OS/2 vs Win3.1

Bert Thomas bert at brothom.nl
Sat Oct 15 03:15:19 CDT 2005


Allison wrote:
>   How does OS/2 warp V3 compare to other PC OSs like CDR Concurrnet386 or
>   win3.1?

I don't know anything about Concurrent386, but comparing OS/2 Warp with 
win 3.1 is like comparing pigs with streetlights.

Win3.1 is a graphical shell around DOS. To overcome DOS' memory 
limitations is uses some more advanced techniques of the processor, such 
as protected mode. However, win3.1 programs are 16-bit. Win3.1 itself is 
16 bit. Win 3.1 only allows cooperative multitasking. That means that a 
another program can only get control if the running program gives it up. 
This is a very short summery of Win3.1

OS/2 2.0 and higher are 32-bit operating systems. However, compatibility 
with older OS/2 applications was considered very important and therefore 
parts of the kernel and all device drivers are mainly 16 bit. Only 
recently some 32-bit device drivers were written.

OS/2 has its own graphical subsystem - a very advanced one. It can run 
DOS programs in 'virtual dos machines' or VDM. A special mode of the 386 
processor allows a task to act as if it where a real mode task. Anything 
that task does can trap the processor and thus can be handled by 
exception handlers. OS/2 is very strong is this area.

OS/2 has its own file system with some special features like "extended 
attributes".

OS/2 has dynamic priorities for tasks, that makes it more responsive. 
For example, a task that has focus in the GUI is slightly raised in 
priority. Or when a background task was blocking for something it might 
receive a slight priority boost when that something becomes available.

OS/2's time critical priority is handled "soft realtime". I've used OS/2 
in the past for process control, dosing in particular. For such 
applications realtime behaviour is very important as a lattency of 1 sec 
or more is disasterous for the product being manufactered.

I can go on and on, but if you want to know more let me know and I write 
it down later on.

Regards,
Bert



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