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.
21 Four sets of values are maintained by a SCSI device for each mode page:
23 current (active), default (manufacturer's supplied values), saved (val‐
24 ues that are retained if the SCSI device is powered down), and change‐
25 able (mask indicating those values that can be changed). By default
26 when a mode page is displayed the current values are shown. This can be
27 overridden by "-M" (defaults), "-S" (saved) or "-m" (modifiable (i.e.
28 changeable)).
29 Many mode pages are decoded: for disks (see SBC-2), for CD/DVDs (see
31 MMC-2/3/4/5), for tapes (see SSC-2) and for enclosures (see SES-2).
32 Some mode pages common to all SCSI peripheral device types are defined
33 in SPC-4 (primary commands). A decoded mode page has its field names in
34 the first column and the corresponding value in the second column. A
35 "hex" mode page (and subpage) has its byte position in the first column
36 (in hex and starting at 0x2) and the corresponding hex value in the
37 second column. Decoded pages can be viewed with the '-t' option or with
38 a specific option (e.g. 'c' for the caching mode page). Naturally
39 decoded pages must be supplied by the DEVICE and recognised by this
40 program. If supported by the device, decoded pages may be modified. All
41 mode pages (and subpages) that the device supports can be viewed in hex
42 (and potentially modified) via the "-u" option
43 If no options are given that will cause mode page(s) or INQUIRY data to
45 be printed out, then a brief INQUIRY response is output. This includes
46 the vendor, product and revision level of the device.
47
49 -6 Perform 6 byte MODE SENSE and MODE SELECT commands; by default
50 the 10 byte variants are used.
51 -a Display some INQUIRY data and the unit serial number followed by
53 all mode pages reported by the device. It is similar to the '-t
54 0x3f' option. If the mode page is known then it is output in
55 decoded form otherwise it is output in hexadecimal.
56 -A Display some INQUIRY data and the unit serial number followed by
58 all mode pages and all mode subpages reported by the device. It
59 is similar to the '-t 0x3f,0xff' option. If a mode (sub)page is
60 known then it is output in decoded form otherwise it is output
61 in hexadecimal.
62 -c Access information in the Caching mode page.
64 -C Access information in the Control mode Page.
66 -d Display defect lists (default format: index).
68 -D Access information in the Disconnect-Reconnect mode page.
70 -e Access information in the Error Recovery mode page.
72 -E Access information in the Control Extension mode page.
74 -f Access information in the Format Device mode page.
76 -Farg Format of the defect lists:
78 -Flogical - logical block addresses (32 bit)
79 -Flba64 - logical block addresses (64 bit)
80 -Fphysical - physical blocks
81 -Findex - defect bytes from index
82 -Fhead - sort by head
83 Used in conjunction with "-d" or "-G". If a format is not given
84 "index" is assumed.
85 -g Access information in the Rigid Disk Drive Geometry mode page.
87 -G Display grown defect list (default format: index).
89 -i Display the response to a standard INQUIRY command.
91 -I Access the Informational Exceptions mode page.
93 -l List known SCSI devices on the system.
95 -n Access information in the Notch and Partition mode page.
97 -N Negate (i.e. stop) mode page changes being placed in the "saved"
99 page (by default changes go to the current and the saved page).
100 Only active when used together with '-R'.
101 -P Access information in the Power Condition mode page.
103 -r Display all raw (or primary) SCSI device names visible in the
105 /dev directory. Examples are /dev/sda, /dev/st1 and /dev/scd2.
106 Does not list sg device names so devices such as a SCSI enclo‐
107 sure which only have an sg device name are not listed.
108 -s Display information in the unit serial number page which is a
110 INQUIRY command variant.
111 -t PN[,SPN]
113 Display information from mode page number PN (and optionally sub
114 page number SPN) in decoded format (if known, otherwise in hex
115 form). PN is a mode page number in a decimal number from 0 to
116 63 inclusive. SPN is the mode subpage number and is assumed to
117 be 0 if not given. SPN is a decimal number from 1 to 255 inclu‐
118 sive. A page number of 63 returns all pages supported by the
119 device in ascending order except for page 0 which, if present,
120 is last. Page 0 is vendor specific and not necessarily in mode
121 page format. Alternatively hex values can be given for both
122 PNand SPN (both prefixed by '0x').
123 -t Trace commands (for debugging). When used once SCSI commands are
125 shown (in hex) and any errors from these SCSI commands are spelt
126 out (i.e. with a decoded and raw sense buffer). When used
127 twice, the additional data sent with mode select and the
128 response from mode sense are shown (in hex).
129 -u PN[,SPN]
131 Display information from mode page number PN (and optionally
132 SPN) in hex form. PNis a mode page number in a decimal number
133 from 0 to 63 inclusive. SPN is the mode subpage number and is
134 assumed to be 0 if not given. SPN is a decimal number from 1 to
135 255 inclusive. A page number of 63 returns all pages supported
136 by the device in ascending order except for page 0 which, if
137 present, is last. Page 0 is vendor specific and not necessarily
138 in mode page format. Alternatively hex values can be given for
139 both PN and SPN (both prefixed by '0x'). For example 63 and 0x3f
140 are equivalent.
141 -v
143 -V Access information in the Verify Error Recovery mode page.
145 -z do a single fetch for mode pages (over-estimating the expected
147 length of the returned response). The default action is to do a
148 double fetch, the first fetch is to find the response length
149 that could be returned. Devices that closely adhere to SCSI
150 standards should not require this option, some real world
151 devices do require it.
152
154 Only one of the following three options can be specified. None of
155 these three implies the current values are returned.
156 -m Display modifiable fields instead of current values
158 -M Display manufacturer's defaults instead of current values
160 -S Display saved defaults instead of current values
162 The following are advanced options, not generally suited for most
164 users:
165 -X Display output values in a list. Make them suitable for editing
167 and being given back to the '-R' (replace command).
168 \-R Replace parameters - best used with -X (expert use only)
170
172 Firstly you should know what you are doing before changing existing
173 parameters. Taking the control page as an example, first list it out
174 normally (e.g. "sginfo -C /dev/sda") and decide which parameter is to
175 be changed (note its position relative to the other lines output). Then
176 execute the same sginfo command with the "-X" option added; this will
177 output the parameter values in a single row in the same relative posi‐
178 tions as the previous command. Now execute "sginfo -CXR /dev/sda ..."
179 with the "..." replaced by the single row of values output by the pre‐
180 vious command, with the relevant parameter changed. Here is a simpli‐
181 fied example:
182 $ sginfo -C /dev/sda
184 Control mode page (0xa)
185 -----------------------
186 TST 0
187 D_SENSE 0
188 GLTSD 1
189 RLEC 0
190 [Actually the Control page has more parameters that shown above.] Next
192 output those parameters in single line form:
193 $ sginfo -CX /dev/sda
195 0 0 1 0
196 Let us assume that the GLTSD bit is to be cleared. The command that
198 will clear it is:
199 $ sginfo -CXR /dev/sda 0 0 0 0
201 The same number of parameters output by the "-CX" command needs to be
203 placed at the end of the "-CXR" command line (after the device name).
204 Now check that the change took effect:
205 $ sginfo -C /dev/sda
207 Control mode page (0xa)
208 -----------------------
209 TST 0
210 D_SENSE 0
211 GLTSD 0
212 RLEC 0
213 When a mode page is "replaced" the default action is to change both the
215 current page and the saved page. [For some reason versions of sginfo
216 and scsiinfo prior to 2.0 did not change the "saved" page.] To change
217 only the current mode page but not the corresponding saved page use the
218 "-N" option.
219
221 The "-aX" or "-AX" option generates output suitable for a script file.
222 Mode pages are output in list format (after the INQUIRY and serial num‐
223 ber) one page per line. To facilitate running the output as (part of) a
224 script file to assert chosen mode page values, each line is prefixed by
225 "sginfo -t PN[,SPN] -XR ". When such a script file is run, it will have
226 the effect of re-asserting the mode page values to what they were when
227 the "-aX" generated the output.
228 All mode pages (and subpages) supported by the device can be accessed
230 via the -t and -u options. To see all mode pages supported by the
231 device use "-u 63". [To see all mode pages and all subpages use "-u
232 63,255".] To list the control mode page in hex (mode page index in the
233 first column and the corresponding byte value in the second column) use
234 "-u 0xa". Mode pages (subpage code == 0) start at index position 2
235 while subpages start at index position 4. If the "-Xu ..." option is
236 used then a list a hex values each value prefixed by "@" is output.
237 Mode (sub)page values can then be modified with with the "-RXu ..."
238 option.
239
241 The SCSI MODE SENSE command yields block descriptors as well as a mode
242 page(s). This utility ignores block descriptors and does not display
243 them. The "disable block descriptor" switch (DBD) in the MODE SENSE
244 command is not set since some devices yield errors when it is set. When
245 mode page values are being changed (the "-R" option), the same block
246 descriptor obtained by reading the mode page (i.e. via a MODE SENSE
247 command) is sent back when the mode page is written (i.e. via a MODE
248 SELECT command).
249
251 SCSI (draft) standards can be found at http://www.t10.org . The rele‐
252 vant documents are SPC-4 (mode pages common to all device types), SBC-2
253 (direct access devices [e.g. disks]), MMC-4 (CDs and DVDs) and SSC-2
254 (tapes).
255
257 Written by Eric Youngdale, Michael Weller, Douglas Gilbert, Kurt
258 Garloff, Thomas Steudten
259
261 scsiinfo version 1.0 was released by Eric Youngdale on 1st November
262 1993. The most recent version of scsiinfo is version 1.7 with the last
263 patches by Michael Weller. sginfo is derived from scsiinfo and uses the
264 sg interface to get around the 4 KB buffer limit in scsiinfo that
265 cramped the display of defect lists especially. sginfo was written by
266 Douglas Gilbert with patches from Kurt Garloff. This manpage corre‐
267 sponds with version 2.01 of sginfo. It may be backported (or just
268 copied) soon to become scsiinfo 2.01 .
269 This software is distributed under the GPL version 2. There is NO war‐
271 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
272 POSE.
273
275 plscsi(internet), scsiinfo(internet), sg_modes(sg3_utils),
276 sg_inq(sg3_utils), sdparm(sdparm)
277 plscsi can send arbitrary (user supplied) SCSI commands; scsiinfo is
279 the predecessor of this utility; sg_modes is a low level MODE SENSE
280 based utility and sg_inq is specialized for the mandatory SCSI INQUIRY
281 command which contains a lot of information about advanced devices.
282 Users may find sdparm more convenient for getting and setting mode page
283 parameters.
284sg3_utils-1.23 December 2006 SGINFO(8)