1SG_REQUESTS(8) SG3_UTILS SG_REQUESTS(8)
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6 sg_requests - send one or more SCSI REQUEST SENSE commands
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9 sg_requests [--desc] [--help] [--hex] [--num=NUM] [--raw] [--status]
10 [--time] [--verbose] [--version] DEVICE
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13 Send REQUEST SENSE command to DEVICE and output the response which is
14 expected to be in sense data format. Both fixed and descriptor format
15 are supported.
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18 Arguments to long options are mandatory for short options as well.
19 -d, --desc
21 sets the DESC bit in the REQUEST SENSE SCSI cdb. The DEVICE
22 should return sense data in descriptor (rather than fixed) for‐
23 mat. This will only occur if the DEVICE recognizes descriptor
24 format (SPC-3 and later). If the device is pre SPC-3 then set‐
25 ting a bit in a reserved field may cause a check condition sta‐
26 tus with an illegal request sense key.
27 -h, --help
29 output the usage message then exit.
30 -H, --hex
32 output response in ASCII hexadecimal.
33 -n, --num=NUM
35 perform NUM SCSI REQUEST SENSE commands, stopping when either
36 NUM is reached or an error occurs. The default value for NUM is
37 1 .
38 -r, --raw
40 output response in binary (to stdout).
41 -s, --status
43 if the last REQUEST SENSE finished without error (from SCSI sta‐
44 tus or autosense) then the contents of the parameter data are
45 analysed as sense data and the exit status is set accordingly.
46 The default action (when this option is not given) is to ignore
47 the contents of the parameter data for the purposes of setting
48 the exit status. Some types of error set a sense key of "NO
49 SENSE" with non-zero information in the additional sense code
50 (e.g. the FAILURE PREDICTION THRESHOLD EXCEEDED group of codes);
51 this results in an exit status value of 10. If the sense key is
52 "NO SENSE" and both asc and ascq are zero then the exit status
53 is set to 0 . See the sg3_utils(8) man page for exit status val‐
54 ues.
55 -t, --time
57 time the SCSI REQUEST SENSE command(s) and calculate the average
58 number of operations per second.
59 -v, --verbose
61 increase the level of verbosity, (i.e. debug output). Addition‐
62 ally the response (if received) is output in ASCII-HEX. Use this
63 option multiple times for greater verbosity.
64 -V, --version
66 print the version string and then exit.
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69 In SCSI 1 and 2 the REQUEST SENSE command was very important for error
70 and warning processing in SCSI. The autosense capability rendered this
71 command almost superfluous.
72 However recent SCSI drafts (e.g. SPC-3 rev 23 and SBC-2 rev 16)
74 increase the utility of the REQUEST SENSE command. Idle and standby
75 power conditions can now be detected with this command; a progress
76 indication is given during FORMAT (when that command was started with
77 with IMMED=1 in its parameter header); and the Filemark, ILI and EOM
78 bits may be set (e.g. by a tape drive). Interestingly the sense key is
79 set to "no sense" while the asc/ascq code convey the information (e.g.
80 0x5e/0x4 "Standby condition activated by command").
81 The REQUEST SENSE command is not marked as mandatory in SPC-3 (i.e. for
83 all SCSI devices) but is marked as mandatory in SBC-2 (i.e. for disks),
84 SSC-3 (i.e. for tapes) and MMC-4 (i.e. for CD/DVD drives).
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87 The exit status of sg_requests is 0 when it is successful. Otherwise
88 see the sg3_utils(8) man page.
89
91 Written by Douglas Gilbert.
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94 Report bugs to <dgilbert at interlog dot com>.
95
97 Copyright © 2004-2007 Douglas Gilbert
98 This software is distributed under a FreeBSD license. There is NO war‐
99 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
100 POSE.
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103 sg3_utils
104sg3_utils-1.23 January 2007 SG_REQUESTS(8)