🚀 go-pugleaf

In article <PAS.90Mar1120125@saffron.lcs.mit.edu> pas@lcs.mit.edu (Paul A. Selkirk) writes:
>
>Does anyone know of a bulletproof way for a TSR to tell whether DOS (assume
>2.x or 3.x) is idling in the command interpreter, or executing a program?
>
>I have determined, through much pain and disassembly, that DOS uses service
>0A (buffered string input) to get the next command, but other programs use that
>as well.  I can get by on this knowledge, but I would prefer something a little
>more certain.
>
>For the record, I am writing a screen-saver TSR that will only trigger when DOS
>is idling.  There are dozens of screen-savers, but I need one that won't kill
>a lengthy graphics program.  (Ever try generating the Mandelbrot set on a 4.77 
>MHz XT with no FPU?  I thought so.)
>
>Any leads will be duly appreciated.
>
>				paul

How about a way of turning screen saver on and off instead.  You can have
an interupt which turns screen saver on and off then write a utility which
calls the interupt which you can run before your program.  You can also
have a keyboard hook to turn it on and off asynchronous to the system state.
In cases where you have access to source code you can turn off the saver
within a program just for the parts where this is important.  I'd suggest
something like the following

    AH = 0    Turns off screen saver
    AH = 1    Turns on screen saver
    AH = FF   Returns 1234H or something unique to determine presence.

I would have it also return the current active state so that programs
could restore the system when necessary.

-- 
D'Arcy J.M. Cain (darcy@druid)     |   Thank goodness we don't get all 
D'Arcy Cain Consulting             |   the government we pay for.
West Hill, Ontario, Canada         |
(416) 281-6094                     |