sg_read_long
(1m)
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
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 (typ-
ically 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
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SG3_UTILS SG_READ_LONG(8)
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.
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 num-
ber of elements in the "grown" defect list could be moni-
tored (with "sg_reassign --grown") as the disk could be
nearing the end of its useful lifetime.
Various numeric arguments (e.g. LBA) may include multiplica-
tive 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.]
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SG3_UTILS SG_READ_LONG(8)
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
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.
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