#OS/2
"And it is very handicapped by its device driver design, which is 16-Bit only
and NOT preemptive multitasking."
Since I haven't written any device drivers in awhile, I'll let a message from
OS2USER forum speak to this point.
" One can put 32-bit code into device drivers nonetheless. After the
required 16-bit data and code segments for the device headers and entry points,
pretty much anything is fair game. We have an OS/2 physical device driver that
uses a flat 32-bit data segment that can exceed 400kB in size, for instance,
and lots of 32-bit code sprinkled throughout.
Virtual device drivers are fully 32-bit. They were introduced with
OS/2 2.0.
PDDs carry the 16-bit architecture of OS/2 1.x, and, many, if not most, OS/2
1.x driver binaries can run just fine under 32-bit versions of OS/2 if
necessary to support custom legacy applications and/or hardware.
Chris Myers
Electronic Project Engineer
Quatech, Inc. "
Those virtual device drivers are also preemptively multitasked…
"Even old Windows 3.1 is a real, 32-Bit preemptive multitasking Kernel on this
level,"
I also really question this statement, as Win 3.1 doesn't ever preemptively
multitask unless you cheat by using an interrupt to do your task switching.
IMHO, not a good idea, is it can crash the system much to easily.
Bob Comer — Cheyenne, WY USA
Team OS/2