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  option-
       ally 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 PUR-
       POSE.

SEE ALSO

       sg_reassign, sg_write_long, sg_dd

sg3_utils-1.30							    April 2010							   SG_READ_LONG(8)