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DSKRAT.DOC -- Changes from V14(23) to V14A(24)
April 1983































THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY ONLY BE USED 
OR COPIED IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.

COPYRIGHT (c) DIGITAL EQUIPMENT CORPORATION 1974,1976,1977,1983,1986.
ALL RIGHTS RESERVED.

DSR14A.DOC                                                      Page 2


DSKRAT.DOC -- Changes from 14(23) to 14A(24)
April 1983



1.0  SUMMARY

DSKRAT is a disk damage assessment program which lets a user  see  the
inconsistencies in the disk data base.

The only change in version 14A(24) is one to correct a bug whereby  an
incorrect  LSTBLK  file  was  written  if the last bit in the last SAT
block on the first unit was on  a  word  boundary.   Deletion  of  the
errant LSTBLK file resulted in a BAZ stopcode.



2.0  EXTERNAL CHANGES

None.



3.0  KNOWN BUGS AND DEFICIENCIES

If DSKRAT generates LSTBLK.XXX files, and also has to make a 2nd  pass
on  the disk (due to multiply used clusters), then it will incorrectly
report the blocks in LSTBLK.XXX as used bit not marked in SAT.



4.0  INSTALLATION INSTRUCTIONS

     .LOAD DSKRAT
     .SAVE DSKRAT

DSR14A.DOC                                                      Page 3


5.0  INTERNAL CHANGES

None.



6.0  SUGGESTIONS

It is strongly recommended that DSKRAT  be  run  twice  if  lost-block
recovery is being done.  The output of the 2nd run should be inspected
before the LSTBLK.* files are deleted.

For fastest processing,  it  is  strongly  suggested  that  DSKRAT  be
enabled  for  super  I/O.   This  can  be  accomplished  by depositing
location 140 non-zero.



[End of DSR14A.DOC]

[DSR14.DOC is appended as an integral part of DSR14A.DOC] 
DSKRAT.DOC -- Changes from V14(22) to V14(23)
February 1977






























Copyright (C) 1974,1976,1977
Digital Equipment Corporation, Maynard, Mass.

DSR14A.DOC                                                      Page 4


This software is furnished under a license for use only  on  a  single
computer system and may be copied only with the inclusion of the above
copyright notice.  This software, or any other copies thereof, may not
be provided or otherwise made available to any other person except for
use on such system and to one  who  agrees  to  these  license  terms.
Title  to  and  ownership of the software shall at all times remain in
DEC.

The information in this software is subject to change  without  notice
and  should  not  be  construed  as  a commitment by Digital Equipment
Corporation.

DEC assumes no responsibility  for  the  use  or  reliability  of  its
software on equipment which is not supplied by DEC.

DSR14.DOC                                                       Page 5


DSKRAT.DOC -- Changes from 14(22) to 14(23)
February 1977



1.0  SUMMARY

DSKRAT is a disk damage assessment program which lets a user  see  the
inconsistencies in the disk data base.

The major change in  14(23)  is  to  modify  the  lost-block  recovery
algorithm.   Lost  blocks  which are marked as bad in the BAT block of
the file structure are now not returned for use as  available  blocks.
DSKRAT  runs under all 5- series and 6- series monitors.  DSKRAT, with
its lost-block recovery code, has been run  in-house  so  successfully
that  the  public disk structures on the development machines have not
been refreshed for over a year.



2.0  EXTERNAL CHANGES

After running DSKRAT, recovering lost blocks, running DSKRAT again may
still  show  some  lost blocks (marked in SAT, but in no file).  These
blocks are marked as bad in the BAT block of  the  file  structure  so
they are not returned as recovered blocks.

DSKRAT reads RIBs itself, and checks most  of  the  RIB  in  the  same
manner  as  the monitor.  In order to ensure that the monitor can read
the file it also does a LOOKUP.  DSKRAT runs  approximately  twice  as
fast if this LOOKUP is not done.  If location 140 in DSKRAT (symbol is
DOLOOK) is set non-0 then DSKRAT will not do  the  LOOKUP.   The  only
check  which  the  monitor  makes which DSKRAT does not make is to see
that the block number of the directory  which  contains  the  file  is
correct (.RBUFD).

DSKRAT will now do Lost-Block recovery if SCHED 10 is  in  effect  (no
remote terminals are usable)



3.0  KNOWN BUGS AND DEFICIENCIES

If DSKRAT generates LSTBLK.XXX files, and also has to make a 2nd  pass
on  the disk (due to multiply used clusters), then it will incorrectly
report the blocks in LSTBLK.XXX as used bit not marked in SAT.



4.0  INSTALLATION INSTRUCTIONS

     LOAD DSKRAT
     SAVE DSKRAT

DSR14.DOC                                                       Page 6


5.0  INTERNAL CHANGES

The push down list has been made longer so that DSKRAT can now  handle
SFD's  nested  to  a level of 5 without PDL overflows.  A bug has been
fixed which caused DSKRAT to read the wrong block as a SAT block under
some conditions.



6.0  SUGGESTIONS

It is strongly recommended that DSKRAT  be  run  twice  if  lost-block
recovery is being done.  The output of the 2nd run should be inspected
before the LSTBLK.* files are deleted.



[End of DSR14.DOC]

[DSR12.DOC is appended as an integral part of DSR14.DOC]

DSR12.DOC                                                       Page 7


DSKRAT.DOC -- Changes from V11(10) to V12(11)
April 1974



1.0  SUMMARY

Version 12(11) is now consistent with JOBDAT V427(440).

Version 11(10) contains a routine to recover lost blocks on single  or
multi-structure units.



2.0  EXTERNAL CHANGES

None.



3.0  KNOWN BUGS AND DEFICIENCIES

None.



4.0  INSTALLATION INSTRUCTIONS

None.



5.0  INTERNAL CHANGES

Version 11(10) has had code added to implement the  recovery  of  lost
blocks due to crashes and/or software errors.



6.0  DATE-75 PROPOSAL

DSKRAT needs no modifications in order  to  comply  with  the  DATE-75
standard.



[End of DSR12.DOC]