L S C 0 M P

Compares  two  files,  parts of files,  diskettes,  or  parts  of
diskettes for a character for character match. The proper  syntax
is :


     LSCOMP filespec1 TO filespec2 (parm,parm,...)
     LSCOMP :drivel TO :drive2 (parm,parm,...)
     
     The allowable parameters are
     
     REC=      Starting record number of the filespecs at
               which the compare will begin (default is 0).
     
     NUM=      Number of records of a filespec or sectors of
               a disk to compare.
     
     ALL       Display each non-matching byte.
     
     PRINT     Send display to *PR as well as *DO.
     
     CYL=      Cylinder at which to start compare between
               two drives (default is 0).
     
     SEC=      Starting sector of a diskette to compare
               (default is 0).
     
     Abbr: REC=R, NUM=N, ALL=A, PRINT=P, CYL=C, SEC=S


This  utility  compares  two files or  two  entire  diskettes  to
determine  whether  or  not the information  in  or  on  them  is
identical. It is usually performed after a BACKUP or  a  COPY  to
determine the validity of the data.

Observe the following command and output that is generated:

  LSCOMP MAY/DAT:3 :4

  MAY/DAT:3      contains  17 sectors, EOF offset = 70
  MAY/DAT:4      contains  17 sectors, EOF offset = 70

Notice  that  the second filespec was indicated by  a  drivespec.
This  is  the  ONLY  exception to a complete  filespec  which  is
allowed. Since the files proved to be identical, only the  number
of  compared  sectors  followed by the  end-of-file  offset  were
displayed.

In the case of differing files the following would occur:

  LSCOMP FISCAL82/DAT:3 FISCAL82/DAT:4 (R=4)

  Posn= X'0005,00  FISCAL82/DAT:3 = X'20,  FISCAL82/DAT:4 = X'00
      29 bytes did not match.
  Posn= X'0005,B0  FISCAL82/DAT:3 = X'54,  FISCAL82/DAT:4 = X'00
      32 bytes did not match.

  FISCAL82/DAT:3 contains  18 sectors, EOF offset = 100
  FISCAL82/DAT:4 contains  18 sectors, EOF offset = 100

The  display  shows  the  record number of  a  discrepant  sector
followed by the relative byte, and the contents of that  byte  in
each  filespec.  The  second line displays the  total  number  of
subsequent  bytes  which do not match. If the ALL  parameter  had
been  specified,  each  of the sixty-one bytes  would  have  been
displayed  in  the  first format. Since  the  parameter  R=4  was
specified, the compare began at record 4.

To  compare  one  disk to another use drive  numbers  instead  of
filespecs.  The  starting  cylinder  and  sector  number  may  be
specified  either  in X'00' format or as a decimal  integer.  The
number of contiguous sectors to compare may also be specified  by
using the NUM= parameter.

Unlike  file  to file comparisons, the disk to disk compare  will
display  the  currently accessed sector relative to  the  current
cylinder.  As  much  information as possible will  be  read  into
memory  from  the  source  drive  (the  first  drivespec).   This
information  will then be compared to the destination  drive.  If
discrepant  bytes are detected the following will appear  on  the
video:

  Cyl MOD, Sec X'00, Byte X'00, Drive 2 = X'6D, Drive 3 = X'31
  3078 bytes did not match.

If  the ALL parameter had been specified then each different byte
would display in the first line format. To send the output to the
printer as well as the video, specify the PRINT parameter.