🚀 go-pugleaf

kevin@wicat.com (Kevin Vigor) writes:

>boh@fraser.sfu.ca (Changhao Boh) writes:

>>Hi, I am wondering about programming a serial communication programme in DOS
>>but would like to make it "OS/2 aware".  Thus I have the following questions.

>>   1.  Is there a way to detect if a programme is operation in OS/2 2.0's
>>       dos box ?

>A question I'd like an answer to myself; however, at the moment, I am just 
>checking the DOS version; if the major version is 20 or higher, I assume
>I'm dealing with OS/2 2.x or better.

>>   2.  Is there a way a programme, running in OS/2 2.0's DOS box, can release
>>       clock cycles to OS/2 ?

>Call interrupt 2F (hex) with AX set to 1680 (hex). The call returns with
>AL set to zero on sucess and 80 on failure. N.B.: this same call works
>in a Windows 3.x DOS box and under DPMI.

If the clock cycles are already released, why a return value in AL ?
Hmm... Writting this, I've just answered my own question, AL is returned
when release failed... {:-]

>>   3.  What happens when a programme hooks onto the serial communication
>>       inturrupt as provided by DOS INT 21h ? Will a interrupt driven
>>       serial communication driver written this way be efficient in the
>>       DOS box of OS/2 ?

>Don't know, but as it's completely inefficient under DOS, I doubt it'll be
>any better under OS/2 DOS box.

Why is this ineffecient under DOS ?  I though making a communication driver
interrupt driven is the most effecient way of coding, regardless of OS.

I've another question,

  Can a programme in DOS box utilises the services provided by VCOM.SYS and
  COM.SYS ?

>-- 
>		Peace & PopTarts, 
>			Kevin
>Email to the reply address will almost certainly bounce; use
>72500.3705@compuserve.com

Thanks for replying.

Good Health.

Changhao
boh@sfu.ca