Provided by: sg3-utils_1.33-1_i386 bug

NAME

       sg_format  -  format  or  resize  a SCSI disk (perhaps change its block
       size)

SYNOPSIS

       sg_format    [--cmplst=0|1]    [--count=COUNT]    [--dcrt]    [--early]
       [--fmtpinfo=FPI]  [--format]  [--help] [--long] [--pfu=PFU] [--pie=PIE]
       [--pinfo]  [--poll=PT]  [--resize]  [--rto_req]  [--security]   [--six]
       [--size=SIZE] [--verbose] [--version] [--wait] DEVICE

DESCRIPTION

       Not  all  SCSI direct access devices need to be formatted and some have
       vendor specific formatting procedures. SCSI disks with  rotating  media
       are  probably  the  largest  group  that do support a 'standard' format
       operation. They are typically factory formatted to a block size of  512
       bytes   with  the  largest  number  of  blocks  that  the  manufacturer
       recommends. The manufacturer's recommendation typically leaves aside  a
       certain  number of tracks, spread across the media, for reassignment of
       blocks to logical block addresses during the life of the disk.

       This utility can format modern SCSI disks and potentially change  their
       block  size  (if  permitted)  and  the  block  count  (i.e.  number  of
       accessible blocks on the media also known as  "resizing").  Resizing  a
       disk  to  less  than  the  manufacturer's  recommended  block  count is
       sometimes called "short stroking" (see  NOTES  section).  Resizing  the
       block  count while not changing the block size may not require a format
       operation. The SBC-2  standard  (see  www.t10.org)  has  obsoleted  the
       "format  device" mode page. Many of the low level details found in that
       mode page are now left up to the discretion of the manufacturer.

       When this utility is used without options (i.e.  it  is  only  given  a
       DEVICE  argument) it prints out the existing block size and block count
       derived from two sources. These two sources are a block  descriptor  in
       the  response  to  a  MODE  SENSE  command  and  the response to a READ
       CAPACITY command. The reason for this  double  check  is  to  detect  a
       "format  corrupt" state (see NOTES section). This usage will not modify
       the disk.

       When this utility is used with the "--format" (or "-F") option it  will
       attempt  to  format the given DEVICE. There is a 10 second pause during
       which time the user  is  invited  twice  (5  seconds  apart)  to  abort
       sg_format.  This  occurs  just prior the SCSI FORMAT UNIT command being
       issued. See the NOTES section for more information.

       Protection information is optional and is made up of 8 additional bytes
       associated  with  each logical block. Four protection types are defined
       with protection type 0 being no additional protection  bytes.  See  the
       PROTECTION TYPES section below for more information.

OPTIONS

       Arguments to long options are mandatory for short options as well.  The
       options are arranged in alphabetical order based  on  the  long  option
       name.

       -C, --cmplst=0 | 1
              sets  the CMPLST ("complete list") bit in the FORMAT UNIT cdb to
              0 or 1.  The default is 1  in  which  case  the  existing  GLIST
              (grown  list)  is  ignored.  If the value is 0 then the existing
              GLIST is taken into account. See the  LISTS  section  below.  In
              most cases this bit should be left set; some MO disk drives need
              this bit cleared.

       -c, --count=COUNT
              where COUNT is the number of blocks to be formatted or media  to
              be  resized  to.  Can  be used with either --format or --resize.
              With --format this option need not be given in which case it  is
              assumed  to  be  zero. With --format the interpretation of COUNT
              is:
                (COUNT > 0) : only format the first COUNT blocks and READ
                              CAPACITY will report COUNT blocks after format
                (COUNT = 0) and block size  unchanged  :  use  existing  block
              count
                (COUNT = 0) and block size changed : recommended maximum block
                                                     count for new block size
                (COUNT = -1) : use recommended maximum block count
                (COUNT < -1) : illegal
              With  --resize  this  option  must  be  given and COUNT has this
              interpretation:
                (COUNT > 0) : after resize READ CAPACITY will report COUNT
                              blocks
                (COUNT = 0) : after resize READ CAPACITY will report 0 blocks
                (COUNT = -1) : after resize READ CAPACITY will report its
                               maximum number of blocks
                (COUNT < -1) : illegal
              In both cases if the given COUNT exceeds the maximum  number  of
              blocks (for the block size) then the disk reports an error.  See
              NOTES section below.

       -D, --dcrt
              this option sets the DCRT  bit  in  the  FORMAT  UNIT  command's
              parameter   list   header.   It  will  "disable  certification".
              Certification verifies that blocks are usable during the  format
              process.  Using  this  option may speed the format.  The default
              action of this utility (i.e. when this option is not  given)  is
              to  clear the DCRT bit thereby requesting "media certification".
              When the DCRT bit is set, the FOV bit must  also  be  set  hence
              sg_format does that.

       -e, --early
              during a format operation, The default action of this utility is
              to poll the disk every 60 seconds to determine the  progress  of
              the  format  operation until it is finished. When this option is
              given this utility will exit "early", that is  as  soon  as  the
              format  operation  has  commenced. Then the user can monitor the
              progress of the ongoing format operation  with  other  utilities
              (e.g.  sg_turs(8) or sg_requests(8)). This option and --wait are
              mutually exclusive.

       -f, --fmtpinfo=FPI
              sets the FMTPINFO field in  the  FORMAT  UNIT  cdb  to  a  value
              between  0  and  3.   The default value is 0. The FMTPINFO field
              from SBC-3 revision 16 is a 2 bit field (bits 7 and 6 of byte  1
              in  the  cdb). Prior to that it was a single bit field (bit 7 of
              byte 1 in the cdb) and there  was  an  accompanying  bit  called
              RTO_REQ  (bit  6  of  byte 1 in the cdb). The deprecated options
              "--pinfo" and "--rto-req" represent the older usage. This option
              should  be used in their place. See the PROTECTION TYPES section
              below for more information.

       -F, --format
              issue a SCSI FORMAT UNIT command.  This  will  destroy  all  the
              data  held  on the media.  This option is required to change the
              block size of a disk. The user is given a 10 second  count  down
              to  ponder the wisdom of doing this, during which time control-C
              (amongst other Unix commands) can be used to kill  this  process
              before  it does any damage. See NOTES section for implementation
              details and EXAMPLES section for typical use.

       -h, --help
              print out the usage information then exit.

       -l, --long
              the default action of this utility is to assume 32  bit  logical
              block addresses. With 512 byte block size this permits more than
              2 terabytes (almost 2 ** 41 bytes) on a single disk. This option
              selects  commands  and  parameters that allow for 64 bit logical
              block addresses.  Specifically this option  sets  the  "longlba"
              flag  in the MODE SENSE (10) command and uses READ CAPACITY (16)
              rather than READ CAPACITY (10). If this option is not given  and
              READ  CAPACITY (10) or MODE SELECT detects a disk the needs more
              than 32 bits to represent its logical  blocks  then  it  is  set
              internally.  This  option  does  not set the LONGLIST bit in the
              FORMAT UNIT  command.  The  LONGLIST  bit  is  set  as  required
              depending  other  parameters  (e.g.  when '--pie=PIE' is greater
              than zero).

       -P, --pfu=PFU
              sets the "Protection Field Usage" field in the  parameter  block
              associated  with a FORMAT UNIT command to PFU. The default value
              is 0, the only other defined  value  currently  is  1.  See  the
              PROTECTION TYPES section below for more information.

       -q, --pie=PIE
              sets  the  "Protection Interval Exponent" field in the parameter
              block associated with a FORMAT UNIT command to PIE. The  default
              value is 0.  This field first appeared in SBC-3 revision 18.

       -p, --pinfo
              The option is deprecated, use the --fmtpinfo=FPI option instead.
              If used, then it sets bit 7 of byte 1 in the FORMAT UNIT cdb.

       -x, --poll=PT
              where PT is the type of poll used. If PT is 0 then a  TEST  UNIT
              READY  command  is  used,  otherwise  a REQUEST SENSE command is
              used. The default is currently 0 but this will change  to  1  in
              the near future. See the NOTES sections below.

       -r, --resize
              rather  than  format  the  disk,  it  can be resized. This means
              changing the number of blocks on the device reported by the READ
              CAPACITY   command.    This  option  should  be  used  with  the
              --count=COUNT option.  The contents of all logical blocks on the
              media remain unchanged when this option is used. This means that
              any resize operation can be reversed. This option cannot be used
              together with either --format or a --size=SIZE whose argument is
              different to the existing block size.

       -R, --rto_req
              The option is deprecated, use the --fmtpinfo=FPI option instead.
              If used, then it sets bit 6 of byte 1 in the FORMAT UNIT cdb.

       -S, --security
              sets  the  "Security Initialization" (SI) bit in the FORMAT UNIT
              command's initialization pattern descriptor within the parameter
              list.  According  to  SBC-3  the  default initialization pattern
              "shall be written using a security erasure write technique". See
              the NOTES section on the SCSI SANITIZE command.

       -6, --six
              Use  6  byte variants of MODE SENSE and MODE SELECT. The default
              action is to use the 10 byte variants. Some MO drives need  this
              option set when doing a format.

       -s, --size=SIZE
              where  SIZE  is  the  block  size  (i.e. number of bytes in each
              block) to format the device to. The default value is whatever is
              currently  reported  by  the  block  descriptor  in a MODE SENSE
              command. If the block size given by  this  option  is  different
              from  the  current  value  then a MODE SELECT command is used to
              change it prior to the FORMAT UNIT  command  being  started  (as
              recommended  in  the  draft  standard). Many SCSI disks have 512
              byte sectors by default and allow up to  16  bytes  extra  in  a
              sector   (i.e.   528  byte  sectors).   If  the  given  size  in
              unacceptable with the disk, most likely  an  "Invalid  field  in
              parameter  list" message will appear in sense data (requires the
              use of '-v' to decode sense data).

       -v, --verbose
              increase the level of verbosity,  (i.e.  debug  output).  "-vvv"
              gives a lot more debug output.

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

       -w, --wait
              the  default  format  action  is  to  set the "IMMED" bit in the
              FORMAT UNIT command's (short) parameter header. If  this  option
              (i.e.  --wait)  is  given  then  the  "IMMED" bit is not set. If
              --wait is given the FORMAT UNIT command waits until  the  format
              operation  completes  before returning its response. This can be
              many hours on large disks. This utility sets a 15  hour  timeout
              on such a FORMAT UNIT command!

LISTS

       The  SBC-3 draft (revision 29) defines PLIST, CLIST, DLIST and GLIST in
       section 4.13 on "Medium defects". Briefly, the PLIST is  the  "primary"
       list of manufacturer detected defects, the CLIST ("certification" list)
       contains those detected during the format operation,  the  DLIST  is  a
       list of defects that can be given to the format operation. The GLIST is
       the grown list which starts in the format process  as  CLIST+DLIST  and
       can  "grow"  later due to automatic reallocation (see the ARRE and AWRE
       bits in the read-write error recovery mode page  (see  sdparm(8)))  and
       use of the SCSI REASSIGN BLOCKS command (see sg_reassign(8)).

       The  CMPLST  bit  (controlled  by  the  --cmplst=0|1 option) determines
       whether the existing GLIST, when the format operation  is  invoked,  is
       taken  into  account.  The  sg_format  utility sets the FOV bit to zero
       which causes DPRY=0, so the PLIST is taken into account, and DCRT=0, so
       the CLIST is generated and used during the format process.

       The  sg_format  utility does not permit a user to provide a defect list
       (i.e. DLIST).

PROTECTION TYPES

       SBC-3 drafts have added several "protection types" to  the  "protection
       information"  introduced  in  the  SBC-2  standard. See the "protection
       information" section (section 4.21 in draft SBC-3 rev 29). 8  bytes  of
       protection  information  are  added  to  each  logical  block (a 2 byte
       "logical block guard"  (CRC),  a  2  byte  "logical  block  application
       guard",  and  a  4 byte "logical block reference tag"). SBC-3 defines 4
       protection types (types 0 to 4)  with  protection  type  0  meaning  no
       protection information is maintained.

       A  device  that  supports  protection information (i.e. supports one or
       more protection types of 1 or higher) sets the  "PROTECT"  bit  in  its
       standard  INQUIRY  response. It also sets the SPT field in the EXTENDED
       INQUIRY VPD  page  response  to  indicate  which  protection  types  it
       supports.  The  current  protection  type of a disk can be found in the
       "P_TYPE" and "PROT_EN" fields in the response of a READ  CAPACITY  (16)
       command (e.g. with the 'sg_readcap --long' utility).

       Given  that  a device supports a particular protection type, a user can
       then then choose to format that  disk  with  that  protection  type  by
       setting  the  "FMTPINFO"  and  "Protection  Field  Usage" fields in the
       FORMAT UNIT command. Those fields correspond to the --fmtpinfo=FPI  and
       the --pfu=PFU options in this utility. If FPI and PFU are both 0 (their
       default values) then protection type 0 is chosen. If FPI is 2  and  PFU
       is  0  then  protection type 1 is chosen. If FPI is 3 and PFU is 0 then
       protection type 2 is chosen. If FPI is 3 and PFU is 1  then  protection
       type 3 is chosen.

NOTES

       The SBC-2 standard states that the REQUEST SENSE command should be used
       for obtaining progress indication when the format command is  underway.
       However,  tests  on  a  selection  of  disks shows that TEST UNIT READY
       commands yield progress indications (but not REQUEST  SENSE  commands).
       So  the  current  version  of  this utility defaults to using TEST UNIT
       READY commands to poll the disk to find out the progress of the format.
       The --poll=PT option has been added to control this.

       When  the  --format  option is given without the --wait option then the
       SCSI FORMAT UNIT command is issued with the IMMED bit set which  causes
       the  SCSI  command to return after it has started the format operation.
       The --early  option  will  cause  sg_format  to  exit  at  that  point.
       Otherwise the DEVICE is polled every 60 seconds with TEST UNIT READY or
       REQUEST SENSE commands until it reports an "all clear" (i.e. the format
       operation  has  completed). Normally these polling commands will result
       in a progress indicator (expressed as a percentage) being output to the
       screen.   If  the  user  gets  bored  watching the progress report then
       sg_format process can  be  terminated  (e.g.  with  control-C)  without
       affecting  the  format  operation  which continues. However a target or
       device reset (or a power cycle)  will  probably  cause  the  device  to
       become "format corrupt".

       When  the  --format and --wait options are both given then this utility
       may take a long time to return. In this case care should be  taken  not
       to  send  any  other  SCSI  commands  to the disk as it may not respond
       leaving those commands queued behind the active  format  command.  This
       may  cause  a timeout in the OS driver (in a lot shorter period than 15
       hours applicable to some format operations). This may result in the  OS
       resetting  the  disk  leaving the format operation incomplete. This may
       leave the disk in a "format corrupt" state requiring another format  to
       remedy the situation.

       When the block size (i.e. the number of bytes in each block) is changed
       on a disk two SCSI commands must be sent: a MODE SELECT to  change  the
       block  size  followed  by  a FORMAT command. If the MODE SELECT command
       succeeds and the FORMAT fails then the disk may be in a state that  the
       draft  standard  calls  "format  corrupt".  A  block  descriptor  in  a
       subsequent MODE SENSE will report the requested new block size while  a
       READ  CAPACITY  command will report the existing (i.e. different) block
       size. Alternatively the READ CAPACITY command may fail,  reporting  the
       device  is  not  ready, potentially requiring a format. The solution to
       this situation is to do a format again (and this  time  the  new  block
       size  does  not  have to be given) or change the block size back to the
       original size.

       The SBC-2 standard states that the block count can be set back  to  the
       manufacturer's   maximum  recommended  value  in  a  format  or  resize
       operation.  This can be done by placing an address  of  0xffffffff  (or
       the  64  bit equivalent) in the appropriate block descriptor field to a
       MODE SELECT command. In signed (two's complement) arithmetic that value
       corresponds  to  the  manufacturer's  maximum recommended value. To see
       exactly which SCSI commands are being executed  and  parameters  passed
       add the "-vvv" option to the sg_format command line.

       Short  stroking  is  a technique to trade off capacity for performance.
       Rotating disk performance is usually highest on the outer tracks  (i.e.
       lower logical block addresses) so by resizing or reformatting a disk to
       a smaller capacity, average performance will usually be increased.

       Other utilities may be useful in finding  information  associated  with
       formatting.   These   include   sg_inq(8)  to  fetch  standard  INQUIRY
       information (e.g. the PROTECT bit) and to fetch  the  EXTENDED  INQUIRY
       VPD page (e.g. RTO and GRD_CHK bits). The sdparm(8) utility can be used
       to access and potentially change the now obsolete format mode page.

       scsiformat is another utility available for formatting SCSI disks  with
       Linux.  It  dates  from 1997 (most recent update) and may be useful for
       disks whose firmware is of that vintage.

       The COUNT numeric argument may include a multiplicative  suffix  or  be
       given  in  hexadecimal.  See  the  "NUMERIC  ARGUMENTS"  section in the
       sg3_utils(8) man page.

       The SCSI SANITIZE command was introduced in SBC-3 revision  27.  It  is
       closely related to the ATA sanitize disk feature set and can be used to
       remove all existing data from a disk. Sanitize is  more  likely  to  be
       implemented  on  modern  disks  (including  SSDs)  than  FORMAT  UNIT's
       security initialization feature (see the --security option) and in some
       cases much faster.

EXAMPLES

       These  examples  use  Linux  device names. For suitable device names in
       other supported Operating Systems see the sg3_utils(8) man page.

       In the first example below simply find out the existing block count and
       size  derived  from  two  sources:  a block descriptor in a MODE SELECT
       command response and from the response of a READ CAPACITY commands.  No
       changes are made:

          sg_format /dev/sdm

       Now  a  simple  format,  leaving  the block count and size as they were
       previously.  The FORMAT UNIT command is executed in IMMED mode and  the
       device is polled every 60 seconds to print out a progress indication:

          sg_format --format /dev/sdm

       Now the same format, but waiting (passively) until the format operation
       is complete:

          sg_format --format --wait /dev/sdm

       Next is a format in which the block size is changed to  520  bytes  and
       the  block  count  is set to the manufacturer's maximum value (for that
       block size). Note, not all disks support changing the block size:

          sg_format --format --size=520 /dev/sdm

       Now a resize operation so that only the first 0x10000 (65536) blocks on
       a disk are accessible. The remaining blocks remain unaltered.

          sg_format --resize --count=0x10000 /dev/sdm

       Now resize the disk back to its normal (maximum) block count:

          sg_format --resize --count=-1 /dev/sdm

       Format with type 1 protection:

          sg_format --format --fmtpinfo=2 /dev/sdm

       Format with type 3 protection:

          sg_format --format --fmtpinfo=3 --pfu /dev/sdm

EXIT STATUS

       The  exit status of sg_format is 0 when it is successful. Otherwise see
       the sg3_utils(8) man page. Unless the --wait option is given, the  exit
       status  may  not reflect the success of otherwise of the format.  Using
       sg_turs(8) and sg_readcap(8) after the format operation may be wise.

AUTHORS

       Written by Grant Grundler, James Bottomley and Douglas Gilbert.

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright (C) 2005-2012 Grant Grundler,  James  Bottomley  and  Douglas
       Gilbert
       This  software  is  distributed  under  the  GPL version 2. There is NO
       warranty; not even for MERCHANTABILITY  or  FITNESS  FOR  A  PARTICULAR
       PURPOSE.

SEE ALSO

       sg_turs(8),    sg_requests(8),   sg_inq(8),   sg_modes(8),   sg_vpd(8),
       sg_reassign(8), sg_readcap(8),  sg3_utils(8),  sg_sanitize(8)  [all  in
       sg3_utils], sdparm(8), scsiformat (old), hdparm(8)