ZW-DOS SOFTWARE NOTES 

                       (c) Ya-Gui Wei 1992

  ZW-DOS seeks to simulate a text-mode screen that is Chinese-compatible
using the graphic capabilities of the various video adaptors. Since
the graphic capabilities of the video systems vary, it is not always
possible to simulate all the text-mode features completely, -- this
results in some visual peculiarities. The incomplete simulation some-
times affects program execution, therefore incompatibilities. Sometimes,
due to programmer inaptitude or oversight, the computer is not doing
what the programmer wanted it to do, these are bugs.

  This file is intended to document the various peculiarities of
ZW-DOS that the user needs to be aware of.
   
  (1) Visual peculiarities due to incomplete simulation of text 
mode. Note: These peculiarities occur only when the screen display
is in Chinese mode.  In ASCII mode, you should not see any of 
these.

 a. ZWEGA/ZWVGA:  The EGA and VGA versions of ZWDOS have
    the most complete simulation of the text modes. Character 
    color and intensity are well-simulated. Yet some of the
    EGA/VGA features are no longer supported:
    - Loading of alternate ASCII text fonts are no longer 
      supported. The default system fonts are always used.
    - Switching of the screen to 43-line mode (or anything
      other than a 80x25 dimension) is no longer supported.
    - Blinking characters are no longer supported -- they will
      appear with a high-intensity background color instead.

 b. Hercules Monochrome version:  The Hercules version simulates 
    the original monochrome character attributes such as 
    invisibility, underscore, and reversed vido. Yet:
    - Blinking characters are no longer supported. They appear
      the same as regular characters.
    - There will be no visual difference between low-intensity
      and high-intensity attributes.
    - Control of cursor size is not implemented. 

 c. CGA version (including CGA version for AT&T laptop 640x400 
    mode): The color capabilities of these adaptors in their 
    graphic mode is pitiful (so is the resolution of the CGA 
    adaptor). The programmer has done what he can under the 
    circumstances, yet the simulation of text mode is quite 
    unsatisfactory.
    - Colors, intensity difference, and blinking of characters
      are no longer supported. All characters are in black-
      and white and with the same intensity. Those characters
      with a background color value higher than the foreground
      value will appear as reverse video.
    - Direct reading of screen buffer content is no longer
      supported. Any programs that try to read, copy or scroll
      the screen directly will produce garbage dots on screen.
      This can be fixed by simply redrawing the screen, if your
      application can do that.
    - Text output to screen occasionally may be lost, resulting
      in non-updating on a few locations of the screen. This too
      can be fixed by redrawing the screen.
    - Control of cursor size and blinking frequency is not 
      supported. The cursor will appear to be blinking very
      fast and this cannot be changed.


  (2) Incompatibilities related to mice:

 a. The CGA and VGA versions:  If you load these versions of ZWDOS
    AFTER you load the mouse driver, the graphic mouse cursor may
    appear when the screen is in Chinese mode. While the graphic 
    mouse cursor is nicer-looking than the text-mode counter-part, 
    it causes trouble with ZWDOS's screen updating. Therefore it is 
    best to load the mouse driver after loading these versions of 
    ZWDOS.

 b. The EGA version:  Don't load the mouse driver when the display
    is in Chinese mode. The mouse driver will be tremendously
    confused about the video configuration and proceeds to crash
    the system.
 
 c. The Hercules version:  There are no known incompatibility with
    mouse drivers.


  (3) Incompatibilities related to graphic applications

  ZWDOS only simulates a Chinese-compatible text mode. It does nothing
with the graphic modes of the video systems. You cannot input or display
Chinese characters with graphic mode applications.


  (4) Running ZWDOS with DESQview/386, Windows 3.0, or OS/2:

  Despite what is said about the multi-tasking capabilities of these
systems, they may still be confused when the screen is switched to
Chinese mode by ZWDOS. Therefore it may be best to load ZWDOS within
a DOS session of these systems, and run that DOS session in full
screen mode at all times. When you are done with ZWDOS, try to make
the screen switch back to ASCII mode before closing that DOS session.


  (5) HZ Codes That Span Multiple Lines

  HZ codes with the opening tilde-brace NOT closed on the same line
may be occasionally not displayed properly -- typically the first few
lines are display in Chinese while the remaining lines are displayed
in ASCII. (Sometimes the opening tilde-brace has been scrolled out
of the screen, which also causes the remaining paragraph not being 
displayed properly.)  When you are entering HZ text, try to close
each tilde-brace pairs on the same line, if at all possible.
  

  (6) Bug List:

    If you discover some bugs or problems with the programs that 
    have not been described in this file, report it to the programmer.
    The programmer will try to fix the bug.  If it is too much
    trouble, the bug will appear in this file in future releases.