1SG3_UTILS(8) SG3_UTILS SG3_UTILS(8)
2
6 sg3_utils - a package of utilities for sending SCSI commands
7
9 sg_* [--dry-run] [--enumerate] [--help] [--hex] [--in=FN]
10 [--maxlen=LEN] [--raw] [--timeout=SECS] [--verbose] [--version]
11 [OTHER_OPTIONS] DEVICE
12
14 sg3_utils is a package of utilities that send SCSI commands to the
15 given DEVICE via a SCSI pass through interface provided by the host
16 operating system.
17 The names of all utilities start with "sg" and most start with "sg_"
19 often followed by the name, or a shortening of the name, of the SCSI
20 command that they send. For example the "sg_verify" utility sends the
21 SCSI VERIFY command. A mapping between SCSI commands and the sg3_utils
22 utilities that issue them is shown in the COVERAGE file. The sg_raw
23 utility can be used to send an arbitrary SCSI command (supplied on the
24 command line) to the given DEVICE.
25 sg_decode_sense can be used to decode SCSI sense data given on the com‐
27 mand line or in a file. sg_raw -vvv will output the T10 name of a given
28 SCSI CDB which is most often 16 bytes or less in length.
29 SCSI draft standards can be found at http://www.t10.org . The standards
31 themselves can be purchased from ANSI and other standards organiza‐
32 tions. A good overview of various SCSI standards can be seen in
33 http://www.t10.org/scsi-3.htm with the SCSI command sets in the upper
34 part of the diagram. The highest level (i.e. most abstract) document is
35 the SCSI Architecture Model (SAM) with SAM-5 being the most recent
36 standard (ANSI INCITS 515-2016) with the most recent draft being SAM-6
37 revision 4 . SCSI commands in common with all device types can be found
38 in SCSI Primary Commands (SPC) of which SPC-4 is the most recent stan‐
39 dard (ANSI INCITS 513-2015). The most recent SPC draft is SPC-5 revi‐
40 sion 19. Block device specific commands (e.g. as used by disks) are in
41 SBC, those for tape drives in SSC, those for SCSI enclosures in SES and
42 those for CD/DVD/BD drives in MMC.
43 It is becoming more common to control ATA disks with the SCSI command
45 set. This involves the translation of SCSI commands to their corre‐
46 sponding ATA equivalents (and that is an imperfect mapping in some
47 cases). The relevant standard is called SCSI to ATA Translation (SAT,
48 SAT-2 and SAT-3) are now standards at INCITS(ANSI) and ISO while SAT-4
49 is at the draft stage. The logic to perform the command translation is
50 often called a SAT Layer or SATL and may be within an operating system,
51 in host bus adapter firmware or in an external device (e.g. associated
52 with a SAS expander). See http://www.t10.org for more information.
53 There is some support for SCSI tape devices but not for their basic
55 operation. The reader is referred to the "mt" utility.
56 There are two generations of command line option usage. The newer util‐
58 ities (written since July 2004) use the getopt_long() function to parse
59 command line options. With that function, each option has two represen‐
60 tations: a short form (e.g. '-v') and a longer form (e.g. '--verbose').
61 If an argument is required then it follows a space (optionally) in the
62 short form and a "=" in the longer form (e.g. in the sg_verify utility
63 '-l 2a6h' and '--lba=2a6h' are equivalent). Note that with
64 getopt_long(), short form options can be elided, for example: '-all' is
65 equivalent to '-a -l -l'. The DEVICE argument may appear after,
66 between or prior to any options.
67 The older utilities, including as sg_inq, sg_logs, sg_modes, sg_opcode,
69 sg_rbuff, sg_readcap, sg_senddiag, sg_start and sg_turs had individual
70 command line processing code typically based on a single "-" followed
71 by one or more characters. If an argument is needed then it follows a
72 "=" ( e.g. '-p=1f' in sg_modes with its older interface). Various
73 options can be elided as long as it is not ambiguous (e.g. '-vv' to
74 increase the verbosity).
75 Over time the command line interface of these older utilities became
77 messy and overloaded with options. So in sg3_utils version 1.23 the
78 command line interface of these older utilities was altered to have
79 both a cleaner getopt_long() interface and their older interface for
80 backward compatibility. By default these older utilities use their
81 getopt_long() based interface. The getopt_long() is a GNU extension
82 (i.e. not yet POSIX certified) but more recent command line utilities
83 tend to use it. That can be overridden by defining the
84 SG3_UTILS_OLD_OPTS environment variable or using '-O' or '--old' as the
85 first command line option. The man pages of the older utilities docu‐
86 ments the details.
87 Several sg3_utils utilities are based on the Unix dd command (e.g.
89 sg_dd) and permit copying data at the level of SCSI READ and WRITE com‐
90 mands. sg_dd is tightly bound to Linux and hence is not ported to other
91 OSes. A more generic utility (than sg_dd) called ddpt in a package of
92 the same name has been ported to other OSes.
93
95 The SG3_UTILS_OLD_OPTS environment variable is explained in the previ‐
96 ous section. It is only for backward compatibility of the command line
97 options for older utilities.
98 The SG3_UTILS_DSENSE environment variable may be set to a number. If
100 that number is non-zero then descriptor sense is set in the SNTL (the
101 small SCSI to NVMe Translation Layer within the underlying library).
102 Several utilities have their own environment variable setting (e.g.
104 sg_persist has SG_PERSIST_IN_RDONLY). See individual utility man pages
105 for more information.
106
108 Most disk block devices have names like /dev/sda, /dev/sdb, /dev/sdc,
109 etc. SCSI disks in Linux have always had names like that but in recent
110 Linux kernels it has become more common for many other disks (including
111 SATA disks and USB storage devices) to be named like that. Partitions
112 within a disk are specified by a number appended to the device name,
113 starting at 1 (e.g. /dev/sda1 ).
114 Tape drives are named /dev/st<num> or /dev/nst<num> where <num> starts
116 at zero. Additionally one letter from this list: "lma" may be appended
117 to the name. CD, DVD and BD readers (and writers) are named
118 /dev/sr<num> where <num> start at zero. There are less used SCSI device
119 type names, the dmesg and the lsscsi commands may help to find if any
120 are attached to a running system.
121 There is also a SCSI device driver which offers alternate generic
123 access to SCSI devices. It uses names of the form /dev/sg<num> where
124 <num> starts at zero. The "lsscsi -g" command may be useful in finding
125 these and which generic name corresponds to a device type name (e.g.
126 /dev/sg2 may correspond to /dev/sda). In the lk 2.6 series a block SCSI
127 generic driver was introduced and its names are of the form
128 /dev/bsg/<h:c:t:l> where h, c, t and l are numbers. Again see the lss‐
129 csi command to find the correspondence between that SCSI tuple (i.e.
130 <h:c:t:l>) and alternate device names.
131 Prior to the Linux kernel 2.6 series these utilities could only use
133 generic device names (e.g. /dev/sg1 ). In almost all cases in the Linux
134 kernel 2.6 series, any device name can be used by these utilities.
135 Very little has changed in Linux device naming in the Linux kernel 3
137 and 4 series.
138
140 Storage and related devices can have several device names in Windows.
141 Probably the most common in the volume name (e.g. "D:"). There are also
142 a "class" device names such as "PhysicalDrive<n>", "CDROM<n>" and
143 "TAPE<n>". <n> is an integer starting at 0 allocated in ascending order
144 as devices are discovered (and sometimes rediscovered).
145 Some storage devices have a SCSI lower level device name which starts
147 with a SCSI (pseudo) adapter name of the form "SCSI<n>:". To this is
148 added sub-addressing in the form of a "bus" number, a "target" identi‐
149 fier and a LUN (Logical Unit Number). The "bus" number is also known as
150 a "PathId". These are assembled to form a device name of the form:
151 "SCSI<n>:<bus>,<target>,<lun>". The trailing ",<lun>" may be omitted in
152 which case a LUN of zero is assumed. This lower level device name can‐
153 not often be used directly since Windows blocks attempts to use it if a
154 class driver has "claimed" the device. There are SCSI device types
155 (e.g. Automation/Drive interface type) for which there is no class
156 driver. At least two transports ("bus types" in Windows jargon): USB
157 and IEEE 1394 do not have a "scsi" device names of this form.
158 In keeping with DOS file system conventions, the various device names
160 can be given in upper, lower or mixed case. Since "PhysicalDrive<n>" is
161 tedious to write, a shortened form of "PD<n>" is permitted by all util‐
162 ities in this package.
163 A single device (e.g. a disk) can have many device names. For example:
165 "PD0" can also be "C:", "D:" and "SCSI0:0,1,0". The two volume names
166 reflect that the disk has two partitions on it. Disk partitions that
167 are not recognized by Windows are not usually given a volume name. How‐
168 ever Vista does show a volume name for a disk which has no partitions
169 recognized by it and when selected invites the user to format it (which
170 may be rather unfriendly to other OSes).
171 These utilities assume a given device name is in the Win32 device
173 namespace. To make that explicit "\\.\" can be prepended to the device
174 names mentioned in this section. Beware that backslash is an escape
175 character in Unix like shells and the C programming language. In a
176 shell like Msys (from MinGW) each backslash may need to be typed twice.
177 The sg_scan utility within this package lists out Windows device names
179 in a form that is suitable for other utilities in this package to use.
180
182 SCSI disks have block names of the form /dev/da<num> where <num> is an
183 integer starting at zero. The "da" is replaced by "sa" for SCSI tape
184 drives and "cd" for SCSI CD/DVD/BD drives. Each SCSI device has a cor‐
185 responding pass-through device name of the form /dev/pass<num> where
186 <num> is an integer starting at zero. The "camcontrol devlist" command
187 may be useful for finding out which SCSI device names are available and
188 the correspondence between class and pass-through names.
189
191 SCSI device names below the /dev directory have a form like: c5t4d3s2
192 where the number following "c" is the controller (HBA) number, the num‐
193 ber following "t" is the target number (from the SCSI parallel inter‐
194 face days) and the number following "d" is the LUN. Following the "s"
195 is the slice number which is related to a partition and by convention
196 "s2" is the whole disk.
197 OpenSolaris also has a c5t4d3p2 form where the number following the "p"
199 is the partition number apart from "p0" which is the whole disk. So a
200 whole disk may be referred to as either c5t4d3, c5t4d3s2 or c5t4d3p0 .
201 And these device names are duplicated in the /dev/dsk and /dev/rdsk
203 directories. The former is the block device name and the latter is for
204 "raw" (or char device) access which is what sg3_utils needs. So in
205 OpenSolaris something of the form 'sg_inq /dev/rdsk/c5t4d3p0' should
206 work. If it doesn't work then add a '-vvv' option for more debug
207 information. Trying this form 'sg_inq /dev/dsk/c5t4d3p0' (note "rdsk"
208 changed to "dsk") will result in an "inappropriate ioctl for device"
209 error.
210 The device names within the /dev directory are typically symbolic links
212 to much longer topological names in the /device directory. In Solaris
213 cd/dvd/bd drives seem to be treated as disks and so are found in the
214 /dev/rdsk directory. Tape drives appear in the /dev/rmt directory.
215 There is also a sgen (SCSI generic) driver which by default does not
217 attach to any device. See the /kernel/drv/sgen.conf file to control
218 what is attached. Any attached device will have a device name of the
219 form /dev/scsi/c5t4d3 .
220 Listing available SCSI devices in Solaris seems to be a challenge. "Use
222 the 'format' command" advice works but seems a very dangerous way to
223 list devices. [It does prompt again before doing any damage.] 'devfsadm
224 -Cv' cleans out the clutter in the /dev/rdsk directory, only leaving
225 what is "live". The "cfgadm -v" command looks promising.
226
228 NVMe (or NVM Express) is a relatively new storage transport and command
229 set. The level of abstraction of the NVMe command set is somewhat lower
230 the SCSI command sets, closer to the level of abstraction of ATA (and
231 SATA) command sets. NVMe claims to be designed with flash and modern
232 "solid state" storage in mind, something unheard of when SCSI was orig‐
233 inally developed in the 1980s.
234 The SCSI command sets' advantage is the length of time they have been
236 in place and the existing tools (like these) to support it. Plus SCSI
237 command sets level of abstraction is both and advantage and disadvan‐
238 tage. Recently the NVME-MI (Management Interface) designers decide to
239 use the SCSI Enclosure Services (SES-3) standard "as is" with the addi‐
240 tion of two tunnelling NVME-MI commands: SES Send and SES Receive. This
241 means after the OS interface differences are taken into account, the
242 sg_ses, sg_ses_microcode and sg_senddiag utilities can be used on a
243 NVMe device that supports a newer version of NVME-MI.
244 The NVME-MI SES Send and SES Receive commands correspond to the SCSI
246 SEND DIAGNOSTIC and RECEIVE DIAGNOSTIC RESULTS commands respectively.
247 There are however a few other commands that need to be translated, the
248 most important of which is the SCSI INQUIRY command to the NVMe Iden‐
249 tify controller/namespace. Version 1.43 of these utilities contain a
250 small SNTL (SCSI to NVMe Translation Layer) to take care of these
251 details.
252 As a side effect of this "juggling" if the sg_inq utility is used
254 (without the --page= option) on a NVMe DEVICE then the actual NVMe
255 Identifier (controller and possibly namespace) responses are decoded
256 and output. However if 'sg_inq --page=sinq <device>' is given for the
257 same DEVICE then parts of the NVMe Identify controller and namespace
258 response are translated to a SCSI standard INQUIRY response which is
259 then decoded and output.
260 Apart from the special case with the sg_inq, all other utilities in the
262 package assume they are talking to a SCSI device and decode any
263 response accordingly. One easy way for users to see the underlying
264 device is a NVMe device is the standard INQUIRY response Vendor Identi‐
265 fication field of "NVMe " (an 8 character long string with 4 spaces
266 to the right).
267
269 To aid scripts that call these utilities, the exit status is set to
270 indicate success (0) or failure (1 or more). Note that some of the
271 lower values correspond to the SCSI sense key values.
272 The exit status values listed below can be given to the sg_decode_sense
274 utility (which is found in this package) as follows:
275 sg_decode_sense --err=<exit_status>
276 and a short explanatory string will be output to stdout.
277 The exit status values are:
279 0 success. Also used for some utilities that wish to return a
281 boolean value for the "true" case (and that no error has
282 occurred). The false case is conveyed by exit status 36.
283 1 syntax error. Either illegal command line options, options with
285 bad arguments or a combination of options that is not permitted.
286 2 the DEVICE reports that it is not ready for the operation
288 requested. The DEVICE may be in the process of becoming ready
289 (e.g. spinning up but not at speed) so the utility may work
290 after a wait. In Linux the DEVICE may be temporarily blocked
291 while error recovery is taking place.
292 3 the DEVICE reports a medium or hardware error (or a blank
294 check). For example an attempt to read a corrupted block on a
295 disk will yield this value.
296 5 the DEVICE reports an "illegal request" with an additional sense
298 code other than "invalid command operation code". This is often
299 a supported command with a field set requesting an unsupported
300 capability. For commands that require a "service action" field
301 this value can indicate that the command with that service
302 action value is not supported.
303 6 the DEVICE reports a "unit attention" condition. This usually
305 indicates that something unrelated to the requested command has
306 occurred (e.g. a device reset) potentially before the current
307 SCSI command was sent. The requested command has not been exe‐
308 cuted by the device. Note that unit attention conditions are
309 usually only reported once by a device.
310 7 the DEVICE reports a "data protect" sense key. This implies some
312 mechanism has blocked writes (or possibly all access to the
313 media).
314 9 the DEVICE reports an illegal request with an additional sense
316 code of "invalid command operation code" which means that it
317 doesn't support the requested command.
318 10 the DEVICE reports a "copy aborted". This implies another com‐
320 mand or device problem has stopped a copy operation. The
321 EXTENDED COPY family of commands (including WRITE USING TOKEN)
322 may return this sense key.
323 11 the DEVICE reports an aborted command. In some cases aborted
325 commands can be retried immediately (e.g. if the transport
326 aborted the command due to congestion).
327 14 the DEVICE reports a miscompare sense key. VERIFY and COMPARE
329 AND WRITE commands may report this.
330 15 the utility is unable to open, close or use the given DEVICE or
332 some other file. The given file name could be incorrect or there
333 may be permission problems. Adding the '-v' option may give more
334 information.
335 17 a SCSI "Illegal request" sense code received with a flag indi‐
337 cating the Info field is valid. This is often a LBA but its
338 meaning is command specific.
339 18 the DEVICE reports a medium or hardware error (or a blank check)
341 with a flag indicating the Info field is valid. This is often a
342 LBA (of the first encountered error) but its meaning is command
343 specific.
344 20 the DEVICE reports it has a check condition but "no sense" and
346 non-zero information in its additional sense codes. Some polling
347 commands (e.g. REQUEST SENSE) can receive this response. There
348 may be useful information in the sense data such as a progress
349 indication.
350 21 the DEVICE reports a "recovered error". The requested command
352 was successful. Most likely a utility will report a recovered
353 error to stderr and continue, probably leaving the utility with
354 an exit status of 0 .
355 22 the DEVICE reports that the current command or its parameters
357 imply a logical block address (LBA) that is out of range. This
358 happens surprisingly often when trying to access the last block
359 on a storage device; either a classic "off by one" logic error
360 or a misreading of the response from READ CAPACITY(10 or 16) in
361 which the address of the last block rather than the number of
362 blocks on the DEVICE is returned. Since LBAs are origin zero
363 they range from 0 to n-1 where n is the number of blocks on the
364 DEVICE, so the LBA of the last block is one less than the total
365 number of blocks.
366 24 the DEVICE reports a SCSI status of "reservation conflict". This
368 means access to the DEVICE with the current command has been
369 blocked because another machine (HBA or SCSI "initiator") holds
370 a reservation on this DEVICE. On modern SCSI systems this is
371 related to the use of the PERSISTENT RESERVATION family of com‐
372 mands.
373 25 the DEVICE reports a SCSI status of "condition met". Currently
375 only the PRE-FETCH command (see SBC-4) yields this status.
376 26 the DEVICE reports a SCSI status of "busy". SAM-6 defines this
378 status as the logical unit is temporarily unable to process a
379 command. It is recommended to re-issue the command.
380 27 the DEVICE reports a SCSI status of "task set full".
382 28 the DEVICE reports a SCSI status of "ACA active". ACA is "auto
384 contingent allegiance" and is seldom used.
385 29 the DEVICE reports a SCSI status of "task aborted". SAM-5 says:
387 "This status shall be returned if a command is aborted by a com‐
388 mand or task management function on another I_T nexus and the
389 Control mode page TAS bit is set to one".
390 31 error involving two or more command line options. They may be
392 contradicting, select an unsupported mode, or a required option
393 (given the context) is missing.
394 32 there is a logic error in the utility. It corresponds to code
396 comments like "shouldn't/can't get here". Perhaps the author
397 should be informed.
398 33 the command sent to DEVICE has timed out.
400 36 no error has occurred plus the utility wants to convey a boolean
402 value of false. The corresponding true value is conveyed by a 0
403 exit status.
404 40 the command sent to DEVICE has received an "aborted command"
406 sense key with an additional sense code of 0x10. This group is
407 related to problems with protection information (PI or DIF). For
408 example this error may occur when reading a block on a drive
409 that has never been written (or is unmapped) if that drive was
410 formatted with type 1, 2 or 3 protection.
411 41 the command sent to DEVICE has received an "aborted command"
413 sense key with an additional sense code of 0x10 (as with error
414 code) plus a flag indicating the Info field is valid.
415 48 this is an internal message indicating a NVMe status field (SF)
417 is other than zero after a command has been executed (i.e. some‐
418 thing went wrong). Work in this area is currently experimental.
419 49 low level driver reports a response's residual count (i.e. num‐
421 ber of bytes actually received by HBA is 'requested_bytes -
422 residual_count') that is
423 50 OS system calls that fail often return a small integer number to
425 help. In Unix these are called "errno" values where 0 implies no
426 error. These error codes set aside 51 to 96 for mapping these
427 errno values but that may not be sufficient. Higher errno values
428 that cannot be mapped are all mapped to this value (i.e. 50).
429 Note that an errno value of 0 is mapped to error code 0.
430 50 + <os_error_number>
432 OS system calls that fail often return a small integer number to
433 help indicate what the error is. For example in Unix the inabil‐
434 ity of a system call to allocate memory returns (in 'errno')
435 ENOMEM which often is associated with the integer 12. So 62
436 (i.e. '50 + 12') may be returned by a utility in this case. It
437 is also possible that a utility in this package reports
438 50+ENOMEM when it can't allocate memory, not necessarily from an
439 OS system call. In recent versions of Linux the file showing the
440 mapping between symbolic constants (e.g. ENOMEM) and the corre‐
441 sponding integer is in the kernel source code file:
442 include/uapi/asm-generic/errno-base.h
443 Note that errno values that are greater than or equal to 47 can‐
444 not fit in range provided. Instead they are all mapped to 50 as
445 discussed in the previous entry.
446 97 a SCSI command response failed sanity checks.
448 98 the DEVICE reports it has a check condition but the error
450 doesn't fit into any of the above categories.
451 99 any errors that can't be categorized into values 1 to 98 may
453 yield this value. This includes transport and operating system
454 errors after the command has been sent to the device.
455 100-125
457 these error codes are used by the ddpt utility which uses the
458 sg3_utils library. They are mainly specialized error codes asso‐
459 ciated with offloaded copies.
460 126 the utility was found but could not be executed. That might
462 occur if the executable does not have execute permissions.
463 127 This is the exit status for utility not found. That might occur
465 when a script calls a utility in this package but the PATH envi‐
466 ronment variable has not been properly set up, so the script
467 cannot find the executable.
468 128 + <signum>
470 If a signal kills a utility then the exit status is 128 plus the
471 signal number. For example if a segmentation fault occurs then a
472 utility is typically killed by SIGSEGV which according to 'man 7
473 signal' has an associated signal number of 11; so the exit sta‐
474 tus will be 139 .
475 255 the utility tried to yield an exit status of 255 or larger. That
477 should not happen; given here for completeness.
478 Most of the error conditions reported above will be repeatable (an
480 example of one that is not is "unit attention") so the utility can be
481 run again with the '-v' option (or several) to obtain more information.
482
484 Arguments to long options are mandatory for short options as well. In
485 the short form an argument to an option uses zero or more spaces as a
486 separator (i.e. the short form does not use "=" as a separator).
487 If an option takes a numeric argument then that argument is assumed to
489 be decimal unless otherwise indicated (e.g. with a leading "0x", a
490 trailing "h" or as noted in the usage message).
491 Some options are used uniformly in most of the utilities in this pack‐
493 age. Those options are listed below. Note that there are some excep‐
494 tions.
495 -d, --dry-run
497 utilities that can cause lots of user data to be lost or over‐
498 written sometimes have a --dry-run option. Device modifying
499 actions are typically bypassed (or skipped) to implement a pol‐
500 icy of "do no harm". This allows complex command line invoca‐
501 tions to be tested before the action required (e.g. format a
502 disk) is performed. The --dry-run option has become a common
503 feature of many command line utilities (e.g. the Unix 'patch'
504 command), not just those from this package.
505 Note that most hyphenated option names in this package also can
506 be given with an underscore rather than a hyphen (e.g.
507 --dry_run).
508 -e, --enumerate
510 some utilities (e.g. sg_ses and sg_vpd) store a lot of informa‐
511 tion in internal tables. This option will output that informa‐
512 tion in some readable form (e.g. sorted by an acronym or by page
513 number) then exit. Note that with this option DEVICE is ignored
514 (as are most other options) and no SCSI IO takes place, so the
515 invoker does not need any elevated permissions.
516 -h, -?, --help
518 output the usage message then exit. In a few older utilities the
519 '-h' option requests hexadecimal output. In these cases the '-?'
520 option will output the usage message then exit.
521 -H, --hex
523 for SCSI commands that yield a non-trivial response, print out
524 that response in ASCII hexadecimal. To produce hexadecimal that
525 can be parsed by other utilities (e.g. without a relative
526 address to the left and without trailing ASCII) use this option
527 three or four times.
528 -i, --in=FN
530 many SCSI commands fetch a significant amount of data (returned
531 in the data-in buffer) which several of these utilities decode
532 (e.g. sg_vpd and sg_logs). To separate the two steps of fetching
533 the data from a SCSI device and then decoding it, this option
534 has been added. The first step (fetching the data) can be done
535 using the --hex or --raw option and redirecting the command line
536 output to a file (often done with ">" in Unix based operating
537 systems). The difference between --hex and --raw is that the
538 former produces output in ASCII hexadecimal while --raw produces
539 its output in "raw" binary.
540 The second step (i.e. decoding the SCSI response data now held
541 in a file) can be done using this --in=FN option where the file
542 name is FN. If "-" is used for FN then stdin is assumed, again
543 this allows for command line redirection (or piping). That file
544 (or stdin) is assumed to contain ASCII hexadecimal unless the
545 --raw option is also given in which case it is assumed to be
546 binary. Notice that the meaning of the --raw option is "flipped"
547 when used with --in=FN to act on the input, typically it acts on
548 the output data.
549 Since the structure of the data returned by SCSI commands varies
550 considerably then the usage information or the manpage of the
551 utility being used should be checked. In some cases --hex may
552 need to be used multiple times (and is more conveniently given
553 as '-HH' or '-HHH). In other cases the name of this option is
554 --inhex=FN.
555 -m, --maxlen=LEN
557 several important SCSI commands (e.g. INQUIRY and MODE SENSE)
558 have response lengths that vary depending on many factors, only
559 some of which these utilities take into account. The maximum
560 response length is typically specified in the 'allocation
561 length' field of the cdb. In the absence of this option, several
562 utilities use a default allocation length (sometimes recommended
563 in the SCSI draft standards) or a "double fetch" strategy. See
564 sg_logs(8) for its description of a "double fetch" strategy.
565 These techniques are imperfect and in the presence of faulty
566 SCSI targets can cause problems (e.g. some USB mass storage
567 devices freeze if they receive an INQUIRY allocation length
568 other than 36). Also use of this option disables any "double
569 fetch" strategy that may have otherwise been used.
570 -r, --raw
572 for SCSI commands that yield a non-trivial response, output that
573 response in binary to stdout. If any error messages or warning
574 are produced they are usually sent to stderr so as to not inter‐
575 fere with the output from this option.
576 Some utilities that consume data to send to the DEVICE along
577 with the SCSI command, use this option. Alternatively the
578 --in=FN option causes DEVICE to be ignored and the response data
579 (to be decoded) fetched from a file named FN. In these cases
580 this option may indicate that binary data can be read from stdin
581 or from a nominated file (e.g. FN).
582 -t, --timeout=SECS
584 utilities that issue potentially long-running SCSI commands
585 often have a --timeout=SECS option. This typically instructs the
586 operating system to abort the SCSI command in question once the
587 timeout expires. Aborting SCSI commands is typically a messy
588 business and in the case of format like commands may leave the
589 device in a "format corrupt" state requiring another long-run‐
590 ning re-initialization command to be sent. The argument, SECS,
591 is usually in seconds and the short form of the option may be
592 something other than -t since the timeout option was typically
593 added later as storage devices grew in size and initialization
594 commands took longer. Since many utilities had relatively long
595 internal command timeouts before this option was introduced, the
596 actual command timeout given to the operating systems is the
597 higher of the internal timeout and SECS.
598 Many long running SCSI commands have an IMMED bit which causes
599 the command to finish relatively quickly but the initialization
600 process to continue. In such cases the REQUEST SENSE command can
601 be used to monitor progress with its progress indication field
602 (see the sg_requests and sg_turs utilities). Utilities that
603 send such SCSI command either have an --immed option or a --wait
604 option which is the logical inverse of the "immediate" action.
605 -v, --verbose
607 increase the level of verbosity, (i.e. debug output). Can be
608 used multiple times to further increase verbosity. The addi‐
609 tional output caused by this option is almost always sent to
610 stderr.
611 -V, --version
613 print the version string and then exit. Each utility has its own
614 version number and date of last code change.
615
617 Many utilities have command line options that take numeric arguments.
618 These numeric arguments can be large values (e.g. a logical block
619 address (LBA) on a disk) and can be inconvenient to enter in the
620 default decimal representation. So various other representations are
621 permitted.
622 Multiplicative suffixes are accepted. They are one, two or three letter
624 strings appended directly after the number to which they apply:
625 c C *1
627 w W *2
628 b B *512
629 k K KiB *1024
630 KB kB *1000
631 m M MiB *1048576
632 MB mB *1000000
633 g G GiB *(2^30)
634 GB gB *(10^9)
635 t T TiB *(2^40)
636 TB *(10^12)
637 p P PiB *(2^50)
638 PB *(10^15)
639 An example is "2k" for 2048. The large tera and peta suffixes are only
641 available for numeric arguments that might require 64 bits to represent
642 internally.
643 A suffix of the form "x<n>" multiplies the leading number by <n>. An
645 example is "2x33" for "66". The leading number cannot be "0" (zero) as
646 that would be interpreted as a hexadecimal number (see below).
647 These multiplicative suffixes are compatible with GNU's dd command
649 (since 2002) which claims compliance with SI and with IEC 60027-2.
650 Alternatively numerical arguments can be given in hexadecimal. There
652 are two syntaxes. The number can be preceded by either "0x" or "0X" as
653 found in the C programming language. The second hexadecimal representa‐
654 tion is a trailing "h" or "H" as found in (storage) standards. When hex
655 numbers are given, multipliers cannot be used. For example the decimal
656 value "256" can be given as "0x100" or "100h".
657
659 There are two standardized methods for downloading microcode (i.e.
660 device firmware) to a SCSI device. The more general way is with the
661 SCSI WRITE BUFFER command, see the sg_write_buffer utility. SCSI enclo‐
662 sures have their own method based on the Download microcode con‐
663 trol/status diagnostic page, see the sg_ses_microcode utility.
664
666 There are several bash shell scripts in the 'scripts' subdirectory that
667 invoke compiled utilities (e.g. sg_readcap). Several of the scripts
668 start with 'scsi_' rather than 'sg_'. One purpose of these scripts is
669 to call the same utility (e.g. sg_readcap) on multiple devices. Most of
670 the basic compiled utilities only allow one device as an argument. Some
671 distributions install these scripts in a more visible directory (e.g.
672 /usr/bin). Some of these scripts have man page entries. See the README
673 file in the 'scripts' subdirectory.
674 There is some example C code plus examples of complex invocations in
676 the 'examples' subdirectory. There is also a README file. The example C
677 may be a simpler example of how to use a SCSI pass-through in Linux
678 than the main utilities (found in the 'src' subdirectory). This is due
679 to the fewer abstraction layers (e.g. they don't worry the MinGW in
680 Windows may open a file in text rather than binary mode).
681 Some utilities that the author has found useful have been placed in the
683 'utils' subdirectory.
684
686 There is a web page discussing this package at
687 http://sg.danny.cz/sg/sg3_utils.html . The device naming used by this
688 package on various operating systems is discussed at:
689 http://sg.danny.cz/sg/device_name.html . There is a git code mirror at
690 https://github.com/hreinecke/sg3_utils . The principle code repository
691 uses subversion and is on the author's equipment. The author keeps
692 track of this via the subversion revision number which is an ascending
693 integer (currently at 774 for this package). The github mirror gets
694 updated periodically from the author's repository. Depending on the
695 time of update, the above Downloads section at sg.danny.cz may be more
696 up to date than the github mirror.
697
699 Written by Douglas Gilbert. Some utilities have been contributed, see
700 the CREDITS file and individual source files (in the 'src' directory).
701
703 Report bugs to <dgilbert at interlog dot com>.
704
706 Copyright © 1999-2018 Douglas Gilbert
707 Some utilities are distributed under a GPL version 2 license while oth‐
708 ers, usually more recent ones, are under a FreeBSD license. The files
709 that are common to almost all utilities and thus contain the most reus‐
710 able code, namely sg_lib.[hc], sg_cmds_basic.[hc] and
711 sg_cmds_extra.[hc] are under a FreeBSD license. There is NO warranty;
712 not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
713
715 sdparm(sdparm), ddpt(ddpt), lsscsi(lsscsi), dmesg(1), mt(1)
716sg3_utils-1.44 September 2018 SG3_UTILS(8)