🚀 go-pugleaf

In article <182@dg.dg.com> rec@dg.UUCP (Robert Cousins) writes:
> However, just remember that you are throwing MIPS away doing the copying.
> I would rather have a $5 DMA controller spending the time than my high
> powered CPU.  Sure, it works to use the CPU to do the copying, but when
> you realize the amount of time the CPU may be forced to spend because of 
> the copy (including extra interrupt service, context switches, polling
> loops, cache flushes, etc.), it often turns out that a DMA controller
> can provide the user with VERY CHEAP MIPS by freeing up the CPU.  It
> is this logic which allows people to avoid using graphics processors
> in workstations by saying "the CPU is fast therefore I don't need one."

Without rejecting anything you said, let me point out that the opposite
logic can also apply though. Why install special purpose I/O intelligence
if you can ony use it for I/O. A general purpose (extra perhaps) CPU
can do all that I/O nonsense as well as other good things.  I guess it
all depends on what you want the machine to do best. Select the
criteria - then design the machine.

At this point we should adopt Mr Mashey's approach... measure then
draw conclusions on actual data.
-- 
Chris Maltby - Softway Pty Ltd	(chris@softway.sw.oz)

PHONE:	+61-2-698-2322		UUCP:		uunet!softway.sw.oz.au!chris
FAX:	+61-2-699-9174		INTERNET:	chris@softway.sw.oz.au