                                  VDE266.FIX
                                  ----------
                              E. Meyer - 7/30/88


     There is a potentially serious bug in VDE 2.66, which you can easily fix 
by one of two methods: either a patching utility like DDT, SID, or EDFILE, or 
using MLOAD with the HEX overlays supplied below.  Either way, only three 
bytes need to be changed.

METHOD 1.  Patching utility

     Follow the instructions for your utility to change these bytes:

(a) For VDE266.COM:
  
              Address      Old value            Change to
              29B8         22 01 00             CD A7 29

(b) For VDM266.COM:

              Address      Old value            Change to
              29BB         22 01 00             CD AA 29


METHOD 2.  MLOAD

     Choose the appropriate HEX file (for either VDE or VDM) below, write it 
(just two lines) to disk under the name shown, and use the MLOAD utility to 
overlay it on your copy of VDE:

              A>mload vde266.com,vde266fx.hex

          OR  A>mload vdm266.com,vdm266fx.hex


--------VDE266FX.HEX: cut here---------------
:0329B800CDA7297F
:00000001FF
--------VDM266FX.HEX: cut here---------------
:0329BB00CDAA2979
:00000001FF
---------------------------------------------


     The bug involves the code to handle BDOS disk errors, which was modified 
recently (version 2.65) to make VDE compatible with ZCPR3.  Under normal 
circumstances (or CP/M 3.0) there is no problem.  But if you ever get a BDOS 
disk error (empty drive, etc) under CP/M 2.2, VDE does not properly restore 
the BIOS warm boot entry.

     Thanks to Gene Nolan (c/o DHN* RCPM, 215-623-4040), who discovered this 
problem about a week ago and suggested an easy solution.



      ----- Eric Meyer, 427 N. Washington #4, Bloomington IN 47401 -----
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