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FORMAT(8V)                                                          FORMAT(8V)



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 man-
       ual 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 appro-
       priate headers and a test pattern and then checking the sector by read-
       ing 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 greater than 5 bits  in  length
       is  detected  (such  errors  are  indicated  as  ``ECC'' in the summary
       printed upon completing 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.  Format may be used on any UNIBUS or MASSBUS
       drive supported by the up and hp device drivers which uses 4-byte head-
       ers (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 burnin," which
       makes 46 passes using different patterns.  Using this  option,  sectors
       with  any  errors  of any size are marked bad.  This test runs for many
       hours, depending on the disk and processor.

       Each time format is run a completely new bad sector table is  generated
       based  on errors encountered while formatting.  The device driver, how-
       ever, 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.

       Formatting a 400 megabyte disk on a  MASSBUS  disk  controller  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 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  for-
       matted; while ``up(10,0)'' indicates UNIBUS drive 2 on UNIBUS adaptor 1
       should be formatted.

       Before each formatting attempt, format prompts the user in case  debug-
       ging  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  all sectors with uncorrectable media errors are remapped.  If a
       drive develops uncorrectable defects after formatting, the program bad-
       sect(8) must be used.

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.  Boldface 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
            Available test patterns are:
                      1 - (f00f) rh750 worst case
                      2 - (ec6d) media worst case
                      3 - (a5a5) alternating 1's and 0's
                      4 - (ffff) Severe burnin (takes several hours)
            Pattern (one of the above, other to restart)? 2
            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:
            Write check: 4
            Bad sector: 0
            ECC: 0
            Skip sector: 0
            Total of 4 hard errors found.
            Writing bad sector table at block 808271
            (808271 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 format-
       ting.  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

       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  run-
       ning UNIX system.

       It  should  be  possible  to  define more precisely what a ``hard ECC''
       error is; e.g. the maximum unacceptable ECC width.



4th Berkeley Distribution      25 February 1983                     FORMAT(8V)