          ZIPFILE DUPLICATE CHECKING SYSTEM (ZDCS)  Ver. 2.0
              Copyright (C) 1991, 1992  Michael W. Cocke
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MERGING TWO DATABASES

Each ZDCS database consists of two files.  They both have the same
filename, but one has the extension .NDX and the other has the
extension .DAT.  When you are running ZDCS on a BBS, the two files are
always named ZDCS.NDX and ZDCS.DAT.

To merge two databases, you need the database merge utility
ZDCSDBMG.EXE and the *.DAT file from each database.  Make sure that
one of the two database files is named ZDCS.DAT.  (This is usually
your existing database.)  The other database file can have any valid
filename before the .DAT extension.  (This is often a pre-built CD-ROM
database that you want to add to your system.)  It doesn't matter
which .DAT file is named ZDCS.DAT, because both will be combined to
create a new database.

To merge these two databases into one new database, create a temporary
working directory and put copies of the following in it:

1.   your existing database, ZDCS.DAT file only
2.   the *.DAT database you wish to merge into your existing database
3.   the ZDCSDBMG.EXE database merge program

Check your CONFIG.SYS file and make sure that you have FCBS=32,32.
ZDCSDBMG.EXE absolutely =requires= this.

Now run the merge program on the new database by typing

     ZDCSDBMG <database filename>

at the command prompt.  Don't use the .DAT extension when you specify
the database name.  The result will be a new N-ZDCS.DAT file and its
accompanying N-ZDCS.NDX file.  To use them, you'll need to rename them
to ZDCS.DAT and ZDCS.NDX and then copy the two new files over the old
ones in your ZDCS directory.  That's it!  (Well, you might want to
clean out your temporary working directory.)

The improved database merge program ZDCSDBMG.EXE eliminates the need
for the *.NDX files when you merge a database.  The new N-ZDCS.NDX
file is generated right from the newly merged database.  This means
that the pre-built databases available on The Hacker Central can now
be smaller, which cuts down on storage requirements and transfer time,
saving us all a little money.


RECREATING THE *.NDX FILE

If for some reason you decide you do want to recreate the .NDX file
for a .DAT file you have, you'll need to go back to the database
reporting utility ZDCSDR.EXE to do that.  Here are the steps to
follow:

1. Rename the *.DAT file to ZDCS.DAT.

2. Create a temporary working directory on a local disk drive.  Copy
   the newly renamed ZDCS.DAT file into that working directory.
   (Make sure that you have enough storage space available for the
   final pair of files.)

3. Put copies of your ZDCS.CFG file and the ZDCSDR.EXE program in
   your temporary working directory.  This minimizes the chances that
   you'll get your regular ZDCS configuration file mixed up with the
   one you're about to modify.

4. Change the second line of ZDCS.CFG so that it points to your
   working directory.  Check your CONFIG.SYS file and make sure that
   you have FCBS=32,32.  ZDCSDR.EXE and ZDCSDBMG.EXE absolutely
   =require= this.

5. To start the process, type ZDCSDR S at the command prompt.  You
   need to do this while you are in the working directory.

When ZDCSDR has finished running, you will find the recreated ZDCS.NDX
file in your working directory, along with the original ZDCS.DAT file.
