sg_scan(8)

1SG_SCAN(8)                         SG3_UTILS                        SG_SCAN(8)
2
3
4

NAME

6       sg_scan  -  scans  sg  devices  (or  SCSI/ATAPI/ATA devices) and prints
7       results
8

SYNOPSIS

10       sg_scan [-a] [-i] [-n] [-w] [-x] [DEVICE]*
11

DESCRIPTION

13       If no DEVICE names are given, sg_scan does a scan of the sg devices and
14       outputs  a  line  of  information  for each sg device that is currently
15       bound to a SCSI device. If one or more DEVICEs  are  given  only  those
16       devices are scanned.  Each device is opened with the O_NONBLOCK flag so
17       that the scan will not "hang" on any device that another process  holds
18       an O_EXCL lock on.
19
20       Any  given  DEVICE name is expected to comply with (to some extent) the
21       Storage Architecture Model (SAM see  www.t10.org).   Any  device  names
22       associated  with the Linux SCSI subsystem (e.g. /dev/sda and /dev/st0m)
23       are suitable. Devices names associated with ATAPI  devices  (e.g.  most
24       CD/DVD  drives and ATAPI tape drives) are also suitable.  If the device
25       does not fall into the above categories then an ATA IDENTIFY command is
26       tried.
27
28       In  Linux  2.6 and 3 series kernels, the lsscsi utility may be helpful.
29       Apart from providing more information  (by  data-mining  in  the  sysfs
30       pseudo  file  system), it does not need root permissions to execute, as
31       this utility would typically need.
32

OPTIONS

34       -a     do alphabetical scan (i.e. sga, sgb, sgc). Note that  sg  device
35              nodes  with an alphabetical index have been deprecated since the
36              Linux kernel 2.2 series.
37
38       -i     do a SCSI INQUIRY, output results in a second  (indented)  line.
39              If the device is an ATA disk then output information from an ATA
40              IDENTIFY command
41
42       -n     do numeric scan (i.e. sg0, sg1...) [default]
43
44       -w     use a  read/write  flag  when  opening  sg  device  (default  is
45              read-only)
46
47       -x     extra information output about queueing
48

NOTES

50       This utility was written at a time when hotplugging of SCSI devices was
51       not supported in Linux. It used a simple algorithm to  scan  sg  device
52       nodes  in ascending numeric or alphabetical order, stopping after there
53       were 4 consecutive errors.
54
55       In the Linux kernel 2.6 series, this utility uses sysfs to  find  which
56       sg  device  nodes  are active and only checks those. Hence there can be
57       large "holes" in the numbering  of  sg  device  nodes  (e.g.  after  an
58       adapter  has been removed) and still all active sg device nodes will be
59       listed. This utility assumes that sg device nodes are named  using  the
60       normal conventions and searches from /dev/sg0 to /dev/sg4095 inclusive.
61

EXIT STATUS

63       The  exit  status  of sg_scan is 0 when it is successful. Otherwise see
64       the sg3_utils(8) man page.
65

AUTHORS

67       Written by D. Gilbert and F. Jansen
68

COPYRIGHT

70       Copyright © 1999-2013 Douglas Gilbert
71       This software is distributed under the GPL version 2. There is NO  war‐
72       ranty;  not  even  for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
73       POSE.
74