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 Those interested in SCSI mode pages may find the sdparm utility easier
20 use, especially for changing parameters. Also the author considers this
21 utility legacy so the mode pages are not being updated as
22 http://www.t10.org adds and modifies mode page fields.
23 Four sets of values are maintained by a SCSI device for each mode page:
25 current (active), default (manufacturer's supplied values), saved (val‐
26 ues that are retained if the SCSI device is powered down), and change‐
27 able (mask indicating those values that can be changed). By default
28 when a mode page is displayed the current values are shown. This can be
29 overridden by "-M" (defaults), "-S" (saved) or "-m" (modifiable (i.e.
30 changeable)).
31 Many mode pages are decoded: for disks (see SBC-2), for CD/DVDs (see
33 MMC-2/3/4/5), for tapes (see SSC-2) and for enclosures (see SES-2).
34 Some mode pages common to all SCSI peripheral device types are defined
35 in SPC-4 (primary commands). A decoded mode page has its field names in
36 the first column and the corresponding value in the second column. A
37 "hex" mode page (and subpage) has its byte position in the first column
38 (in hex and starting at 0x2) and the corresponding hex value in the
39 second column. Decoded pages can be viewed with the '-t' option or with
40 a specific option (e.g. 'c' for the caching mode page). Naturally
41 decoded pages must be supplied by the DEVICE and recognised by this
42 program. If supported by the device, decoded pages may be modified. All
43 mode pages (and subpages) that the device supports can be viewed in hex
44 (and potentially modified) via the "-u" option
45 If no options are given that will cause mode page(s) or INQUIRY data to
47 be printed out, then a brief INQUIRY response is output. This includes
48 the vendor, product and revision level of the device.
49
51 -6 Perform 6 byte MODE SENSE and MODE SELECT commands; by default
52 the 10 byte variants are used.
53 -a Display some INQUIRY data and the unit serial number followed by
55 all mode pages reported by the device. It is similar to the '-t
56 0x3f' option. If the mode page is known then it is output in
57 decoded form otherwise it is output in hexadecimal.
58 -A Display some INQUIRY data and the unit serial number followed by
60 all mode pages and all mode subpages reported by the device. It
61 is similar to the '-t 0x3f,0xff' option. If a mode (sub)page is
62 known then it is output in decoded form otherwise it is output
63 in hexadecimal.
64 -c Access information in the Caching mode page.
66 -C Access information in the Control mode Page.
68 -d Display defect lists (default format: index).
70 -D Access information in the Disconnect-Reconnect mode page.
72 -e Access information in the Error Recovery mode page.
74 -E Access information in the Control Extension mode page.
76 -f Access information in the Format Device mode page.
78 -Farg Format of the defect lists:
80 -Flogical - logical block addresses (32 bit)
81 -Flba64 - logical block addresses (64 bit)
82 -Fphysical - physical blocks
83 -Findex - defect bytes from index
84 -Fhead - sort by head
85 Used in conjunction with "-d" or "-G". If a format is not given
86 "index" is assumed.
87 -g Access information in the Rigid Disk Drive Geometry mode page.
89 -G Display grown defect list (default format: index).
91 -i Display the response to a standard INQUIRY command.
93 -I Access the Informational Exceptions mode page.
95 -l List known SCSI devices on the system.
97 -n Access information in the Notch and Partition mode page.
99 -N Negate (i.e. stop) mode page changes being placed in the "saved"
101 page (by default changes go to the current and the saved page).
102 Only active when used together with '-R'.
103 -P Access information in the Power Condition mode page.
105 -r Display all raw (or primary) SCSI device names visible in the
107 /dev directory. Examples are /dev/sda, /dev/st1 and /dev/scd2.
108 Does not list sg device names so devices such as a SCSI enclo‐
109 sure which only have an sg device name are not listed.
110 -s Display information in the unit serial number page which is a
112 INQUIRY command variant.
113 -t PN[,SPN]
115 Display information from mode page number PN (and optionally sub
116 page number SPN) in decoded format (if known, otherwise in hex
117 form). PN is a mode page number in a decimal number from 0 to
118 63 inclusive. SPN is the mode subpage number and is assumed to
119 be 0 if not given. SPN is a decimal number from 1 to 255 inclu‐
120 sive. A page number of 63 returns all pages supported by the
121 device in ascending order except for page 0 which, if present,
122 is last. Page 0 is vendor specific and not necessarily in mode
123 page format. Alternatively hex values can be given for both PN
124 and SPN (both prefixed by '0x').
125 -t Trace commands (for debugging). When used once SCSI commands are
127 shown (in hex) and any errors from these SCSI commands are spelt
128 out (i.e. with a decoded and raw sense buffer). When used
129 twice, the additional data sent with mode select and the
130 response from mode sense are shown (in hex).
131 -u PN[,SPN]
133 Display information from mode page number PN (and optionally
134 SPN) in hex form. PNis a mode page number in a decimal number
135 from 0 to 63 inclusive. SPN is the mode subpage number and is
136 assumed to be 0 if not given. SPN is a decimal number from 1 to
137 255 inclusive. A page number of 63 returns all pages supported
138 by the device in ascending order except for page 0 which, if
139 present, is last. Page 0 is vendor specific and not necessarily
140 in mode page format. Alternatively hex values can be given for
141 both PN and SPN (both prefixed by '0x'). For example 63 and 0x3f
142 are equivalent.
143 -v Display version string then exit. [N.B. This option increases
145 verbosity for most other utilities in this package as outlined
146 in 'man 8 sg3_utils'. This odd usage is for backward compati‐
147 bility with the scsiinfo utility.]
148 -V Access information in the Verify Error Recovery mode page. [N.B.
150 This option prints the version string then exits in most other
151 utilities in this package as outlined in 'man 8 sg3_utils'. This
152 odd usage is for backward compatibility with the scsiinfo util‐
153 ity.]
154 -z do a single fetch for mode pages (over-estimating the expected
156 length of the returned response). The default action is to do a
157 double fetch, the first fetch is to find the response length
158 that could be returned. Devices that closely adhere to SCSI
159 standards should not require this option, some real world
160 devices do require it.
161
163 Only one of the following three options can be specified. None of
164 these three implies the current values are returned.
165 -m Display modifiable fields instead of current values
167 -M Display manufacturer's defaults instead of current values
169 -S Display saved defaults instead of current values
171 The following are advanced options, not generally suited for most
173 users:
174 -X Display output values in a list. Make them suitable for editing
176 and being given back to the '-R' (replace command).
177 \-R Replace parameters - best used with -X (expert use only)
179
181 Firstly you should know what you are doing before changing existing
182 parameters. Taking the control page as an example, first list it out
183 normally (e.g. "sginfo -C /dev/sda") and decide which parameter is to
184 be changed (note its position relative to the other lines output). Then
185 execute the same sginfo command with the "-X" option added; this will
186 output the parameter values in a single row in the same relative posi‐
187 tions as the previous command. Now execute "sginfo -CXR /dev/sda ..."
188 with the "..." replaced by the single row of values output by the pre‐
189 vious command, with the relevant parameter changed. Here is a simpli‐
190 fied example:
191 $ sginfo -C /dev/sda
193 Control mode page (0xa)
194 -----------------------
195 TST 0
196 D_SENSE 0
197 GLTSD 1
198 RLEC 0
199 [Actually the Control page has more parameters that shown above.] Next
201 output those parameters in single line form:
202 $ sginfo -CX /dev/sda
204 0 0 1 0
205 Let us assume that the GLTSD bit is to be cleared. The command that
207 will clear it is:
208 $ sginfo -CXR /dev/sda 0 0 0 0
210 The same number of parameters output by the "-CX" command needs to be
212 placed at the end of the "-CXR" command line (after the device name).
213 Now check that the change took effect:
214 $ sginfo -C /dev/sda
216 Control mode page (0xa)
217 -----------------------
218 TST 0
219 D_SENSE 0
220 GLTSD 0
221 RLEC 0
222 When a mode page is "replaced" the default action is to change both the
224 current page and the saved page. [For some reason versions of sginfo
225 and scsiinfo prior to 2.0 did not change the "saved" page.] To change
226 only the current mode page but not the corresponding saved page use the
227 "-N" option.
228
230 The "-aX" or "-AX" option generates output suitable for a script file.
231 Mode pages are output in list format (after the INQUIRY and serial num‐
232 ber) one page per line. To facilitate running the output as (part of) a
233 script file to assert chosen mode page values, each line is prefixed by
234 "sginfo -t PN[,SPN] -XR ". When such a script file is run, it will have
235 the effect of re-asserting the mode page values to what they were when
236 the "-aX" generated the output.
237 All mode pages (and subpages) supported by the device can be accessed
239 via the -t and -u options. To see all mode pages supported by the
240 device use "-u 63". [To see all mode pages and all subpages use "-u
241 63,255".] To list the control mode page in hex (mode page index in the
242 first column and the corresponding byte value in the second column) use
243 "-u 0xa". Mode pages (subpage code == 0) start at index position 2
244 while subpages start at index position 4. If the "-Xu ..." option is
245 used then a list a hex values each value prefixed by "@" is output.
246 Mode (sub)page values can then be modified with with the "-RXu ..."
247 option.
248
250 The SCSI MODE SENSE command yields block descriptors as well as a mode
251 page(s). This utility ignores block descriptors and does not display
252 them. The "disable block descriptor" switch (DBD) in the MODE SENSE
253 command is not set since some devices yield errors when it is set. When
254 mode page values are being changed (the "-R" option), the same block
255 descriptor obtained by reading the mode page (i.e. via a MODE SENSE
256 command) is sent back when the mode page is written (i.e. via a MODE
257 SELECT command).
258
260 SCSI (draft) standards can be found at http://www.t10.org . The rele‐
261 vant documents are SPC-4 (mode pages common to all device types), SBC-2
262 (direct access devices [e.g. disks]), MMC-4 (CDs and DVDs) and SSC-2
263 (tapes).
264
266 Written by Eric Youngdale, Michael Weller, Douglas Gilbert, Kurt
267 Garloff, Thomas Steudten
268
270 scsiinfo version 1.0 was released by Eric Youngdale on 1st November
271 1993. The most recent version of scsiinfo is version 1.7 with the last
272 patches by Michael Weller. sginfo is derived from scsiinfo and uses the
273 sg interface to get around the 4 KB buffer limit in scsiinfo that
274 cramped the display of defect lists especially. sginfo was written by
275 Douglas Gilbert with patches from Kurt Garloff. This manpage corre‐
276 sponds with version 2.25 of sginfo.
277 This software is distributed under the GPL version 2. There is NO war‐
279 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
280 POSE.
281
283 scsiinfo(internet); sg_modes, sg_inq, sg_vpd (sg3_utils),
284 sdparm(sdparm)
285sg3_utils-1.26 March 2008 SGINFO(8)