 7 the SCSI READ LONG (10 and 16 byte) commands were  made  obsolete.  In
       the same revision all uses of SCSI WRITE LONG (10 and 16 byte) commands were made obsolete
       apart from the case in which the WR_UNCOR bit is set.

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

       -S, --16
              uses a SCSI READ LONG(16) command. The  default  action  is  to  use  a  SCSI  READ
              LONG(10)  command.  The  READ LONG(10) command has a 32 bit field for the lba while
              READ LONG(16) has a 64 bit field.

       -c, --correct
              sets the 'CORRCT' bit in the SCSI READ LONG command. When set the data is corrected
              by  the  ECC before being transferred back to this utility. The default is to leave
              the 'CORRCT' bit clear in which case the data is not corrected.

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

       -l, --lba=LBA
              where LBA is the logical block address of the sector to read. Assumed to be in dec-
              imal  unless  prefixed with '0x' (or has a trailing 'h'). Defaults to lba 0. If the
              lba is larger than can fit in 32 bits then the --16 option should be used.

       -o, --out=OF
              instead of outputting ASCII hex to stdout, send it in binary to the file called OF.
              If  '-'  is  given for OF then the (binary) output is sent to stdout. Note that all
              informative and error output is sent to stderr.

       -p, --pblock
              sets the 'PBLOCK' bit in the SCSI READ LONG command. When set  the  physical  block
              (plus ECC data) containing the requested logical block address is read. The default
              is to leave the 'PBLOCK' bit clear in which case the logical block  (plus  any  ECC
              data) is read.

       -r, --readonly
              opens  the  DEVICE read-only rather than read-write which is the default. The Linux
              sg driver needs read-write access for the SCSI READ LONG command but  other  access
              methods may require read-only access.

       -v, --verbose
              increase the level of verbosity, (i.e. debug output).

       -V, --version
              print the version string and then exit.

       -x, --xfer_len=BTL
              where  BTL is the byte transfer length (default to 520). If the given value (or the
              default) does not match the "long" block size of the device, the appropriate BTL is
              deduced  from the error response and printed (to stderr). The idea is that the user
              will retry this utility with the correct transfer length.

NOTES
       If a defective block is found and its contents, if any, has been retrieved then  "sg_reas-
       sign"  could  be  used  to map out the defective block. Associated with such an action the
       number of elements in the "grown"  defect  list  could  be  monitored  (with  "sg_reassign
       --grown") as the disk could be nearing the end of its useful lifetime.

       Various  numeric  arguments  (e.g. LBA) may include multiplicative suffixes or be given in
       hexadecimal. See the "NUMERIC ARGUMENTS" section in the sg3_utils(8) man page.

       As a data point, Fujitsu uses a 54 byte ECC (per block) which is capable of correcting  up
       to  a  single  burst  error or 216 bits "on the fly". [Information obtained from MAV20xxrc
       product manual.]

EXIT STATUS
       The exit status of sg_read_long 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 (C) 2004-2016 Douglas Gilbert
       This  software  is distributed under the GPL version 2. There is NO warranty; not even for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO
       sg_reassign, sg_write_long, sg_dd

sg3_utils-1.42                            November 2015                           SG_READ_LONG(8)

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