sdparm  1.12
About: sdparm let you access SCSI modes pages, read VPD pages, send simple SCSI commands (similar functionality for SCSI disks like "hdparm" for ATA disks).
  Fossies Dox: sdparm-1.12.tgz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

sdparm Documentation

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sdparm is a utility for listing and potentially changing SCSI disk
parameters. More generally it can be used on any device that uses a SCSI
command set. Apart form SCSI disks, examples of devices that use SCSI command
sets are ATAPI CD/DVD drives, SCSI and ATAPI tape drives and SCSI enclosures.

This utility was originally written for Linux. It has been ported to FreeBSD,
Solaris, Tru64, and Windows.

Relationship to sg3_utils
Starting with sdparm version 1.02 this package shares code with sg3_utils
(start with sg3_utils version 1.25). With the subversion revision control
system this is done by having sdparm's "include/" and "lib/" subdirectories
pointing to the correspondingly named directories in the sg3_utils package
using the "svn:externals" property. These two "external" directories include
more files than sdparm uses. The excess files include "lib/" and
"lib/". The "" in sdparm's "src/" directory does the
main part of the build. When the tarball is generated for this utility,
various files are "exported" out of the subversion repository and
"svn:externals" redirection is no longer visible (but the unused files are

The sdparm executable may or may not be built depending on the libsgutils
(shared) library. Currently the ./configure rules are looking for a library
called libsgutils2.a or . In Debian those libraries are found
only in the libsgutils2-dev package, not the libsgutils2 package. If one of
those libraries is detected then sdparm will be built depending on libsgutils
(check 'ldd sdparm'). If neither of those libraries is detected at build time,
then the sdparm executable built will compile and link the relevant code from
its "include/" and "lib/" subdirectories.

The utility outputs a usage message when the "--help" (or '-h' or '-?') option
is given. Many syntax errors also result in the usage message being printed.
There is also a man page which is in section 8 (administration and privileged
commands). It can be accessed with "man sdparm" once this package is
installed. Prior to installation the man page can be viewed from this
package's main directory with "man doc/sdparm.8".

There is a web page about this utility at .

Build infrastructure
This package uses the automake and autoconf tools. The generating files
(scripts) are,, src/ and .
The script only needs to be executed if one of the other generating
files in the above list is changed.

There is a rpm "spec" file in the main directory: sdparm.spec . There are
Debian build files in the "debian" directory and a script called in the main directory. If fails due to
compatibility level. Amongst other things debian builds are sensitive to
the value in the debian/compat file. If it contains "7" then it works on
lenny and gives warning on squeeze (but fails on the earlier etch).

The ./configure script supports these extra options:
  - '--disable-libsgutils' stops the build using the libsgutils library
    if it is found. Instead the copy of those files found under the
    include and lib directories is used.
  - '--disable-linuxbsg' drops Linux bsg driver support. This is only
    for testing and should no longer be necessary.
  - '--disable-scsistrings' excludes the asc/ascq and command name strings
    (defined by SCSI/T10) in an attempt to reduce the size of executables.

At the request of some Linux distributions, this package will attempt to
use the libsgutils library (name varies between distributions) at build time.
If that library is old then the link at the end of build can fail. One way
to sidestep that problem is by using './configure --disable-libsgutils'.
Another way is to remove the "dev" version of the libsgutils library package
(e.g. 'libsgutils2-dev' on a Debian based distribution).

This utility is covered by a FreeBSD license. The intention of the author
is that both open source and commercial entities can re-use this code.
Naturally credit and improvement/bug feedback are encouraged. The part
of this code that others may be able to re-use is the information in
the tables in sdparm_data.c , sg_lib.c and sg_lib_data.c . This is
information garnered from SCSI drafts and standards at
(plus some information from the ATA drafts and standards at ). Vendor specific mode page information is found in the
sdparm_data_vendor.c file and is derived from vendor product manuals.

Generic information about building this package (i.e. './configure ; make;
make install') can be found in the INSTALL file. The contents of the COPYING
file is a FreeBSD license (rather than the GPL v2 found in the usual

Linux port
The utility can be used on any device that supports the SG_IO ioctl. In
the Linux 2.4 series that is only the scsi generic (i.e. /dev/sg* )
device nodes. In the Linux 2.6 series the supported device nodes has
expanded to all other SCSI device nodes (e.g. /dev/sd* and /dev/sr*)
plus block devices such as /dev/hdc when the associated device is a
DVD drive. The man page and web page
examples use Linux device node names.

FreeBSD port
Virtually all of sdparm's features work with FreeBSD. SCSI commands are
routed through the CAM pass through interface. The author tested sdparm
with FreeBSD version 5.3 and found SCSI disks worked with the "da" device
(e.g. 'sdparm  /dev/da0'). SCSI tape drives can be accessed via the "sa"
device via /dev nodes starting with "esa", "nsa" and "sa". To access cd/dvd
drives, the kernel needs to be build with the "atapicam" device after which
access is via the "cd" device. Other SCSI devices are "ses" (for enclosure
services), "ch" (media changer (for tapes)), and "pr" for processor device
type (e.g. SAF-TE devices). All these device may also be accessed via
the "pass" device. To see the mapping between the "pass" device name and
the corresponding higher level device node try "camcontrol devlist".

The traditional './configure ; make ; make install' sequence from the
top level of the unpacked tarball will work on FreeBSD. But the man pages
will be placed under the /usr/local/share/man directory which unfortunately
is not on the standard manpath. One solution is to add this path by
creating a file with a name like local_share.conf in the
/usr/local/etc/man.d/ directory and placing this line in it:
    MANPATH /usr/local/share/man

FreeBSD 9.0 has a "ports" entry for sdparm under the
/usr/ports/sysutils directory. It points to version 1.06 of sdparm.
It could be used as a template to point to more recent versions.

sdparm can be built into a Debian package for kFreeBSD using the
./ script in the top level directory. This has been tested
with Debian 6.0 release.

Solaris port
The uscsi pass-through mechanism is used and is only available on SCSI
devices. There seems to be no corresponding ATA pass through and recent
SATA disks do not seem to have a SAT layer in front of them (within
Solaris). If SAT is present (perhaps externally or within a HBA) then that
would allow SATA disks to accept SCSI commands including the SCSI ATA PASS
THROUGH commands.

SCSI device names below the '/dev' directory have a form like: c5t4d3s2
where the number following "c" is the controller (HBA) number, the number
following "t" is the target number (from the SCSI parallel interface days)
and the number following "d" is the LUN. Following the "s" is the slice
number which is related to a partition and by convention "s2" is the whole

OpenSolaris also has a c5t4d3p2 form where the number following the "p" is
the partition number apart from "p0" which is the whole disk. So a whole
disk may be referred to as either:
  - c5t4d3
  - c5t4d3s2
  - c5t4d3p0

And these device names are duplicated in the /dev/dsk and /dev/rdsk
directories. The former is the block device name and the latter is for "raw"
(or char device) access which is what sdparm needs. So in openSolaris
something of the form:
   sdparm /dev/rdsk/c5t4d3p0
should work. If it doesn't add a '-vvv' option. If that is attempted
on the /dev/dsk/c5t4d3p0 variant an inappropriate ioctl for device
error will result.

The device names within the /dev directory are typically symbolic
links to much longer topological names in the /device directory.

In Solaris cd/dvd/bd players seem to be treated as disks and so are
found in the /dev/rdsk directory. Tape drives appear in the /dev/rmt

There is also a sgen (SCSI generic) driver which by default does not
attach to any device. See the /kernel/drv/sgen.conf file to control
what is attached. Any attached device will have a device name of
the form /dev/scsi/c5t4d3 .

Listing available SCSI devices in Solaris seems to be a challenge.
"Use the 'format' command" advice works but seems a very dangerous
way to list devices. [It does prompt again before doing any damage.]
'devfsadm -Cv' cleans out the clutter in the /dev/rdsk directory,
only leaving what is "live". The "cfgadm -v" command looks promising.

Tru64 (osf) port
Any feedback on this platform welcome.

Win32 port
This port supports Windows NT, 2000, 2003++, XP, Vista and Windows 7
(i.e. not 95, 98, ME or earlier). It uses the Microsoft SCSI Pass Through
"Direct" (SPTD) rather than ASPI32 which requires a dll from Adaptec.

The source can be built in a cygwin environment and can run in a cygwin
bash shell. It can also run in a DOS shell if the cygwin1.dll is put in an
appropriate place.
Alternatively the source can be built with the MinGW compiler using its
MSYS shell. This removes the dependence on the cygwin1.dll file.

The device naming schemes attempt to follow what DOS does, with a few short
cuts. If volume "D:" is an ATAPI DVD drive then the actual file opened
is "\\.\D:". All device nodes of interest to sdparm have a leading "\\.\"
so if the user doesn't supply it, sdparm will. Thus 'sdparm d:' should work.
Note that volume names map to Windows partitions so there can be multiple
volume names per disk. SCSI devices (or those that use a SCSI command set)
can also be accessed via their "class" driver. These have names
like "PhysicalDrive<n>", "CDROM<n>" and "TAPE<n>" where <n> is a number
starting at 0. Since "PhysicalDrive" is tedious to type, a shortened
form "PD" is accepted.  So if "PD3" is a SCSI disk (or a SATA disk behind
a SAT layer) then 'sdparm pd3' should work.

Finally there is a lower level "SCSI<n>:" interface that addresses a SCSI
adapter. The device needs further sub-addressing in the form of a bus
number (also called a PathId), a target identifier and a lun (logical
unit number). sdparm uses this notation: "SCSI<n>:<bus>,<target>,<lun>".
The trailing ",<lun>" may be omitted in which case a lun of 0 is assumed.
Once a device has been "claimed" by an upper level "class" driver the
OS will not allow it to be accessed via the "SCSI<n>:" interface. Hence
this is only needed for special devices (e.g. with processor or SES
peripheral device type) that are not claimed by the class drivers.

The '--wscan' (or '-w') option has been added to show the mapping between
a class driver device name and its associated volume name(s). Here are some
 $ sdparm -w
PD0     [C]     FUJITSU   MHY2160BH         0000
PD1     [DF]    WD        2500BEV External  1.05  WD-WXE90

Now request bus types as well.

 $ sdparm -ww
PD0     [C]     <Ata  >  FUJITSU   MHY2160BH         0000
PD1     [DF]    <Usb  >  WD        2500BEV External  1.05  WD-WXE90
CDROM0  [E]     <Atapi>  MATSHITA DVD/CDRW UJDA775  CB03

Now request a SCSI adapter scan as well.
 $ sdparm -www
PD0     [C]     <Ata  >  FUJITSU   MHY2160BH         0000
PD1     [DF]    <Usb  >  WD        2500BEV External  1.05  WD-WXE90
CDROM0  [E]     <Atapi>  MATSHITA DVD/CDRW UJDA775  CB03

SCSI0:0,0,0   claimed=1 pdt=0h  FUJITSU   MHY2160BH         0000
SCSI1:0,0,0   claimed=1 pdt=5h  MATSHITA  DVD/CDRW UJDA775  CB03

And finally here is a more interesting example showing disks with no
Windows (2000) volumes, a tape drive and a weird unclaimed SCSI
pseudo device with BCC (Bridge Controller Commands) peripheral device
 $ sdparm -www
PD0     [C]     <Ata  >  ST380011A  8.01
PD1             <Scsi >  SEAGATE   ST373455SS        2189
PD2             <Scsi >  ATA       ST3160812AS       D
PD3             <Scsi >  SEAGATE   ST336754SS        0003
CDROM0  [F]     <Atapi>  HL-DT-ST DVDRAM GSA-4163B  A103
TAPE0           <Scsi >  SONY      SDT-7000          0192

SCSI0:0,0,0   claimed=1 pdt=0h dubious  ST380011  A                 8.01
SCSI1:0,0,0   claimed=1 pdt=5h          HL-DT-ST  DVDRAM GSA-4163B  A103
SCSI2:0,6,0   claimed=1 pdt=1h          SONY      SDT-7000          0192
SCSI5:0,17,0  claimed=1 pdt=0h          SEAGATE   ST373455SS        2189
SCSI5:0,19,0  claimed=1 pdt=0h          ATA       ST3160812AS       D
SCSI5:0,21,0  claimed=1 pdt=0h          SEAGATE   ST336754SS        0003
SCSI5:0,112,0 claimed=0 pdt=10h         LSI       PSEUDO DEVICE     2.34

Douglas Gilbert
16th April 2021