sg_modes.8


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.TH SG_MODES "8" "March 2003" "sg3_utils-1.03" SG3_UTILS
.SH NAME
sg_modes \- reads SCSI MODE SENSE pages
.SH SYNOPSIS
.B sg_modes
[\fI-a\fR] [\fI-c=<page_control>\fR] [\fI-d\fR] [\fI-h\fR] [\fI-l\fR]
[\fI-p=<page_code>\fR] [\fI-V\fR] [\fI-6\fR] [\fI-?\fR] [\fI<sg_device>\fR]
.SH DESCRIPTION
.\" Add any additional description here
.PP
This command sends a MODE SENSE SCSI command (the 10 byte variant)
to the given device and then outputs the response. There is no facility
to change the page or descriptor data with this command.
.TP
-a
lists all the mode pages supported by the device.
.TP
-c=page_control
up to four different versions os each page are held by the device:
the current values [0] are the default (i.e. when this parameter is
not given), the changeable values [1] (bit mask showing which parts
could be changed with a MODE SELECT), default value [2] (from the
manufacturer?) and saved values [4] (when this device was last power
cycled?).
.TP
-d
disable block descriptors. By default MODE SENSE returns in its response
block descriptors and this parameter can be used to suppress them.
.TP
-h
currently only suppresses the printing out of known page code descriptions
.TP
-l
lists all known page codes. These are mainly for direct access 
devices (disks) and those that apply to all devices. Ignores the given
device and most other parameters.
.TP
-p=<page_code>
page code to fetch. Should be a hexadecimal number between 0 and 0x3f
inclusive.
.TP
-V
print out version string
.TP
-6
by default this command sends out a 10 byte MODE SENSE command. However
some SCSI devices only support 6 byte MODE SENSE commands (e.g. SCSI-2
tape drives). This parameter forces the use of 6 byte MODE SENSE commands.
.TP
-?
output usage message. Ignore all other parameters.
.PP
If the normal sg_modes command fails with "illegal command
operation code" then try the "-6" parameter. To alter page settings
see the program listed in the "See Also" section below.
.PP
This command 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.
.PP
In the 2.4 series of Linux kernels the given device must be
a SCSI generic (sg) device. In the 2.5 series block devices (e.g. disks
and SCSI DVDs) can also be specified. For example "sg_modes -a /dev/sda"
will work in the 2.5 series kernels.
.SH AUTHOR
Written by Doug Gilbert
.SH "REPORTING BUGS"
Report bugs to <dgilbert@interlog.com>.
.SH COPYRIGHT
Copyright \(co 2000-2003 Douglas Gilbert
.br
This software is distributed under the GPL version 2. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
.SH "SEE ALSO"
.B sginfo(this package), sgmode(scsirastools), scsiinfo(see net), scu(see net)