🚀 go-pugleaf

In article <42qclc$3bu@sashimi.wwa.com>, blackbob@sashimi.wwa.com (G) writes:
|> In article <hotelca-0509952035150001@192.0.2.1>,
|> Hotel California <hotelca@cris.com> wrote:
|> 
|> >Or maybe your expectations are higher than necessary.  Sure PMT is
|> >supposed to be so much better than CMT but CMT is good.  It gets the job
|> >done.  Sure, having a supercomputer in every school with terminals on
|> >every desk would be nice but having a computer lab in every high school is
|> >good enough.
|> 
|> Your analogy is worthless.  A supercomputer costs several million
|> dollars.  Preemptive multitasking is no more expensive to  imple-
|> ment  than  cooperative.  It might be cheaper, especially from an
|> application developer's perspective.

PMT is (slightly) more expensive, because those systems that
use it must also implement and require a method of
synchronization between processes; CMT has built-in
synchronization.  The Amiga Exec, for example, which had PMT
from the beginning, had to implement signals and messages
(and in v1.2, semaphores) in order to keep its processes
from tripping over each other.  The programmer is required to
learn this complexity (though actually it's pretty simple;
Amiga Exec is very clean).  Unix also has signals
and waiting in the kernel (as well as at the user
level).

In Windows, one simply has to call a certain routine
occasionally.  That routine has the luxury of being
able to switch contexts while the system is semi-
quiescent (a luxury comparable to the single spin lock
allegedly placed on Solaris SMP kernels, which makes
them comparatively slow).

But PMT's worth it to avoid being frozen in one's tracks
by a stupid program that endlessly loops, and it does
simplify the job for the programmer who wants to write a
compute-intensive application (e.g. a raytracer, a fluid-
flow modeller, or a logic simulator, all of which do not
require user input *during* their computation runs).

But go figure -- Ami nearly dies, and Microsoft is now
the King Kong of the Komputer -- erm, computer software
industry. :-)  The future Amiga may need to have the
capability to run Win32 software. :-(

Oh that's right, we'll all use Windows NT.  How silly
of me. :-)  Amiga's 256K (now 1M or so) versus WinNT's 20M.
No contest. :-P

|> 
|> 92%  of  the industry has PMT, so it's hardly something which I'd
|> call luxurious.  Heck, not everybody has a CD-ROM reader, but  it
|> is by no means a luxury.

How does one measure the % of the industry that has PMT?
Heck, what *is* the "industry"?  Are you referring to all
Unix seats divided by all seats everywhere?  Or what?
[Not a flame, but an honest question.]

(And even Win16 has PMT -- for DOS windows only, but
hey, it's PMT. :-) How does one count that?? :-) )

|> 
|> Cheers, Terry Murphy

-- 
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eric_williams@mentorg.com
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