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
       stdout  or  placed  in a file. Note that the data returned includes the logical block data
       (typically 512 bytes for a disk) plus ECC information (whose format is  proprietary)  plus
       optionally  other  proprietary  data.  Note  that the logical block data may be encoded or
       encrypted.

       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
              decimal  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_reassign" 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 © 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