[ILUG] It's illegal, according to the barrister in PC World

[Rick Moen]

Quoting Smelly Pooh (plop at redbrick.dcu.ie):

> I wouldn't consider something a failed fad just because it hasn't hit the
> mainstream, nor would I consider something a good design because it has.
> For example VB is quite big, but its design is terrible, same with PERL.
> Really ingenius designs such as ML or Haskell are still stuck in
> academics.

The difference is that microkernels have been a spectacular failure in
large, well-funded, mainstream projects.  

IBM Workplace OS was going to be the portable, modular successor to
OS/2, running on top of CMU's Mach.  This was one of the doubtful fruits
of the Taligent consortium.  OS/2 and Workplace Shell were going to be
one of numerous "personality" layers on top of Mach, with others to
include Solaris, the OS/Open RTOS, sundry Win32 stuff, and even stranger
things.  (Unlike MS-Windows NT, this really _was_ a microkernel
architecture.)

To quote one of the designers (who is guilty of understatement, here):

http://www.computer.org/proceedings/hotos/7834/78340002abs.htm

   During the first half of the 1990s, IBM developed a set of operating
   system products called Workplace OS that was based on the Mach 3.0
   microkernel and Taligent's object-oriented TalOS. These products were
   intended to be scalable, portable and capable of concurrently running
   multiple operating system personalities while sharing as much code as
   possible. The operating system personalities were constructed out of a
   set of user-level personality and personality-neutral servers and
   libraries. While we made a number of important changes to Mach 3.0, we
   maintained its fundamentals and the multi-server design throughout our
   project.  In evaluating the resulting system, a number of problems are
   apparent.  There is no good way to factor multiple existing systems
   into a set of functional servers without making them excessively large
   and complex. In addition, the message-passing nature of the
   microkernel turns out to be a poor match for the characteristics of
   modern processors, causing performance problems.  Finally, the use of
   fine-grained objects complicated the design and further reduced the
   performance of the system. Based on this experience, I believe that
   more modest, more targeted operating systems consume fewer resources,
   offer better performance and can provide the desired semantics with
   fewer compromises.

About the same time, FSF was, of course, making the same error -- but 
with much less manpower and funding.  And none of the other microkernel
efforts ever got very far, either, except maybe QNX and (briefly) BeOS.

But the proof's in the pudding:  The great, breakthrough
microkernel-based OS may be Just Around the Corner<tm>.