Provided by: sdparm_1.07-1_amd64 bug

NAME

       sdparm - access SCSI modes pages; read VPD pages; send simple SCSI commands.

SYNOPSIS

       sdparm  [--all]  [--clear=STR]  [--command=CMD]  [--dbd]  [--defaults] [--dummy] [--flexible] [--get=STR]
       [--help] [--hex] [--inquiry] [--long]  [--num-desc]  [--page=PG[,SPG]]  [--quiet]  [--readonly]  [--save]
       [--set=STR] [--six] [--transport=TN] [--vendor=VN] [--verbose] [--version] DEVICE [DEVICE...]

       sdparm --enumerate [--all] [--inquiry] [--long] [--page=PG[,SPG]] [--transport=TN] [--vendor=VN]

       sdparm --wscan [--verbose]

DESCRIPTION

       This  utility fetches and potentially changes SCSI device (e.g.  disk) mode pages. Inquiry data including
       Vital Product Data (VPD) pages can also be displayed. Commands associated with starting and stopping  the
       medium;  loading  and  unloading  the  medium; and other housekeeping function may also be issued by this
       utility.

       Of the three invocations shown in the synopsis, the first is the most general. The  second  variant  that
       uses  --enumerate  is  for  dumping information held in sdparm's internal tables. The last variant is for
       Windows only and lists the available device names; see the OPTIONS entry for --wscan.

       If no options (other than DEVICE) are given then a selection of common mode page fields for  that  device
       are listed. If the --long option is also given then a description of the fields is placed on the right of
       each line. If the --all option is given then all known mode page  fields  for  that  device  are  listed.
       Individual  fields can be displayed with the --get=STR option (e.g. '--get=WCE' to fetch the state of the
       Writeback Cache Enable field).

       This utility completes with an exit status of 0 when successful. For other values  see  the  EXIT  STATUS
       section below.

       One  or  more DEVICE arguments can be given. The utility will essentially apply the given options to each
       DEVICE in the list.  If an error is detected, it is noted and the utility continues.  Error value 5 (file
       open  or  close  problem) is treated as lower priority when other errors are detected. The exit status is
       the most recently detected error value (excluding error value 5 if other errors have been  detected).  If
       all actions succeed the exit status is zero.

       By  default this utility shows mode pages that are common to all transport protocols. These are termed as
       "generic" mode pages.  If there is no match on a generic  mode  page  name  or  field  then  those  pages
       specific  to the SAS transport are checked.  Transport protocol specific mode pages are selected with the
       --transport=TN option. See the TRANSPORT section below.  Vendor specific mode pages are selected with the
       --vendor=VN option.  See the VENDORS section below.

       Although  originally  for SCSI disks (or storage devices that appear to the OS as SCSI disks) many of the
       mode pages are for other SCSI device types.  These include CD/DVD players that  use  the  ATAPI  (or  any
       other) transport, SCSI tapes drives and SCSI enclosures.

       When  the  --inquiry  option is given without a page number then the Device Identification VPD page (page
       number 0x83) is requested and if found it is decoded and output. If no page number is given and the --all
       option is given then a list of VPD page names (but not their contents) supported by the DEVICE is output.
       When both the --inquiry and --page=PG options are given  then  the  VPD  page  can  be  specified  as  an
       abbreviation  (e.g.  "sp"  for  the  SCSI  ports VPD page) or numerically (e.g. "0x88"). If a VPD page is
       returned by the DEVICE but sdparm cannot decode it or the --hex option is given then it is output in hex.

OPTIONS

       Mandatory arguments to long options are mandatory for short options  as  well.   If  an  option  takes  a
       numeric  argument  then  that  argument  is assumed to be decimal unless otherwise indicated (e.g. with a
       leading "0x" or a trailing "h"). The options are in alphabetical order, based on the long option name.

       -a, --all
              output all recognized fields for the device type (e.g. disk) of the DEVICE.  Without  this  option
              (or  the  --page=PG[,SPG]  option)  the  default  action is to output a relatively small number of
              commonly used fields from different pages. When a specific (mode) page number is  given  with  the
              --page=PG[,SPG] option then all the fields of that page are output (irrespective of the setting of
              this option). For this option's action when used with the --enumerate  option  see  the  ENUMERATE
              section below.

       -c, --clear=STR
              In  its  simplest  form  STR contains a field acronym_name or a field numerical descriptor. In the
              absence of an explicit value argument (e.g. '--clear=WCE=1'), the field has its value  cleared  to
              zero.  See the PARAMETERS section below.

       -C, --command=CMD
              Perform  given  CMD.  See section below on COMMANDS. To enumerate supported commands use '-e -C x'
              (using any CMD name, valid or otherwise).

       -B, --dbd
              disable block descriptors. This is a bit in MODE SENSE cdbs that rarely needs to be set. One known
              case is a MODE SENSE 6 issued to a Reduced Block Commands (RBC) device where the RBC standard says
              it shall be set.

       -D, --defaults
              sets the given mode page to its default values. Requires the --page=PG[,SPG] option to be given to
              specify  the  mode page. To make the default mode page values also the saved mode page values, use
              the --save option as well.

       -d, --dummy
              when set inhibits changes being placed in the DEVICE's mode page.   Instead  the  mode  data  that
              would  have been sent to a MODE SELECT command, is output in ASCII hex to the console. This option
              is mainly for testing.

       -e, --enumerate
              lists out descriptive information about the pages and fields known to this  utility.  Ignores  the
              DEVICE  argument  and  other  options  apart  from  the --all, --inquiry, --long, --page=PG[,SPG],
              --transport=TN and --vendor=VN. If --enumerate is given  without  other  options  then  the  known
              (generic) mode pages are listed.  See the ENUMERATE section below.

       -f, --flexible
              Some  devices,  bridges  and/or  drivers attempt crude transformations between mode sense 6 and 10
              byte commands without correctly rebuilding the response.  This  will  cause  the  response  to  be
              mis-interpreted  (usually  with  an error saying the response is malformed). With this option, the
              length of the response is checked, and if it looks wrong, various corrections are attempted.  This
              option  will also allow mode pages that don't belong to the current device's peripheral type to be
              listed.

       -g, --get=STR
              In its simplest form STR contains a field acronym_name or a field numerical descriptor. The  field
              is  fetched  from mode page. See the PARAMETERS section below. The --long and --hex options effect
              the output format. Also if a value of "1" is given (e.g. '--get=WCE=1') only the current value  is
              output (i.e. not the change mask, the default value and the saved value).

       -h, --help
              output the usage message then exit.

       -H, --hex
              rather  than  trying  to  decode  mode  (or  VPD) pages, print them out in hex. When used with the
              --get=STR option the corresponding current, changeable, default and saved  values  are  output  in
              hex,  prefixed  by  "0x" and space separated. If a value of "1" is given with the --get=STR option
              (e.g. '--get=WCE=1') then only the current value is output in hex, prefixed by "0x". If a value of
              "2"  is  given  with  the  --get=STR  option  then  only the current value is output as a (signed)
              integer. This option can be used multiple times (e.g. '-HH'). Useful with the ATA Information  VPD
              page  which  usually outputs its IDENTIFY (PACKET) DEVICE response in 16 bit hex words; with '-HH'
              outputs that response in hex bytes; with '-HHH' outputs the same response in a format suitable for
              'hdparm --Istdin' to decode.

       -i, --inquiry
              output  INQUIRY  VPD  pages.  In  the  absence of this option the default action is to output mode
              pages. If the --inquiry option is  given  without  the  --page=PG[,SPG]  option  then  the  device
              identification  VPD  page  (0x83)  is  decoded and output. If this option and the --all option are
              given then the supported VPD pages page (0x0) is decoded and output.

       -l, --long
              output extra information. In the case of mode page fields a description (with units if applicable)
              is  output  to the right. If used twice, then for some fields more information about its values is
              given on one or more following lines, each prefixed by a tab character. For usage with --enumerate
              see the ENUMERATE section below.

       -n, --num-desc
              for  a  mode  page  that can have descriptors, the number of descriptors for the given page on the
              DEVICE is output. Otherwise 0 is output.

       -p, --page=PG[,SPG]
              supply the page number (PG) and optionally the sub page number (SPG) of the mode (or VPD) page  to
              fetch.  These numbers are interpreted as decimal unless prefixed with "0x" or a trailing. Sub page
              numbers are only valid for mode pages (not VPD pages). Alternatively an abbreviation  for  a  page
              can be given (see next entry).

       -p, --page=STR
              a  two  or  three  letter  abbreviation for a page can be given. Known mode page abbreviations are
              checked first followed by known VPD page  abbreviations.   For  example  '--page=ca'  matches  the
              caching mode page. If no match is found then an error is issued and a list of possibilities in the
              current context is given (so '-p x' can be quite useful). If the STR  matches  a  known  VPD  page
              abbreviation  then  the  --inquiry option is assumed. For usage with --enumerate see the ENUMERATE
              section below.

       -q, --quiet
              suppress output of device name followed by the vendor, product and revision strings  fetched  from
              an INQUIRY response. Without this option such a line is typically the first line output by sdparm.
              Reduces output from the device identification VPD page, typically to one line (or none)  for  each
              of di_lu, di_port, di_target and di_asis.

       -r, --readonly
              override  other  logic to open DEVICE in read-only mode. This option may be useful if a command is
              being sent to an ATA disk via a SCSI command set. For example in Linux '-C stop' may require  this
              option to stop an ATA disk being restarted immediately.

       -S, --save
              when  a  mode  page is being modified (by using the --clear=STR and/or --set=STR options) then the
              default action is to modify only the current values mode page. When this option is given then  the
              corresponding  value(s) in the saved values mode page is also changed. The next time the device is
              power cycled (or reset) the saved values mode page becomes (i.e. is copied to) the current  values
              mode page. See NOTES section below.

       -s, --set=STR
              in  its  simplest  form  STR contains a field acronym_name or a field numerical descriptor. In the
              absence of an explicit value, each acronym_name has its value set to (all) ones. This means  a  16
              bit  field  will  be  set  to 0xffff which is 65535 in decimal. Alternatively each acronym_name or
              numerical descriptor may be followed by "=<n>" where <n> is the value to set that  field  to.  See
              the PARAMETERS section below.

       -6, --six
              The  default  action  of this utility is to issue MODE SENSE and MODE SELECT SCSI commands with 10
              byte cdbs. When this option is given the 6 byte cdb variants are used. RBC and  old  SCSI  devices
              may  need  this  option.  This  utility outputs a suggestion to use this option if the SCSI status
              indicates that the 10 byte cdb variant is not supported.

       -t, --transport=TN
              Specifies the transport protocol where TN is either a number in the range 0 to 15  (inclusive)  or
              an  abbreviation  (e.g. "fcp" for the Fibre Channel Protocol). One way to list available transport
              protocols numbers and their associated abbreviations is to  give  an  invalid  transport  protocol
              number such as '-t x'; another way is '-e -l'.

       -M, --vendor=VN
              Specifies  the  vendor  (i.e.  manufacturer)  where  VN  is  either  a  number  (0  or more) or an
              abbreviation (e.g. "sea" for Seagate disk vendor specific).  One  way  to  list  available  vendor
              numbers  and  their  associated  abbreviations is to give an invalid vendor number such as '-M x';
              another way is '-e -l'.

       -v, --verbose
              increase the level of verbosity, (i.e. debug output). In some cases more decoding  is  done  (e.g.
              fields within a standard INQUIRY response).

       -V, --version
              print the version string and then exit.

       -w, --wscan
              this  option  is  available  in  Windows only. It lists storage device names and the corresponding
              volumes, if any. When used twice it adds the "bus type" of the closest transport (e.g. a SATA disk
              in  a  USB  connected  enclosure  has  bus type Usb). When used three times a SCSI adapter scan is
              added. When used four times only a SCSI adapter scan is shown.  See examples below and the  "Win32
              port" section in the README file.

NOTES

       A  mode  page  for  which  no  abbreviation  is known (e.g. a vendor specific mode page) can be listed in
       hexadecimal by using the option combination '--page=PG --hex'.

       Numbers input to sdparm (e.g. in the command line arguments) are assumed to be in decimal unless there is
       a  hexadecimal  indicator.  A hexadecimal indicator is either a leading '0x' or '0X' (i.e. the C language
       convention) or a trailing 'h' or 'H' (i.e. the convention used at www.t10.org ). In the case  of  --page=
       either  a  string or number is expected, so hex numbers like 'ch' (12) should be prefixed by a zero (e.g.
       '0ch').

       The SPC-4 draft (rev 2) says that devices that implement no distinction between current and  saved  pages
       can  return  an  error  (ILLEGAL  REQUEST,  invalid field in cdb) if the SP bit (which corresponds to the
       --save option) is _not_ set. In such cases the --save option needs to be given.

       If the --save option is given but the existing mode page indicates (via its PS bit) that the page is  not
       savable,  then  this  utility  generates an error message. That message suggests to try again without the
       --save option.

       Since the device identification VPD page (acronym_name  "di")  potentially  contains  a  lot  of  diverse
       designators,  several associated acronyms are available. They are "di_lu" for designators associated with
       the addressed logical unit, "di_port" for designators associated with the target port (which the  command
       arrived  via)  and  "di_target"  for  designators  associated  with  the target device. When "di" is used
       designators are grouped by lu, then port and then target device.  To see all designators decoded  in  the
       order that they appear in the VPD page use "di_asis".

       Only  those  VPD  pages  defined by t10.org are decoded by this utility. SPC-4 sets aside VPD pages codes
       from 0xc0 to 0xff (inclusive) for vendor specific pages some of which are decoded in the sg_vpd utility.

       In the linux kernel 2.6 series any device node that understands a SCSI command set (e.g. SCSI  disks  and
       CD/DVD  drives)  may be specified. More precisely the driver that "owns" the device node must support the
       SG_IO ioctl. In the lk 2.4 series only SCSI generic (sg) device nodes support the SG_IO ioctl. However in
       the lk 2.4 series other SCSI device nodes are mapped within this utility to their corresponding sg device
       nodes. So if there is a SCSI disk at /dev/sda then 'sdparm /dev/sda' will work in both the lk 2.6 and  lk
       2.4  series.  However if there is an ATAPI cd/dvd drive at /dev/hdc then 'sdparm /dev/hdc' will only work
       in the lk 2.6 series.

       In the Linux 2.6 series, especially with ATA disks, using sdparm to stop (spin down) a disk  may  not  be
       sufficient  and  other  mechanisms will start the disk again some time later. The user might additionally
       mark the disk as "offline" with 'echo offline > /sys/block/sda/device/state' where sda is the block  name
       of the disk. To restart the disk "offline" can be replaced with "running".

PARAMETERS

       In  their  simplest  form  the  --clear=,  --get=  and  --set=  options  (or  their  short forms) take an
       acronym_name such as "WCE". In the case of '--get=WCE' the value  of  "Writeback  Cache  Enable"  in  the
       caching  mode page will be fetched. In the case of '--set=WCE' that bit will be set (to one). In the case
       of '--clear=WCE' that bit will be cleared (to zero). When an acronym_name is given then the mode page  is
       imputed from that acronym_name (e.g. WCE is in the caching mode page).

       Instead   of  an  acronym_name  a  field  within  a  mode  page  can  be  described  numerically  with  a
       <start_byte>:<start_bit>:<num_bits> tuple. These are the <start_byte> (origin 0) within the mode page,  a
       <start_bit>  (0  to  7  inclusive)  and  <num_bits>  (1  to  64  inclusive).  For  example, the low level
       representation of the RCD bit (the "Read Cache Disable bit in the caching  mode  page)  is  "2:0:1".  The
       <start_byte>  can optionally be given in hex (e.g. '--set=0x2:0:1' or '--set=2h:0:1'). With this form the
       --page= option is required to establish which mode page is to be used.

       Either form can optionally be followed by "=<val>". By default <val> is decimal but can be given  in  hex
       in the normal fashion. Here are some examples: '--set=2h:0:1=1h' and '-s MRIE=0x3'. When the acronym_name
       or numeric form following --clear= is not given an explicit '=<val>' then the  value  defaults  to  zero.
       When  the  acronym_name or numeric form following --set= is not given an explicit '=<val>' then the value
       defaults  to  "all  ones"  (i.e.  as  many  as  <num_bits>  permits).  For  example   '--clear=WCE'   and
       '--clear=WCE=0'  have  the  same  meaning: clear Writeback Cache Enable or, put more simply: turn off the
       writeback cache.

       Multiple fields within the  same  mode  page  can  be  changed  by  giving  a  comma  separated  list  of
       acronym_names and/or the numerical form. For example: '--set=TEST,MRIE=6'.

       Some  mode page have multiple descriptors. They typically have a fixed header section at the start of the
       mode page that includes a field containing the number of descriptors that follow. Following the header is
       a  variable  number  of  descriptors.  An  example  is  the  SAS  Phy  Control and Discover mode page. An
       acronym_name may include a trailing '.<num>' where "<num>" is a descriptor number (origin 0). For example
       '-t  sas  -g  PHID.0'  and  '-t sas -g PHID' will yield the phy identifier of the first descriptor of the
       above mode page; '-t sas -g PHID.1' will yield the phy identifier of the second descriptor.

ENUMERATE

       The --enumerate option essentially dumps  out  static  information  held  by  this  utility.  A  list  of
       --enumerate  variants  and their actions follows. For brevity subsequent examples of options are shown in
       their shorter form.

           --enumerate          list generic mode page information
           -e --all             list generic mode page contents
                                (i.e. parameters)
           -e --page=rw         list contents of read write error
                                recovery mode page
           -e --inquiry         list VPD pages this utility can decode
           -e --long            list generic mode pages, transport
                                protocols, mode pages for each
                                supported transport protocol and
                                supported commands
           -e -l --all          additionally list the contents of
                                each mode page
           -e --transport=fcp   list mode pages for the fcp
                                transport protocol
           -e -t fcp --all      additionally list the contents of
                                each mode page
           -e --vendor=sea      list vendor specific mode pages for
                                "sea" (Seagate)
           -e -M sea --all      additionally list the contents of vendor
                                specific mode pages for "sea" (Seagate)
           -e -p pcd -l         list contents of SAS phy control and
                                discovery mode page plus (due to "-l")
                                some descfriptor format information

       When known mode pages are listed (via the --enumerate  option) each line  starts  with  a  two  or  three
       letter abbreviation. This is followed by the page number (in hex prefixed by "0x") optionally followed by
       a comma and the subpage number. Finally the descriptive name of the mode page (e.g. as found in SPC-4) is
       output.

       When  known  parameters  (fields) of a mode page are listed, each line starts with an acronym (indented a
       few spaces). This will match (or be an acronym for) the description for that field found in  the  (draft)
       standards.  Next are three numbers, separated by colons, surrounded by brackets. These are the start byte
       (in hex, prefixed by "0x") of the beginning of the field within  the  mode  page;  the  starting  bit  (0
       through  7  inclusive) and then the number of bits. The descriptive name of the parameter (field) is then
       given. If appropriate the descriptive name includes units (e.g. "(ms)" means the units are milliseconds).
       Adding  the  '-ll'  option  will  list  information  about  possible  field values for selected mode page
       parameters.

       Mode parameters for which the num_bits is greater than 1 can be viewed as unsigned integers. Often 16 and
       32  bit  fields  are  set  to  0xffff  and 0xffffffff respectively (all ones) which usually has a special
       meaning (see drafts). This utility outputs such values as "-1" to save space (rather than their  unsigned
       integer  equivalents).  "-1"  can  also  be  given  as  the  value  to  a  mode  page field acronym (e.g.
       '--set=INTT=-1' sets the interval timer field in  the  Informational  Exceptions  control  mode  page  to
       0xffffffff).

TRANSPORTS

       SCSI  transport protocols are a relatively specialized area that can be safely ignored by the majority of
       users.

       Some transport protocols have protocol specific mode pages. These are  usually  the  disconnect-reconnect
       (0x2),  the  protocol  specific  logical unit (0x18) and the protocol specific port (0x19) mode pages. In
       some cases the latter mode page has several subpages. The most common  transport  protocol  abbreviations
       likely to be used are "fcp", "spi" and "sas".

       Many of the field names are re-used in the same position so the acronym_name namespaces have been divided
       between generic mode pages (i.e. when the --transport= option is _not_ given) and a  namespace  for  each
       transport  protocol.  A LUPID field from the protocol specific logical unit (0x18) mode page and the PPID
       field from protocol specific port (0x19) mode page are included in the generic modes pages;  this  is  so
       the  respective  (transport)  protocol identifiers can be seen. In most cases the user will know what the
       "port" transport is (i.e. the same transport as the HBA in the computer) but the logical unit's transport
       could be different.

VENDORS

       SCSI  leaves  a lot of space for vendor specific information. Often this is described in product manuals.
       The --vendor=VN (or -M=VN) option allows known vendor specific mode pages to be examined and/or  modified
       by acronym.

       In  this  utility  the  syntax  and  semantics  of vendor specific mode pages is very similar to those of
       transport protocol specific mode pages. Both cannot be specified together. Vendor  specific  modes  pages
       can still be accessed numerically (as shown at the end of the EXAMPLES section).

COMMANDS

       The command option sends a SCSI command to the DEVICE. If the command fails then this is reflected in the
       non-zero exit status.  To obtain more information about the error use the -v option.

       capacity
              sends a READ CAPACITY command (valid for disks and cd/dvd media). If successful yields "blocks:  "
              [the  number  of  blocks],  "block_length:  "  [typically either 512 or 2048] and "capacity_mib: "
              [capacity in MibiBytes (1048576 byte units)].

       eject  stops the medium and ejects it from the device.  Note that ejection (by command or button) may  be
              prevented  in  which  case  the  'unlock'  command may be useful in extreme cases.  Typically only
              appropriate for cd/dvd drives and disk drives with removable media. Objects  if  sent  to  another
              peripheral device type (but objection can be overridden with '-f' option).

       load   loads  the  medium and and starts it (i.e. spins it up).  See 'eject' command for supported device
              types.

       profile
              lists the various formats that a CD/DVD/HD-DVD/BD drive supports. These are called  "profiles"  in
              the MMC standard. The profiles are listed one per line.  If media is in the drive then the profile
              that matches the media (if any) has an "*" to the right of the line.

       ready  sends the "Test Unit Ready" SCSI command to the DEVICE. No error is reported if  the  device  will
              respond  to data requests (e.g. READ) in a reasonable timescale. For example, if a disk is stopped
              then it will report "not ready". All devices should respond to this command.

       sense  sends a REQUEST SENSE command. It reports a hardware threshold  exceeded,  warning  or  low  power
              condition  if  flagged. If a progress indication is present (e.g. during a format) then it will be
              output as a percentage. Yields a process status of 0 if the command succeeds and the sense key  is
              0;  else yields 1. The --quiet option can be used to lessen output, and --hex to output sense data
              in hex.

       speed=SPEED
              permits the speed of a CD, DVD, HD_DVD or BD disc in a drive to be set (or at  least  influenced).
              It  has  this format: --command=speed=SPEED where SPEED is in kilobytes per second. In this case a
              kilobyte is 1000 bytes. The "times one" speed for a CD is 176.4 kB/s, for a DVD is 1350  kB/s  and
              for  both  HD-DVD and BD it is 4500 kB/s. If SPEED is zero then the drive is set to the speed that
              it considers gives optimal performance.  This command sends a SET  STREAMING  multi-media  command
              (MMC)  to the drive.  The EXACT bit is clear so the drive will round the given SPEED as necessary.
              The command is designed to control read speed; setting write speed should  be  left  to  "burning"
              programs.

       start  starts  the  medium  (i.e.  spins it up). Harmless if medium has already been started. See 'eject'
              command for supported device types. If the DEVICE is an ATA disk in Linux the '--readonly'  option
              may be required.

       stop   stops  the  medium  (i.e. spins it down). Harmless if medium has already been stopped. See 'eject'
              command for supported device types. If the DEVICE is an ATA disk in Linux the '--readonly'  option
              may be required. See the NOTES section above.

       sync   sends a SYNCHRONIZE CACHE command. The device should flush any data held in its (volatile) buffers
              to the media.

       unlock tells a device to allow medium removal. It uses the SCSI "prevent allow medium  removal"  command.
              This  is  desperation  stuff, possibly overriding a prevention applied by the OS on a mounted file
              system. The "eject" utility (from the "eject" package) is more graceful and should be tried first.
              This command is only appropriate for devices with removable media.

       For  loading  and  ejecting  tapes  the  mt utility should be used (i.e. not these commands). The 'ready'
       command is valid for tape devices.

EXAMPLES

       To list the common (generic) mode parameters of a disk:

          sdparm /dev/sda

       To list the designators within the device identification VPD page of a disk:

          sdparm --inquiry /dev/sda

       To see all parameters for the caching mode page:

          sdparm --page=ca /dev/sda

       To see all parameters for the caching mode page with parameter descriptions to the right:

          sdparm --page=ca --long /dev/sda

       To get the WCE values (current changeable default and saved) in hex:

          sdparm -g WCE -H /dev/sda
       0x01 0x00 0x01 0x01

       To get the WCE current value in hex:

          sdparm -g WCE=1 -H /dev/sda
       0x01

       To set the "Writeback Cache Enable" bit in the current values page:

          sdparm --set=WCE /dev/sda

       To set the "Writeback Cache Enable" bit in the current and saved values page:

          sdparm --set=WCE --save /dev/sda

       To set the "Writeback Cache Enable" and clear "Read Cache Disable":

          sdparm --set=WCE --clear=RCD --save /dev/sda

       The previous example can also by written as:

          sdparm -s WCE=1,RCD=0 -S /dev/sda

       To re-establish the manufacturer's defaults in the current and saved values of the caching mode page:

          sdparm --page=ca --defaults --save /dev/sda

       If an ATAPI cd/dvd drive is at /dev/hdc then its common (mode) parameters could be listed in the  lk  2.6
       series with:

          sdparm /dev/hdc

       If there is a DVD in the drive at /dev/hdc then it could be ejected in the lk 2.6 series with:

          sdparm --command=eject /dev/hdc

       If the ejection is being prevented by software then that can be overridden with:

          sdparm --command=unlock /dev/hdc

       One  disk  vendor  has  a  "Performance  Mode"  bit  (PM) in the vendor specific unit attention mode page
       [0x0,0x0]. PM=0 is server mode (the default) while PM=1 is desktop mode. Desktop mode can  be  set  (both
       current and saved values) with:

          sdparm --page=0 --set=2:7:1=1 --save /dev/sda

       The  resultant  change  can  be  viewed  in hex with the --hex option as there are no acronyms for vendor
       extensions yet. The PM bit is now covered by vendor specific  mode  pages  and  the  above  can  also  be
       accomplished with:

          sdparm --vendor=sea --set=PM --save /dev/sda

       What  follows are some examples from Windows using the '--wscan' option.  The idea is to list the storage
       device names on the system that might be invoked by other uses of sdparm.

         # sdparm --wscan
       PD0     [C]     FUJITSU   MHY2160BH         0000
       PD1     [DF]    WD        2500BEV External  1.05  WD-WXE90
       CDROM0  [E]     MATSHITA DVD/CDRW UJDA775  CB03

       So 'sdparm -a CDROM0' and 'sdparm -a E' will show all the (known)  mode  page  fields  for  the  Matshita
       DVD/CD  drive.  By  using  the  '--wsacan' option twice, the bus type (as seen by the OS) is added to the
       output:

         # 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

       And the pattern continues to add a SCSI adapter scan. This may be useful if there are specialized storage
       related devices (e.g. a SES device in an enclosure) but does add much extra information in this case.

         # 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

EXIT STATUS

       To  aid  scripts that call sdparm, the exit status is set to indicate success (0) or failure (1 or more).
       Note that some of the lower values correspond to the SCSI sense key values. The exit status values are:

       0      success

       1      syntax error. Either illegal command line options, options with bad arguments or a combination  of
              options that is not permitted.

       2      the  DEVICE  reports  that  it  is not ready for the operation requested. The device may be in the
              process of becoming ready (e.g.  spinning up but not at speed) so the utility  may  work  after  a
              wait.

       3      the DEVICE reports a medium or hardware error (or a blank check). For example an attempt to read a
              corrupted block on a disk will yield this value.

       5      the DEVICE reports an "illegal  request"  with  an  additional  sense  code  other  than  "invalid
              operation  code".  This  is  often  a supported command with a field set requesting an unsupported
              capability. For commands that require a "service action" field this value can  indicate  that  the
              command is not supported.

       6      the  DEVICE  reports a "unit attention" condition. This usually indicates that something unrelated
              to the requested command has occurred (e.g. a device reset) potentially before  the  current  SCSI
              command  was  sent.  The  requested  command  has  not been executed by the device. Note that unit
              attention conditions are usually only reported once by a device.

       9      the DEVICE reports an illegal request with an additional sense code of  "invalid  operation  code"
              which means that it doesn't support the requested command.

       11     the  DEVICE  reports an aborted command. In some cases aborted commands can be retried immediately
              (e.g. if the transport aborted the command due to congestion).

       15     the utility is unable to open, close or use the given  DEVICE.   The  given  file  name  could  be
              incorrect or there may be permission problems. Adding the -v option may give more information.

       20     the  DEVICE  reports it has a check condition but "no sense".  Some polling commands (e.g. REQUEST
              SENSE) can react this way.  It is unlikely that this value will occur as an exit status.

       21     the DEVICE reports a "recovered error". The  requested  command  was  successful.  Most  likely  a
              utility will report a recovered error to stderr and continue, probably leaving the utility with an
              exit status of 0 .

       33     the command sent to DEVICE has timed out. This occurs in Linux only;  in  other  ports  a  command
              timeout will appear as a transport (or OS) error.

       97     the response to a SCSI command failed sanity checks.

       98     the  DEVICE  reports  it  has  a  check  condition but the error doesn't fit into any of the above
              categories.

       99     any errors that can't be categorized into values 1 to 98  may  yield  this  value.  This  includes
              transport and operating system errors after the command has been sent to the device.

       Most  of  the  error conditions reported above will be repeatable (an example of one that is not is "unit
       attention") so the utility can be run again with the -v option (or several) to obtain more information.

AUTHORS

       Written by Douglas Gilbert.

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright © 2005-2012 Douglas Gilbert
       This software is distributed under a FreeBSD license. There is NO warranty; not even for  MERCHANTABILITY
       or FITNESS FOR A PARTICULAR PURPOSE.

WEB SITE

       There is a web page discussing this package at http://sg.danny.cz/sg/sdparm.html .

SEE ALSO

       hdparm(hdparm),    sg_modes,   sg_wr_mode,   sginfo,   sg_inq,   sg_vpd,   sg_scan(all   in   sg3_utils),
       smartmontools(smartmontools.sourceforge.net), mt, eject(eject),