
 1. About DOSX

 HX's DOSX is a replacement for the Windows 3.1 DOSX.  It's purpose is to
 use HX's DPMI host HDPMI16 to run Windows 3.1 or WfW 3.11 in standard mode
 with DOS boxes available. This has one big benefit: HDPMI16 doesn't grab
 all of the extended memory, thus allowing other DPMI applications to be
 run in DOS boxes opened inside windows. Furthermore, the windows DOSX
 cannot use more than 512 MB memory, while HDPMI16 has no restriction
 in this regard.


 2. Installation

 - Copy HX's DOSX.EXE to the Win3.1 system directory. It's a good idea
   to first make a backup copy of the original DOSX.EXE.


 3. Running DOSX.EXE

 Starting windows in standard mode will make use of DOSX.EXE:

   WIN /S

 Please note: although DOSX.EXE could be launched directly (type
 SYSTEM\DOSX in the windows directory), this method won't run WSWAP.EXE,
 which is required for task switching in windows standard mode. So if
 windows is started this way one cannot open a DOS box.


 4. Known Problems

 - WfW 3.11's WIN.COM claims that this version cannot be run in standard
   mode. To run it nevertheless in this mode, copy WIN.COM, WSWAP.EXE and
   DSWAP.EXE from Windows 3.1 to the corresponding WfW 3.11 directories and
   start it with "WIN /S".

 - if FreeDOS is used with Windows 3.1, the system might crash when opening
   a DOS box. It may help to load FreeDOS' SHARE.COM, then this problem seems
   to vanish. But be aware that the FreeDOS' SHARE is very limited and won't
   work with MS-DOS.

 - the Windows 3.1 taskswitcher WSWAP.EXE is not aware of XMS v3 (an API to
   access more than 64 MB of extended memory). This may cause problems if an
   application (including HDPMI) is using XMS v3 functions:

    on machines with 64 MB memory or less XMS v3 functions cannot be used
     while WSPAP is loaded. Therefore, to make HDPMI compatible with WSWAP.EXE,
     environment variable HDPMI=64 must be set.

    on machines with memory between 64 MB and 128 MB, HDPMI may use XMS v3
     functions to allocate memory. However, the first 64 MB of XMS memory will
     be allocated by WSWAP, unaccessible for HDPMI until Windows has
     terminated. So it's probably better to also set HDPMI=64 in this
     configuration - this will supply 64 MB for Windows and the rest may be
     used by DOS applications.

    on machines with more than 128 MB memory, setting HDPMI=64 is not
     recommended. HDPMI may then use all XMS memory, except the 64 MB that WSWAP
     has allocated.


 5. How does DOSX work?

 The windows startup procedure in standard mode is:

  - WIN.COM is started (by the user, with commandline parameter "/S")
  - SYSTEM\WSWAP.EXE is launched by WIN.COM
  - SYSTEM\DOSX.EXE is launched by SYSTEM\WSWAP.EXE
  - SYSTEM\KRNL386.EXE is launched by SYSTEM\DOSX.EXE

 HX's DOSX is a simple DOS real-mode application, unlike the Windows DOSX,
 which is the DPMI host used for standard mode. HX's DOSX will first start
 HDPMI16.EXE if no DPMI server is found, then load and run KRNL386.EXE as
 it is done by the original DOSX.


 6. Copyright

 HX's DOSX is free to use for any purpose. Source and binary are released
 to public domain.

 Japheth

