sg_read_long - send a SCSI READ LONG command
sg_read_long [--16] [--correct] [--help] [--lba=LBA] [--out=OF] [--pblock] [--readonly] [--verbose] [--version] [--xfer_len=BTL] DEVICE
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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | system/storage/sg3_utils |
+---------------+--------------------------+
|Stability | Uncommitted |
+---------------+--------------------------+
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 (C) 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
This software was built from source available at
https://java.net/projects/solaris-userland. The original community
source was downloaded from http://sg.danny.cz/sg/p/sg3_utils-1.33.tgz
Further information about this software can be found on the open source
community website at http://sg.danny.cz/sg/sg3_utils.html.
sg3_utils-1.30 April 2010 SG_READ_LONG(8)