**********************************************************************
* IMPORTANT!  This patch is to be used ONLY in conjunction with Jeff *
*             Vavasour's CoCo 3 Emulator.                            *
**********************************************************************

EXTERNAL.EXE is a program that will patch the COCO3.ROM used by the
TRS-80 CoCo 3 Emulator version 1.60.  To apply the patch, copy 
EXTERNAL.EXE into the same directory as the CoCo 3 Emulator and its
COCO3.ROM file, then run EXTERNAL.EXE.

Once the patch has been applied, Disk Extended Colour BASIC will have
several enhancements:

* Descriptive error messages.

  Instead of ?SN ERROR, you'll see ?SYNTAX ERROR

* DIRX
  DIRX string$

  DIRX will display a list of files in the current default MS-DOS directory,
  or specify a parameter to search for specific files.  Wildcards are
  supported.  (e.g. use DIRX"*.BAS" to see all .BAS files in the default
  MS-DOS directory.)

* DRIVEX string$

  Change the default directory to string$.  Use "/" in place of "\" to
  specify multiple directories.  (e.g. use DRIVEX"/TRS80/COCO3" to change
  to the directory \TRS80\COCO3 on the default drive.  DRIVEX"E:/TRS80/COCO3"
  changes to the directory \TRS80\COCO3 on drive E:.)

* RUNX, LOADX, LOADXM, SAVEX, SAVEXM, KILLX

  These are equivalent to the traditional BASIC load/save/kill commands,
  except they access files in the default MS-DOS directory instead of the
  CoCo virtual disks.

* DOSX

  Exit the emulator.


Known problems:

* If your program used a statement like LOADX$ it will now be interpreted
  as LOADX $, which is a syntax error.  To fix this, add a space after LOAD
  so that it reads LOAD X$.

* The patch uses the space occupied by the Three Musketeers.  You won't be
  able to see them if the patch is applied.  (To see them in the emulator
  using the normal COCO3.ROM, hold down CTRL+ALT+ESC+F10 in that order.)

* The default directory set by DRIVEX can change if you call up one of the
  emulator menus that display directories.  (i.e. if you press F2, F3, or
  F4 for the virtual-disk/snapshot/virtual-cassette menus, this can change
  the default directory.)  If you are using the MS-DOS extensions inside a
  program, it is best to issue a DRIVEX immediately prior to the LOADX, etc.

* Testing has only been conducted on DECB version 1.1.  It is unknown at this
  time whether this patch will function correctly on DECB version 1.0.


Removing the patch:

If you wish to remove the patch, use the following MS-DOS commands:

MOVE COCO3ROM.BAK COCO3.ROM

(For older versions of MS-DOS, replace MOVE with COPY.)

- - -

This patch is distributed as-is, without warranty.  Visit

http://www.vavasour.ca/jeff/trs80.html#coco3

for more details on this patch and the CoCo 3 Emulator.
