Michael Gleason wrote in a message to Keith Thomson:

 MG> Thank you for the reply. I wonder why VIO, KBD, and Mou are
 MG> still 16 bit....

It's something of an internal controversy in IBM.  Originally, IBM had a
grand scheme for OS/2 where it would become a multi-platform microkernel
operating system, something like NT, with the first major non-Intel
platform selected as the PowerPC.  Unfortunately, like NT, it required
enormous system resources and ran very slowly.  All 16-bit facilities in
OS/2, which are mostly there for backward compatibility with OS/2 1.x
anyway, were going to go away.

The Vio, Kbd, and Mou services are also fairly tightly bound to such Intel
platform issues as VGA hardware, and it was planned that 32-bit
replacements would eventually be forthcoming.  Complicating the design
further is the fact that both OS/2 2.x and NT have a common ancestry in
OS/2 1.x -- NT was originally announced as OS/2 3.0 -- and NT supports the
16-bit OS/2 API when running on Intel.  This is an important marketing
issue, since most of the OS/2 1.x systems still in use are running LAN
Manager, for which NT Server is Microsoft's upgrade path, and most LAN
Manager tools and utilities are 16-bit OS/2.  If it actually became easier
to migrate from LAN Manager on 16-bit OS/2 to NT Server than to LAN
Server/Warp Server on 32-bit OS/2, then disaster would ensue.

As the microkernel operating system became later and later, IBM withdrew
much of its support for it.  The product was finally released to be
available on "special request" at the end of 1995, but has
probably sold less than 100 copies.  IBM has technically not abandoned the
product, but everyone assumes that the formal announcement is just a matter
of time.  If that project gets going again, then IBM would probably resume
its work on the 32-bit versions of the Vio, Kbd, and Mou subsystems.  In
the absence of the microkernel operating system, there is no compelling
reason to replace these 16-bit subsystems with 32-bit code.
 
-- Mike


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