Re: A whopping 50 percent... ???

From: JF Mezei (jfmezei.spamnot_at_teksavvy.com)
Date: 09/02/04 

Date: Thu, 02 Sep 2004 13:52:58 -0400

Michael Kraemer wrote:
> which is what presumably most people do, apart from Cobol, maybe.
> Anyway, who cares about the instruction set when everybody uses HL languages.
> (OK, compiler writers ... ;-)

RISC allowed for simpler design of chip which allowed for much higher clock
speeds. But the cost was many more instructions and bigger executables than
for CISC, so the performance was not necessarily proportional to the
impressive Mhz rates.

I'd like to know more about why early versions of Alpha had such terrible byte
manipulation. I still recall that during an early Alpha presentation at a
DECUS LUG meeting, I asked about that. So it isn't as if the Digital engineers
would have been ignorant about the need to compare bytes. (if *I* could see a
problem, then Shirley, the DEC engineers would have seen this problem too).

However, byte manipulation limits didn't apply to all RISC machines.

> when Power/PPC came around there wasn't such a large code base for it.

Actually, there was. Because Apple did such a great job with its 68k emulator,
almost all of the old 86k software, including many "extensions" (aka: drivers)
were usable from day 1 on a PPC MAC. In fact, the early versions of MAC OS on
PPC had a great deal of 68k code still in it, and they had ported only the
most used portions portions (such as graphics) where programs spent the most
time in.

It is a real shame that Digital didn't imitate Apple when it moved from VAX to
Alpha. That transition would have been far more succesful if all customers
could have just simply copied their executables, shareable images etc and
have the VMS operating system autonmatically invoke the translator dynamically
for each image file. This way, all software would have been available on Alpha
on day 1, with the natively compiled coming later for those software packages
that Palmer hadn't yet killed.

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