


FORMAT(8)                                               FORMAT(8)


NAME
       format - how to format disk packs

DESCRIPTION
       There  are two ways to format disk packs.  The simplest is
       to use the format program.  The alternative is to use  the
       DEC  standard formatting software which operates under the
       DEC diagnostic supervisor.  This manual page describes the
       operation  of  format,  then  concludes  with some remarks
       about using the DEC formatter.

       Format is a standalone program used to  format  and  check
       disks  prior to constructing file systems.  In addition to
       the formatting operation, format records any  bad  sectors
       encountered  according to DEC standard 144.  Formatting is
       performed one track at a time by writing  the  appropriate
       headers and a test pattern and then checking the sector by
       reading and verifying the pattern, using the  controller's
       ECC  for  error  detection.   A sector is marked bad if an
       unrecoverable media error is detected, or if a correctable
       ECC error too many bits in length is detected (such errors
       are indicated as ``ECC'' in the summary printed upon  com-
       pleting  the format operation).  After the entire disk has
       been formatted and checked, the total number of errors are
       reported, any bad sectors and skip sectors are marked, and
       a bad sector forwarding table is written to  the  disk  in
       the  first  five  even numbered sectors of the last track.
       It is also possible to reformat sections of  the  disk  in
       units  of  tracks.   Format  may  be used on any UNIBUS or
       MASSBUS drive supported by the up and  hp  device  drivers
       which uses 4-byte headers (everything except RP's).

       The  test  pattern  used  during  the  media  check may be
       selected from one of: 0xf00f (RH750  worst  case),  0xec6d
       (media  worst case), and 0xa5a5 (alternating 1's and 0's).
       Normally the media worst case pattern is used.

       Format also has an option to perform an  extended  "severe
       burn-in,"  which  makes a number of passes using different
       patterns.  The number of passes can  be  selected  at  run
       time, up to a maximum of 48, with provision for additional
       passes or termination  after  the  preselected  number  of
       passes.   This  test runs for many hours, depending on the
       disk and processor.

       Each time format is run to format an entire disk,  a  com-
       pletely  new bad sector table is generated based on errors
       encountered while formatting.  The device driver, however,
       will  always attempt to read any existing bad sector table
       when the device is first opened.  Thus, if a disk pack has
       never  previously  been  formatted,  or has been formatted
       with different sectoring,  five  error  messages  will  be
       printed  when  the  driver attempts to read the bad sector
       table; these diagnostics should be ignored.



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FORMAT(8)                                               FORMAT(8)


       Formatting a 400 megabyte disk  on  a  MASSBUS  disk  con-
       troller  usually  takes about 20 minutes.  Formatting on a
       UNIBUS disk controller takes  significantly  longer.   For
       every hundredth cylinder formatted format prints a message
       indicating the current cylinder  being  formatted.   (This
       message is just to reassure people that nothing is amiss.)

       Format uses the standard notation of  the  standalone  I/O
       library  in  identifying a drive to be formatted.  A drive
       is specified as zz(x,y), where zz refers to the controller
       type (either hp or up), x is the unit number of the drive;
       8 times the UNIBUS or  MASSBUS  adaptor  number  plus  the
       MASSBUS drive number or UNIBUS drive unit number; and y is
       the file system partition on drive x (this  should  always
       be 0).  For example, ``hp(1,0)'' indicates that drive 1 on
       MASSBUS adaptor 0 should be formatted; while  ``up(10,0)''
       indicates  that  UNIBUS drive 2 on UNIBUS adaptor 1 should
       be formatted.

       Before each formatting attempt, format prompts the user in
       case debugging should be enabled in the appropriate device
       driver.  A carriage return disables debugging information.

       Format should be used prior to building file systems (with
       newfs(8)) to insure that all  sectors  with  uncorrectable
       media  errors  are  remapped.   If a drive develops uncor-
       rectable defects after  formatting,  either  bad144(8)  or
       badsect(8) should be able to avoid the bad sectors.

EXAMPLE
       A  sample  run  of format is shown below.  In this example
       (using a VAX-11/780), format is loaded  from  the  console
       floppy;  on  an 11/750 format will be loaded from the root
       file system with boot(8) following a "B/3" command.  Bold-
       face  means  user input.  As usual, ``#'' and ``@'' may be
       used to edit input.

            >>>L FORMAT
                      LOAD DONE, 00004400 BYTES LOADED
            >>>S 2
            Disk format/check utility

            Enable debugging (0=none, 1=bse, 2=ecc, 3=bse+ecc)? 0
            Device to format? hp(8,0)
            (error messages may occur as old bad sector table is read)
            Formatting drive hp0 on adaptor 1: verify (yes/no)? yes
            Device data: #cylinders=842, #tracks=20, #sectors=48
            Starting cylinder (0):
            Starting track (0):
            Ending cylinder (841):
            Ending track (19):
            Available test patterns are:
                      1 - (f00f) RH750 worst case
                      2 - (ec6d) media worst case



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FORMAT(8)                                               FORMAT(8)


                      3 - (a5a5) alternating 1's and 0's
                      4 - (ffff) Severe burnin (up to 48 passes)
            Pattern (one of the above, other to restart)? 2
            Maximum number of bit errors to allow for soft ECC (3):
            Start formatting...make sure the drive is online
             ...
            (soft ecc's and other errors are reported as they occur)
             ...
            (if 4 write check errors were found, the program terminates like this...)
             ...
            Errors:
            Bad sector: 0
            Write check: 4
            Hard ECC: 0
            Other hard: 0
            Marked bad: 0
            Skipped: 0
            Total of 4 hard errors revectored.
            Writing bad sector table at block 808272
            (808272 is the block # of the first block in the bad sector table)
            Done
            (...program restarts to allow formatting other disks)
            (...to abort halt machine with ^P)


DIAGNOSTICS
       The diagnostics are intended to be self explanatory.

USING DEC SOFTWARE TO FORMAT
       Warning:  These instructions are for  people  with  11/780
       CPU's.   The  steps  needed for 11/750 or 11/730 cpu's are
       similar, but not covered in detail here.

       The formatting procedures are different for each  type  of
       disk.   Listed  here  are  the  formatting  procedures for
       RK07's, RP0X, and RM0X disks.

       You should shut down UNIX and halt the machine to  do  any
       disk  formatting.   Make  certain  you put in the pack you
       want formatted.  It is also a good idea to  spin  down  or
       write  protect the disks you don't want to format, just in
       case.

       Formatting an RK07.   Load  the  console  floppy  labeled,
       "RX11  VAX  DSK  LD DEV #1" in the console disk drive, and
       type the following commands:
              >>>BOOT
              DIAGNOSTIC SUPERVISOR.  ZZ-ESSAA-X5.0-119  23-JAN-1980 12:44:40.03
              DS>ATTACH DW780 SBI DW0 3 5
              DS>ATTACH RK611 DMA
              DS>ATTACH RK07 DW0 DMA0
              DS>SELECT DMA0
              DS>LOAD EVRAC
              DS>START/SEC:PACKINIT



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FORMAT(8)                                               FORMAT(8)


       Formatting an RP0X.  Follow the  above  procedures  except
       that the ATTACH and SELECT lines should read:
              DS>ATTACH RH780 SBI RH0 8 5
              DS>ATTACH RP0X RH0 DBA0(RP0X is, e.g. RP06)
              DS>SELECT DBA0

       This  is for drive 0 on mba0; use 9 instead of 8 for mba1,
       etc.

       Formatting an RM0X.  Follow the  above  procedures  except
       that the ATTACH and SELECT lines should read:
              DS>ATTACH RH780 SBI RH0 8 5
              DS>ATTACH RM0X RH0 DRA0
              DS>SELECT DRA0

       Don't  forget  to put your UNIX console floppy back in the
       floppy disk drive.

SEE ALSO
       bad144(8), badsect(8), newfs(8)

BUGS
       An equivalent facility should be available which  operates
       under a running UNIX system.

       It should be possible to reformat or verify part or all of
       a disk, then update the existing bad sector table.






























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