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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 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.

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 (C) 2004-2010 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-1.30                    April 2010                   SG_READ_LONG(8)