1SGINFO(8) SG3_UTILS SGINFO(8)
2
6 sginfo - access mode page information for a SCSI (or ATAPI) device
7
9 sginfo [OPTIONS] [DEVICE] [REPLACEMENT_PARAMETERS]
10
12 sginfo is a port of the Linux scsiinfo program by Eric Youngdale. It
13 uses SCSI generic (sg) devices; however in some cases the high level
14 device name (i.e. sd, sr, st, osst, or hd) can also be used. The pri‐
15 mary role of this program is to access mode page information. If per‐
16 mitted, mode page information can be altered. In addition information
17 from the INQUIRY and READ DEFECTS commands are also available.
18 This utility is in legacy mode, only obvious bugs will be fixed.
20 Options like -l (to list devices) are broken in recent versions of
21 Linux (e.g. 2.6 series and later); the lsscsi(8) utility can be used
22 instead. Also mode pages are not being updated as http://www.t10.org
23 adds and modifies mode page fields. Those interested in SCSI mode pages
24 may find the sdparm utility more up to date and easier use, especially
25 for changing parameters.
26 Four sets of values are maintained by a SCSI device for each mode page:
28 current (active), default (manufacturer's supplied values), saved (val‐
29 ues that are retained if the SCSI device is powered down), and change‐
30 able (mask indicating those values that can be changed). By default
31 when a mode page is displayed the current values are shown. This can be
32 overridden by "-M" (defaults), "-S" (saved) or "-m" (modifiable (i.e.
33 changeable)).
34 Many mode pages are decoded: for disks (see SBC-2), for CD/DVDs (see
36 MMC-2/3/4/5), for tapes (see SSC-2) and for enclosures (see SES-2).
37 Some mode pages common to all SCSI peripheral device types are defined
38 in SPC-4 (primary commands). A decoded mode page has its field names in
39 the first column and the corresponding value in the second column. A
40 "hex" mode page (and subpage) has its byte position in the first column
41 (in hex and starting at 0x2) and the corresponding hex value in the
42 second column. Decoded pages can be viewed with the '-t' option or with
43 a specific option (e.g. 'c' for the caching mode page). Naturally
44 decoded pages must be supplied by the DEVICE and recognised by this
45 program. If supported by the device, decoded pages may be modified. All
46 mode pages (and subpages) that the device supports can be viewed in hex
47 (and potentially modified) via the "-u" option
48 If no options are given that will cause mode page(s) or INQUIRY data to
50 be printed out, then a brief INQUIRY response is output. This includes
51 the vendor, product and revision level of the device.
52
54 -6 Perform 6 byte MODE SENSE and MODE SELECT commands; by default
55 the 10 byte variants are used.
56 -a Display some INQUIRY data and the unit serial number followed by
58 all mode pages reported by the device. It is similar to the '-t
59 0x3f' option. If the mode page is known then it is output in
60 decoded form otherwise it is output in hexadecimal.
61 -A Display some INQUIRY data and the unit serial number followed by
63 all mode pages and all mode subpages reported by the device. It
64 is similar to the '-t 0x3f,0xff' option. If a mode (sub)page is
65 known then it is output in decoded form otherwise it is output
66 in hexadecimal.
67 -c Access information in the Caching mode page.
69 -C Access information in the Control mode Page.
71 -d Display defect lists (default format: index).
73 -D Access information in the Disconnect-Reconnect mode page.
75 -e Access information in the Error Recovery mode page.
77 -E Access information in the Control Extension mode page.
79 -f Access information in the Format Device mode page.
81 -Farg Format of the defect lists:
83 -Flogical - logical block addresses (32 bit)
84 -Flba64 - logical block addresses (64 bit)
85 -Fphysical - physical blocks
86 -Findex - defect bytes from index
87 -Fhead - sort by head
88 Used in conjunction with "-d" or "-G". If a format is not given
89 "index" is assumed.
90 -g Access information in the Rigid Disk Drive Geometry mode page.
92 -G Display grown defect list (default format: index).
94 -i Display the response to a standard INQUIRY command.
96 -I Access the Informational Exceptions mode page.
98 -l Deprecated. Only use in old versions of Linux (e.g. 2.4 and ear‐
100 lier). Please use lsscsi(8) in the Linux 2.6 series and later.
101 List known SCSI devices on the system.
102 -n Access information in the Notch and Partition mode page.
104 -N Negate (i.e. stop) mode page changes being placed in the "saved"
106 page (by default changes go to the current and the saved page).
107 Only active when used together with '-R'.
108 -P Access information in the Power Condition mode page.
110 -r Display all raw (or primary) SCSI device names visible in the
112 /dev directory. Examples are /dev/sda, /dev/st1 and /dev/scd2.
113 Does not list sg device names so devices such as a SCSI enclo‐
114 sure which only have an sg device name are not listed.
115 -s Display information in the unit serial number page which is a
117 INQUIRY command variant.
118 -t PN[,SPN]
120 Display information from mode page number PN (and optionally sub
121 page number SPN) in decoded format (if known, otherwise in hex
122 form). PN is a mode page number in a decimal number from 0 to
123 63 inclusive. SPN is the mode subpage number and is assumed to
124 be 0 if not given. SPN is a decimal number from 1 to 255 inclu‐
125 sive. A page number of 63 returns all pages supported by the
126 device in ascending order except for page 0 which, if present,
127 is last. Page 0 is vendor specific and not necessarily in mode
128 page format. Alternatively hex values can be given for both PN
129 and SPN (both prefixed by '0x').
130 -T Trace commands to obtain more verbose output (for debugging).
132 When used once SCSI commands are shown (in hex) and any errors
133 from these SCSI commands are spelt out (i.e. with a decoded and
134 raw sense buffer). When used twice, the additional data sent
135 with mode select and the response from mode sense are shown (in
136 hex).
137 -u PN[,SPN]
139 Display information from mode page number PN (and optionally
140 SPN) in hex form. PN is a mode page number in a decimal number
141 from 0 to 63 inclusive. SPN is the mode subpage number and is
142 assumed to be 0 if not given. SPN is a decimal number from 1 to
143 255 inclusive. A page number of 63 returns all pages supported
144 by the device in ascending order except for page 0 which, if
145 present, is last. Page 0 is vendor specific and not necessarily
146 in mode page format. Alternatively hex values can be given for
147 both PN and SPN (both prefixed by '0x'). For example 63 and 0x3f
148 are equivalent.
149 -v Display version string then exit. [N.B. This option increases
151 verbosity for most other utilities in this package as outlined
152 in 'man 8 sg3_utils'. This odd usage is for backward compati‐
153 bility with the scsiinfo utility.]
154 -V Access information in the Verify Error Recovery mode page. [N.B.
156 This option prints the version string then exits in most other
157 utilities in this package as outlined in 'man 8 sg3_utils'. This
158 odd usage is for backward compatibility with the scsiinfo util‐
159 ity.]
160 -z do a single fetch for mode pages (over-estimating the expected
162 length of the returned response). The default action is to do a
163 double fetch, the first fetch is to find the response length
164 that could be returned. Devices that closely adhere to SCSI
165 standards should not require this option, some real world
166 devices do require it.
167
169 Only one of the following three options can be specified. None of
170 these three implies the current values are returned.
171 -m Display modifiable fields instead of current values
173 -M Display manufacturer's defaults instead of current values
175 -S Display saved defaults instead of current values
177 The following are advanced options, not generally suited for most
179 users:
180 -X Display output values in a list. Make them suitable for editing
182 and being given back to the '-R' (replace command).
183 -R Replace parameters - best used with -X (expert use only)
185
187 Firstly you should know what you are doing before changing existing
188 parameters. Taking the control page as an example, first list it out
189 normally (e.g. "sginfo -C /dev/sda") and decide which parameter is to
190 be changed (note its position relative to the other lines output). Then
191 execute the same sginfo command with the "-X" option added; this will
192 output the parameter values in a single row in the same relative posi‐
193 tions as the previous command. Now execute "sginfo -CXR /dev/sda ..."
194 with the "..." replaced by the single row of values output by the pre‐
195 vious command, with the relevant parameter changed. Here is a simpli‐
196 fied example:
197 $ sginfo -C /dev/sda
199 Control mode page (0xa)
200 -----------------------
201 TST 0
202 D_SENSE 0
203 GLTSD 1
204 RLEC 0
205 [Actually the Control page has more parameters that shown above.] Next
207 output those parameters in single line form:
208 $ sginfo -CX /dev/sda
210 0 0 1 0
211 Let us assume that the GLTSD bit is to be cleared. The command that
213 will clear it is:
214 $ sginfo -CXR /dev/sda 0 0 0 0
216 The same number of parameters output by the "-CX" command needs to be
218 placed at the end of the "-CXR" command line (after the device name).
219 Now check that the change took effect:
220 $ sginfo -C /dev/sda
222 Control mode page (0xa)
223 -----------------------
224 TST 0
225 D_SENSE 0
226 GLTSD 0
227 RLEC 0
228 When a mode page is "replaced" the default action is to change both the
230 current page and the saved page. [For some reason versions of sginfo
231 and scsiinfo prior to 2.0 did not change the "saved" page.] To change
232 only the current mode page but not the corresponding saved page use the
233 "-N" option.
234
236 The "-aX" or "-AX" option generates output suitable for a script file.
237 Mode pages are output in list format (after the INQUIRY and serial num‐
238 ber) one page per line. To facilitate running the output as (part of) a
239 script file to assert chosen mode page values, each line is prefixed by
240 "sginfo -t PN[,SPN] -XR ". When such a script file is run, it will have
241 the effect of re-asserting the mode page values to what they were when
242 the "-aX" generated the output.
243 All mode pages (and subpages) supported by the device can be accessed
245 via the -t and -u options. To see all mode pages supported by the
246 device use "-u 63". [To see all mode pages and all subpages use "-u
247 63,255".] To list the control mode page in hex (mode page index in the
248 first column and the corresponding byte value in the second column) use
249 "-u 0xa". Mode pages (subpage code == 0) start at index position 2
250 while subpages start at index position 4. If the "-Xu ..." option is
251 used then a list a hex values each value prefixed by "@" is output.
252 Mode (sub)page values can then be modified with the "-RXu ..." option.
253
255 The SCSI MODE SENSE command yields block descriptors as well as a mode
256 page(s). This utility ignores block descriptors and does not display
257 them. The "disable block descriptor" switch (DBD) in the MODE SENSE
258 command is not set since some devices yield errors when it is set. When
259 mode page values are being changed (the "-R" option), the same block
260 descriptor obtained by reading the mode page (i.e. via a MODE SENSE
261 command) is sent back when the mode page is written (i.e. via a MODE
262 SELECT command).
263
265 SCSI (draft) standards can be found at http://www.t10.org . The rele‐
266 vant documents are SPC-4 (mode pages common to all device types), SBC-2
267 (direct access devices [e.g. disks]), MMC-4 (CDs and DVDs) and SSC-2
268 (tapes).
269
271 Written by Eric Youngdale, Michael Weller, Douglas Gilbert, Kurt
272 Garloff, Thomas Steudten
273
275 scsiinfo version 1.0 was released by Eric Youngdale on 1st November
276 1993. The most recent version of scsiinfo is version 1.7 with the last
277 patches by Michael Weller. sginfo is derived from scsiinfo and uses the
278 sg interface to get around the 4 KB buffer limit in scsiinfo that
279 cramped the display of defect lists especially. sginfo was written by
280 Douglas Gilbert with patches from Kurt Garloff. This manpage corre‐
281 sponds with version 2.25 of sginfo.
282 This software is distributed under the GPL version 2. There is NO war‐
284 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
285 POSE.
286
288 lsscsi(lsscsi), scsiinfo(internet); sg_modes, sg_inq, sg_vpd
289 (sg3_utils), sdparm(sdparm)
290sg3_utils-1.38 January 2014 SGINFO(8)