DOS ain't dead

> For DOS, there's one screen and one keyboard. That's it.

Firstly as above don't forget MDA which as mentioned earlier. e.g. Turbo Debugger supported 2 monitors at the same time.

> Anything beyond
> that (you see, even a single mouse) must be managed by additional drivers.

Secondly this statement is false (or it depends how you look at things), e.g. when writing BBS software/doors people often used to think in this manner:

Int 10h, Int 16h = input/output method 1
Int 21h = input/output method 2

e.g. code snippet from my megapage BBS door which used ANSI (for color only but didn't actually need it) and didn't require any other drivers at all:


Procedure DoubleWrite(Text2Write:String);

Begin
  If USEANSI then
    Begin
      If SYSOP_is_Chatting then
        Begin
          If Last_Colour=SYSOP_Textcolour then
            Begin
            End
          else
            Begin
              ANSI_Textcolour(SYSOP_Textcolour);
              Textcolor(SYSOP_Textcolour);
            End;
          Last_Colour:=SYSOP_Textcolour;
        End
      else
        Begin
          If Last_Colour=USER_Textcolour then
            Begin
            End
          else
            Begin
              ANSI_Textcolour(USER_Textcolour);
              Textcolor(USER_Textcolour);
            End;
          Last_Colour:=USER_Textcolour;
        End;
    End;
  DisplayString(Text2Write);
  Write(Text2Write);
End;


> In case you're interested, my need would be to use one computer
> simultaneously with two users. I already have two screens, so this special
> mouse/keyboard driver would effectively split up the whole interface as if
> the two sets of screen/mouse/keyboard were two terminals. But without most
> of the software support and hardware required for a real terminal server.
> Anyway, even two mouse cursors without the keyboard splitting are
> useful for our need.

I'm confused about what you're doing. Are you actually running two separate applications on the same computer at the same time, each on a separate monitor? Or is it just one application (something like a teacher/student session), where the same thing appears on both monitors, and you want the "teacher" to have a separate mouse cursor to point with but not necessarily actually do anything (including moving the "students" mouse cursor)?

> I think it is better to say multiple VGA monitors since obviously it has
> for years if you use a mono monitor and VGA at the same time.

But how would DOS use both monitors at the same time, with different content? I'm not aware of any functionality like that.

---
l

> There was also a program (TSR?) called "doorway" I think to
> allow people to convert most DOS programs to be dual headed BBS doors over
> serial, e.g. command.com

Simtel: drwy231.zip 230K DoorWay: Run any pgm as BBS door, drop to DOS 04-Apr-96

However that version came out after I had already started to shut my BBS down (that version talks about a Win95 fix whatever Win95 is....). I also don't remember doorway being shareware. As it is around 15+ years since I last looked at it I can't be sure that it is exactly the same program, but certainly it looks like it is. I do seem to remember using a non-shareware version though (which probably exists then became shareware). Certainly I know it is likely to be on one of my full height SCSI driver/floppy backups in storage.

> As the keyboard is a serial protocol it can be interfaced easily elsewhere
> and just needs an application to support it (not necessarily with a
> driver).

Okay, but you need special hardware (e.g. a converter) for that, to connect two keyboards to the same PS/2 keyboard port. (Also, this will just "merge" the input of all keyboards.)

> I would imagine this depends on how the PC's BIOS provides legacy USB
> support.

Yes. With Bret's USB keyboard driver all the keyboard input will be "merged", but other drivers might only recognize the first keyboard. Windows' drivers probably "merge" two, but I don't remember whether I actually tried that.

> > This means the driver would have to work with specific applications
> [...]

Ah, so this trick was made an ad-hoc interface by people

> There was also a program (TSR?) called "doorway" I think to
> allow people to convert most DOS programs to be dual headed BBS doors over
> serial, e.g. command.com

You would then have the option to run the modified program either with the one input method or the other, and switch between the two, right?

---
l