sg_modes
(1m)
Name
sg_modes - reads mode pages with SCSI MODE SENSE command
Synopsis
sg_modes [--all] [--control=PC] [--dbd] [--dbout] [--exam-
ine] [--flexible] [--help] [--hex] [--list] [--llbaa]
[--maxlen=LEN] [--page=PG[,SPG]] [--raw] [-R] [--six]
[--verbose] [--version] [DEVICE]
sg_modes [-6] [-a] [-A] [-c=PC] [-d] [-D] [-e] [-f] [-h]
[-H] [-l] [-L] [-m=LEN] [-p=PG[,SPG]] [-r] [-subp=SPG] [-v]
[-V] [-?] [DEVICE]
Description
SG3_UTILS SG_MODES(8)
NAME
sg_modes - reads mode pages with SCSI MODE SENSE command
SYNOPSIS
sg_modes [--all] [--control=PC] [--dbd] [--dbout] [--exam-
ine] [--flexible] [--help] [--hex] [--list] [--llbaa]
[--maxlen=LEN] [--page=PG[,SPG]] [--raw] [-R] [--six]
[--verbose] [--version] [DEVICE]
sg_modes [-6] [-a] [-A] [-c=PC] [-d] [-D] [-e] [-f] [-h]
[-H] [-l] [-L] [-m=LEN] [-p=PG[,SPG]] [-r] [-subp=SPG] [-v]
[-V] [-?] [DEVICE]
DESCRIPTION
This utility sends a MODE SENSE SCSI command to the DEVICE
and outputs the response. There is a 6 byte and 10 byte
(cdb) variant of the MODE SENSE command, this utility
defaults to the 10 byte variant.
This utility decodes mode page headers and block descriptors
but outputs the contents of each mode page in hex. It also
has no facility to change the mode page contents or block
descriptor data. Mode page contents are decoded and can be
changed by the sdparm utility.
This utility supports two command line syntaxes, the pre-
ferred one is shown first in the synopsis and explained in
this section. A later section on the old command line syntax
outlines the second group of options.
If no page is given (and --list is not selected) then --all
is assumed. The --all option requests all mode pages (but
not subpages) in a single response.
OPTIONS
Arguments to long options are mandatory for short options as
well.
-a, --all
output all the mode pages reported by the DEVICE. This
is what the page code 63 (0x3f) is defined to do. When
used once, mode subpages are not fetched. When used
twice (e.g. '-aa'), all mode pages and subpages are
requested which is equivalent to '--page=63,255'.
-c, --control=PC
PC is the page control value. Up to four different ver-
sions of each page are held by the device:
0 : current values (i.e. those active at present)
1 : changeable values
2 : default values (i.e. the manufacturer's settings)
3 : saved values
sg3_utils-1.26 Last change: January 2008 1
SG3_UTILS SG_MODES(8)
The changeable values are bit masks showing which
fields could be changed with a MODE SELECT. The saved
values will be re-instated the next time the device is
power cycled or reset. If this option is not given then
current values [0] are assumed.
-d, --dbd
disable block descriptors. By default, block descrip-
tors (usually one (for disks) or none) are returned in
a MODE SENSE response. This option sets the "disable
block descriptors" (DBD) bit in the cdb which instructs
the device not to return any block descriptors in its
response. Older devices may not support this setting
and may return an "illegal request" sense key; alterna-
tively they may ignore it. Oddly the Reduced Block Com-
mand set (RBC) requires this bit set.
-D, --dbout
disable outputting block descriptors. Irrespective of
whether block descriptors are present in the response
or not, they are not output.
-e, --examine
examine each mode page in the range 0 through to 62
(inclusive). If some response is given then print out
the mode page name or number (in hex) if the name is
not known.
-f, --flexible
Some devices, bridges and/or drivers attempt crude
translations between MODE SENSE 6 and 10 byte commands
without correcting the response. This will cause the
response to be mis-interpreted (usually with an error
saying the response is malformed). With this option,
the length of the response is checked, and if it looks
wrong, the response is then decoded as if the other
mode sense (cdb length) was sent.
-h, --help
print out the usage message then exit.
-H, --hex
The default action is to decode known mode page numbers
(and subpage numbers) into text. When this option is
used once, the response is output in hexadecimal. When
this option is used twice, mode page numbers and page
control values are output in hex.
-l, --list
lists all common page and subpage codes and their names
that are found in the command set that matches the
peripheral type of the given DEVICE. If no DEVICE and
sg3_utils-1.26 Last change: January 2008 2
SG3_UTILS SG_MODES(8)
no --page=PG is given then the common page and subpage
codes and their names are listed for SBC (e.g. a disk).
If no DEVICE is given and a --page=PG is given then the
common page and subpage codes and their names are
listed for the command set whose peripheral device type
matches the value given to PG. For example 'sg_mode
--list --page=1' lists the command mode pages and sub-
pages for tape devices. Additionally if a sub_page_code
is given then it is interpreted as a transport identi-
fier and command transport specific mode page codes and
their names are listed following the main mode page
list. Other options are ignored.
-L, --llbaa
set the Long LBA Accepted (LLBAA) bit in the MODE SENSE
(10) cdb. This bit is not defined in the MODE SENSE (6)
cdb so setting the '-L' and '--six' options is reported
as an error. When set the DEVICE may respond with 16
byte block descriptors as indicated by the 'LongLBA'
field in the response. In most cases setting this
option is not needed.
-m, --maxlen=LEN
The LEN argument is the maximum response length in
bytes. It is the 'allocation length' field in the cdb.
When not given (or LEN is zero) then the allocation
length field is set to 4096 for MODE SENSE (10) or 252
for MODE SENSE (6). The LEN argument must be non-nega-
tive and no greater than 65535 for MODE SENSE (10) and
not greater than 255 for MODE SENSE (6).
-O, --old
switch to older style options.
-p, --page=PG
page code to fetch. The PG is assumed to be a decimal
value unless prefixed by '0x' or has a trailing 'h'. It
should be a value between 0 and 63 (inclusive). When
not given and a default is required then a value of 63
(0x3f), which fetches all mode pages, is used.
-p, --page=PG,SPG
page code and subpage code values to fetch. Both argu-
ments are assumed to be decimal unless flagged as hexa-
decimal. The page code should be between 0 and 63
inclusive. The subpage code should be between 0 and 255
inclusive. The default value for the subpage code is 0.
-r, --raw
output the response in binary to stdout. Error messages
and warnings, if any, are sent to stderr. When this
option is used twice (e.g. '-rr') then has the same
sg3_utils-1.26 Last change: January 2008 3
SG3_UTILS SG_MODES(8)
action as '-R'
-R output the selected mode page to stdout a byte per
line. Each line contains two hexadecimal digits (e.g.
"3e"). Useful as input (after editing) to the
sg_wr_mode(8) utility.
-6, --six
by default this utility sends a 10 byte MODE SENSE com-
mand to the DEVICE. However some SCSI devices only sup-
port 6 byte MODE SENSE commands (e.g. SCSI-2 tape
drives). This parameter forces the use of 6 byte MODE
SENSE commands.
-v, --verbose
increase level of verbosity. Can be used multiple
times.
-V, --version
print out version string then exit.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | system/storage/sg3_utils |
+---------------+--------------------------+
|Stability | Uncommitted |
+---------------+--------------------------+
NOTES
If the normal sg_modes utility fails with "illegal command
operation code" then try the '--six' (or '-6') option.
This utility performs a SCSI INQUIRY command to determine
the peripheral type of the device (e.g. 0 -> Direct Access
Device (disk)) prior to sending a MODE SENSE command. This
helps in decoding the block descriptor and mode pages.
In the 2.4 series of Linux kernels the DEVICE must be a SCSI
generic (sg) device. In the 2.6 series block devices (e.g.
SCSI disks and DVD drives) can also be specified. For exam-
ple "sg_modes -a /dev/sda" will work in the 2.6 series ker-
nels.
EXIT STATUS
The exit status of sg_modes is 0 when it is successful. Oth-
erwise see the sg3_utils(8) man page.
sg3_utils-1.26 Last change: January 2008 4
SG3_UTILS SG_MODES(8)
OLDER COMMAND LINE OPTIONS
The options in this section were the only ones available
prior to sg3_utils version 1.23 . In sg3_utils version 1.23
and later these older options can be selected by either set-
ting the SG3_UTILS_OLD_OPTS environment variable or using
'--old' (or '-O) as the first option.
-6 by default this utility sends a 10 byte MODE SENSE com-
mand to the DEVICE. This parameter forces the use of 6
byte MODE SENSE commands. See --six in the main
description.
-a see --all in the main description.
-A output all the mode pages and subpages supported by the
DEVICE. Same as '--all --all' in the new syntax.
-c=PC
PC is the page control value. See --control=PC in the
main description.
-d see --dbd in the main description.
-D see --dbout in the main description.
-e see --examine in the main description.
-f see --flexible in the main description.
-h The default action is to decode known mode page numbers
(and subpage numbers) into text. With this option mode
page numbers (and subpage numbers) are output in hexa-
decimal.
-H same action as the '-h' option.
-l see --list in the main description.
-L see --llbaa in the main description.
-N switch to the newer style options.
-m=LEN
see --maxlen=LEN in the main description.
-p=PG
PG is page code to fetch. Should be a hexadecimal num-
ber between 0 and 3f inclusive (0 to 63 decimal). The
default value when required is 3f (fetch all mode
pages).
-p=PG,SPG
sg3_utils-1.26 Last change: January 2008 5
SG3_UTILS SG_MODES(8)
page code and subpage code values to fetch. The page
code should be a hexadecimal number between 0 and 3f
inclusive. The subpage code should be a hexadecimal
number between 0 and ff inclusive. The default value
for the subpage code is 0.
-r output the selected mode page to stdout a byte per
line. Each line contains two hexadecimal digits (e.g.
"3e"). Useful as input (after editing) to the
sg_wr_mode(8) utility.
-subp=SPG
sub page code to fetch. Should be a hexadecimal number
between 0 and 0xff inclusive. The default value is 0.
-v increase verbosity of output.
-V print out version string then exit.
-? output usage message then exit. Ignore all other param-
eters.
AUTHOR
Written by Doug Gilbert
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2000-2008 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
sdparm(8), sg_wr_mode(8), sginfo(8), sgmode(scsirastools),
scsiinfo(net), scu(net), seatools(seagate)
All these utilities offer some facility to change mode page
(or block descriptor) parameters.
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-1.26 Last change: January 2008 6