I have now successfully built overlayed DOS executables using Watcom 10.6
under Windows XP Service Pack 2:

============================================================================
C:\dv\s3\exe\max>dir
 Volume in drive C has no label.
 Volume Serial Number is C097-5E23

 Directory of C:\dv\s3\exe\max

06/02/2010  01:06 AM              .
06/02/2010  01:06 AM              ..
06/02/2010  01:06 AM           553,091 max.exe
06/02/2010  01:06 AM           392,912 max.ovl
06/02/2010  01:06 AM         1,195,146 maxd.exe
               3 File(s)      2,141,149 bytes
               2 Dir(s)  25,853,984,768 bytes free

C:\dv\s3\exe\max>
============================================================================

Preliminary testing shows that it works. Online games also work (via NetFoss):

============================================================================
+ 06 Feb 01:07:12 MAX  Begin, v3.02-1 (task=1)
  06 Feb 01:07:12 MAX  Your Public Access Network

Mvan Le (Y,n)? y

Password:
============================================================================

The NT build however doesn't work very well. The 10.6 Wlinker complains
about undefined references ...

============================================================================
...
...
...
cd comdll && c:\dv\cvs\dmaken.exe
wcc386 /dNT -bt=NT /j/zp1/4/fp3/onmaxte100 /Fo=W3n\ntcomm.obj /bd .\ntcomm.c
wcc386 /dNT -bt=NT /j/zp1/4/fp3/onmaxte100 /Fo=W3n\ntcommdl.obj /bd .\ntcommdl.c
wlink libpath c:\dv\comp\wc15\lib386\nt lib nt,kernel32,user32 {at}ntcomm
WATCOM Linker Version 10.6
Copyright by WATCOM International Corp. 1985, 1996. All rights reserved.
WATCOM is a trademark of WATCOM International Corp.
Warning(1038): file ntcomm.lnk: line(1): DEBUG directive appears after object files
Warning(1028): _ComOpenHandle is an undefined reference
Warning(1028): _ComOpen is an undefined reference
Warning(1028): _ComClose is an undefined reference
Warning(1028): _ComIsOnline is an undefined reference
Warning(1028): _ComWrite is an undefined reference
Warning(1028): _ComRead is an undefined reference
Warning(1028): _ComGetc is an undefined reference
Warning(1028): _ComPeek is an undefined reference
Warning(1028): _ComPutc is an undefined reference
Warning(1028): _ComRxWait is an undefined reference
Warning(1028): _ComTxWait is an undefined reference
Warning(1028): _ComInCount is an undefined reference
Warning(1028): _ComOutCount is an undefined reference
Warning(1028): _ComOutSpace is an undefined reference
Warning(1028): _ComPurge is an undefined reference
Warning(1028): _ComGetHandle is an undefined reference
Warning(1028): _ComGetDCB is an undefined reference
Warning(1028): _ComSetDCB is an undefined reference
Warning(1028): _ComSetBaudRate is an undefined reference
Warning(1028): _ComPause is an undefined reference
Warning(1028): _ComResume is an undefined reference
Warning(1028): _ComWatchDog is an undefined reference
Error(2044): exported symbol _ComOpenHandle not found
Error(2044): exported symbol _ComOpen not found
Error(2044): exported symbol _ComClose not found
Error(2044): exported symbol _ComIsOnline not found
Error(2044): exported symbol _ComWrite not found
Error(2044): exported symbol _ComRead not found
Error(2044): exported symbol _ComGetc not found
Error(2044): exported symbol _ComPeek not found
Error(2044): exported symbol _ComPutc not found
Error(2044): exported symbol _ComRxWait not found
Error(2044): exported symbol _ComTxWait not found
Error(2044): exported symbol _ComInCount not found
Error(2044): exported symbol _ComOutCount not found
Error(2044): exported symbol _ComOutSpace not found
Error(2044): exported symbol _ComPurge not found
Error(2044): exported symbol _ComGetHandle not found
Error(2044): exported symbol _ComGetDCB not found
Error(2044): exported symbol _ComSetDCB not found
Error(2044): exported symbol _ComSetBaudRate not found
Error(2044): exported symbol _ComPause not found
Error(2044): exported symbol _ComResume not found
Error(2044): exported symbol _ComWatchDog not found
dmaken.exe:  Error code 129, while making 'c:\dv\s3\dll\ntcomm.dll'
dmaken.exe:  Error code 255, while making 'comdll'
*** make nt Compilation error encountered. Terminating build.
Ended: Sat 06/02/2010 {at} 1:30:41.89

C:\dv\s3>
============================================================================

I can produce NT executables with Watcom 11.0c however there seems to be
some very odd keyboard mapping issues with "maxn.exe" and
"maxnd.exe". None of my input key strokes work or get recognised
properly. For example "Alt-X" in WFC mode says "Junk
character from keyboard": 

+-] Current Activity ]------------------------------------------------------+
]                                                                           ]
]                                                                           ]
]: 06 Feb 02:24:59 MAX  Waiting for caller (event in 170 mins)              ]
]  06 Feb 02:30:54 MAX  Junk character from keyboard                        ]
]  06 Feb 02:30:54 MAX  Junk character from keyboard                        ]
+---------------------------------------------------------------------------+

But I'm happy that I seem to have a working DOS binary :) Atleast now I
have something to start working on.

--- Maximus/2 3.01