Documentation/scsi/scsi-generic.rst

4 SCSI Generic (sg) driver
11 The SCSI Generic driver (sg) is one of the four "high level" SCSI device
12 drivers along with sd, st and sr (disk, tape and CD-ROM respectively). Sg
15 Thus sg is used for scanners, CD writers and reading audio CDs digitally
23 Major versions of the sg driver
25 There are three major versions of sg found in the Linux kernel (lk):
26       - sg version 1 (original) from 1992 to early 1999 (lk 2.2.5) .
28       - sg version 2 from lk 2.2.6 in the 2.2 series. It is based on
30       - sg version 3 found in the lk 2.4 series (and the lk 2.5 series).
34 Sg driver documentation
36 The most recent documentation of the sg driver is kept at
38 - https://sg.danny.cz/sg/
40 This describes the sg version 3 driver found in the lk 2.4 series.
42 Documentation (large version) for the version 2 sg driver found in the
45 - https://sg.danny.cz/sg/p/scsi-generic_long.txt.
47 The original documentation for the sg driver (prior to lk 2.2.6) can be
52 A more general description of the Linux SCSI subsystem of which sg is a
58 There are two packages of sg utilities:
61     sg3_utils   for the sg version 3 driver found in lk 2.4
62     sg_utils    for the sg version 2 (and original) driver found in lk 2.2
67 capabilities. They can be found at: https://sg.danny.cz/sg/sg3_utils.html and
70 Another approach is to look at the applications that use the sg driver.
74 Mapping of Linux kernel versions to sg driver versions
77 of the sg driver:
79      - lk 2.4.0 : sg version 3.1.17
80      - lk 2.4.7 : sg version 3.1.19
81      - lk 2.4.10 : sg version 3.1.20 [#]_
82      - lk 2.4.17 : sg version 3.1.22
84 .. [#] There were 3 changes to sg version 3.1.20 by third parties in the
88 the new version of the sg driver:
90      - lk 2.2.0 : original sg version [with no version number]
91      - lk 2.2.6 : sg version 2.1.31
92      - lk 2.2.8 : sg version 2.1.32
93      - lk 2.2.10 : sg version 2.1.34 [SG_GET_VERSION_NUM ioctl first appeared]
94      - lk 2.2.14 : sg version 2.1.36
95      - lk 2.2.16 : sg version 2.1.38
96      - lk 2.2.17 : sg version 2.1.39
97      - lk 2.2.20 : sg version 2.1.40
99 The lk 2.5 development series currently contains sg version 3.5.23
100 which is functionally equivalent to sg version 3.1.22 found in lk 2.4.17.