NAME

       sg_scan - scans sg devices (or SCSI/ATAPI/ATA devices) and prints results

SYNOPSIS

       sg_scan [-a] [-i] [-n] [-w] [-x] [DEVICE]*

DESCRIPTION

       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.

       In Linux 2.6 and 3 series kernels, the lsscsi utility may be helpful. Apart from providing
       more information (by data-mining in the sysfs pseudo file system), it does not  need  root
       permissions to execute, as this utility would typically need.

OPTIONS

       -a     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 series.

       -i     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

       -n     do numeric scan (i.e. sg0, sg1...) [default]

       -w     use a read/write flag when opening sg device (default is read-only)

       -x     extra information output about queueing

NOTES

       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 inclusive.

EXIT STATUS

       The  exit status of sg_scan is 0 when it is successful. Otherwise see the sg3_utils(8) man
       page.

AUTHORS

       Written by D. Gilbert and F. Jansen

COPYRIGHT

       Copyright © 1999-2013 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

       lsscsi(8)