sg_scan - does a scan of sg devices (or given SCSI/ATAPI/ATA devices) and
prints the results
If no DEVICE names are given, sg_scan does a scan of the sg
devices and outputs a line of information for each sg device that is
currently bound to a SCSI device. If one or more DEVICEs are given
only those devices are scanned.
Each device is opened with the O_NONBLOCK flag so that the scan will
not "hang" on any device that another process holds an O_EXCL lock on.
Any given DEVICE name is expected to comply
with (to some extent) the Storage Architecture Model (SAM see www.t10.org).
Any device names associated with the Linux SCSI subsystem (e.g. /dev/sda
and /dev/st0m) are suitable. Devices names associated with ATAPI
devices (e.g. most CD/DVD drives and ATAPI tape drives) are also suitable.
If the device does not fall into the above categories then an ATA
IDENTIFY command is tried.
do alphabetical scan (i.e. sga, sgb, sgc). Note that sg device nodes with
an alphabetical index have been deprecated since the linux kernel 2.2
do a SCSI INQUIRY, output results in a second (indented) line. If the device
is an ATA disk then output information from an ATA IDENTIFY command
do numeric scan (i.e. sg0, sg1...) [default]
use a read/write flag when opening sg device (default is read-only)
extra information output about queuing
This utility was written at a time when hotplugging of SCSI devices
was not supported in Linux. It used a simple algorithm to scan sg
device nodes in ascending numeric or alphabetical order, stopping
after there were 4 consecutive errors.
In the linux kernel 2.6 series, this utility uses sysfs to find which
sg device nodes are active and only checks those. Hence there can be
large "holes" in the numbering of sg device nodes (e.g. after an
adapter has been removed) and still all active sg device nodes will
be listed. This utility assumes that sg device nodes are named using
the normal conventions and searches from /dev/sg0 to /dev/sg4095
The exit status of sg_scan is 0 when it is successful. Otherwise see
the sg3_utils(8) man page.