[rescue] Perverse Question

Carl R. Friend crfriend at rcn.com
Sun Jun 15 18:53:28 CDT 2003

   Francisco Javier Mesa-Martinez writes:

>  Carl R. Friend mentions:
> >    From waht I'm given to understand, one hell of a lot of the power
> > is consumed (and, correspondingly, heat produced)  just by the clock
> > circuitry.  These boys could learn something from the async-logic
> > "of old".
> Sometimes comments like these get me, [...]

   No offence meant.

> [...] us design "boys" are perfectly aware
> of that, the whole async business being the holy savior of
> computer architecture is bogus. The tradeoff is that potentially async
> logic (whatever that is really) has a limited gain in power dissipation, while at
> the same time it increases the design complexity a big deal designing a
> fully asynch processor is a nightmare.

   Async machines were quite common in the '60s and early '70s.  And they
were quite easy to understand, too.  Take a look at PDP-6 and KA-10
schematics (formerly known as "prints") for a really good example of how
the technology worked.  It's not all that complex.

> Switching network theories are
> better understood that fully async networks. The proposers of the
> technology blissfully ignore those details, these people just think that
> clocked designs came out of the blue. There is a reason!

   It _is_ easier to understand a machine that runs internally in
lock-step with all other phases of the machine, but that doesn't
necessarily make for a "better" machine.

> BTW there is plenty of asynch logic in modern systems. Most of the logic
> inside each pipe stage is actually async... Think of a pipeline as the
> glue to put together a bunch of async pieces. I am just amazed how many
> times I have read people inveting the wheel for the ntime claiming the
> revolution is here :).

   I laughed my backside off when I read that article that "Async was
the 'wave of the future'".

> So the question is there: Do you design a superduper async system that
> takes 5 years to get out of the door, or you bet for a traditional design
> which is cheaper and is out of the door in 1 year? Granted is not as
> superduper by a factor of 10%. The problem is that by the time you release
> the superduper system, the old fart system has gone through 5 generations
> and you are only competive with the 1st generation, i.e. 4 year old
> technology... This is what everyone has had to deal with: the steam roller
> that is CMOS.

   The above model assumes that the software running on any given
machine will suffer the ongoing bloat that is so common now.  My
personal opinion (YMMV) is that 99% of that bloat is avoidable and
we can realistically (save for gaming machines -- a whole *other*
family) support 5-year cycles.  Faster clock speeds give us fatter,
less efficient software which necessitates faster clock speeds.
Loop to your heart's content or until the laws of physics are

> > >    The poor (and *ancient*...people say VAX is old?  It's newer than
> > > x86!) architecture has backed them into a very dark corner in which the
> > > only performance gains can be had by increasing the clock rate...which
> > > is nearing the end of its rope.
> They have been saying this for over 20 years. I am skeptical as usual,
> Intel has the best production technology period and they know it...

   IBM beat 'em to copper technology, and Intel have been sued at
least once (and lost) for patent infringement (Intergraph).  Intel
are not the powerhouse they're sometimes made out to be.  They're
good, yes, but they're not the masters of the universe.

> [...] thus they are taking advantage of it. Is elegant, not IMHO...
> but then again who does get to define what elegant is?

   We all do.  That's the wonder of it!

> >    Give it five years running at a core temperature that must approach
> > the boilling point of water (if not exceed it)....
> Many big iron was running under those conditions for eons, whoever the
> life cycle of most moder FeeCees is under 2 years.

   But when that was going on the manufacturers were using liquid
cooling with refrigerated water or "harder-core" technologies.  The
modern PeeCee uses a very inefficient coolant.  At least there isn't,
usually, a catastrophic release of magic smoke during the planned
lifetime (obsolesence) of the macine.

   I must say, I *do* like your spelling of Wintel kit.

| Carl Richard Friend (UNIX Sysadmin)            | West Boylston       |
| Minicomputer Collector / Enthusiast            | Massachusetts, USA  |
| mailto:crfriend at rcn.com                        +---------------------+
| http://users.rcn.com/crfriend/museum           | ICBM: 42:22N 71:47W |

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