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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 log‐
	      ical 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  suf‐
       fixes  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	 capa‐
       ble  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 © 2004-2010 Douglas Gilbert
       This  software is distributed under the GPL version 2. There is NO war‐
       ranty; 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)

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