SG_WRITE_BUFFER(8) SG3_UTILS SG_WRITE_BUFFER(8)
sg_write_buffer - send a SCSI WRITE BUFFER command
sg_write_buffer [--help] [--id=ID] [--in=FILE] [--length=LEN] [--mode=MO] [--offset=OFF]
[--raw] [--skip=SKIP] [--verbose] [--version] DEVICE
Sends a SCSI WRITE BUFFER command to DEVICE, along with data provided by the user. In some
cases no data is required, or data can be read from the file given in the --in=FILE
option, or data is read from stdin when either --raw or --in=- is given.
Some WRITE BUFFER command variants do not have associated data to send to the device, for
example "activate_mc" ("activate deferred microcode").
Arguments to long options are mandatory for short options as well.
output the usage message then exit. If used multiple times also prints the mode
names and their acronyms.
this option sets the buffer id field in the cdb. ID is a value between 0 (default)
and 255 inclusive.
read data from file FILE that will be sent with the WRITE BUFFER command. If FILE
is '-' then stdin is read until an EOF is detected (this is the same action as
where LEN is the length, in bytes, of data to be written to the device. If not
given (and length cannot be deduced from --in=FILE or --raw) then defaults to zero.
If the option is given and the length deduced from --in=FILE or --raw is less (or
no data is provided), then bytes of 0xff are used as fill bytes.
this option sets the mode field in the cdb. MO is a value between 0 (default) and
31 inclusive. Alternatively an abbreviation can be given. To list the available
mode abbreviations give an invalid one (e.g. '--mode=xxx') or use the '-hh' option.
this option sets the buffer offset field in the cdb. OFF is a value between 0
(default) and 2**24-1 . It is a byte offset.
read data from stdin until an EOF is detected. This data is sent with the WRITE
BUFFER command to DEVICE. The action of this option is the same as using '--in=-'.
this option is only active when --in=FILE is given and FILE is a regular file,
rather than stdin. Data is read starting at byte offset SKIP to the end of file (or
the amount given by --length=LEN). If not given the byte offset defaults to 0 (i.e.
the start of the file).
increase the level of verbosity, (i.e. debug output).
print the version string and then exit.
If no --length=LEN is given this utility reads up to 8 MiB of data from the given file
FILE (or stdin). If a larger amount of data is required then the --length=LEN option
should be given. The user should be aware that most operating systems have limits on the
amount of data that can be sent with one SCSI command. In Linux this depends on the pass
through mechanism used (e.g. block SG_IO or the sg driver) and various setting in sysfs in
the linux lk 2.6 series (e.g. /sys/block/sda/queue/max_sectors_kb).
Downloading incorrect microcode into a device has the ability to render that device inop-
erable. One would hope that the device vendor verifies the data before activating it. If
the SCSI WRITE BUFFER command is given values in its cdb (e.g. LEN) that are inappropriate
(e.g. too large) then the device should respond with a sense key of ILLEGAL REQUEST and an
additional sense code of INVALID FIELD in CDB. If a WRITE BUFFER command (or a sequence of
them) fails due to device vendor verification checks then it should respond with a sense
key of ILLEGAL REQUEST and an additional sense code of COMMAND SEQUENCE ERROR.
All numbers given with options are assumed to be decimal. Alternatively numerical values
can be given in hexadecimal preceded by either "0x" or "0X" (or has a trailing "h" or
The exit status of sg_write_buffer is 0 when it is successful. Otherwise see the
sg3_utils(8) man page.
Written by Luben Tuikov and Douglas Gilbert.
Report bugs to <dgilbert at interlog dot com>.
Copyright (C) 2006-2007 Luben Tuikov and Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not even for
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
sg3_utils-1.23 January 2007 SG_WRITE_BUFFER(8)