🚀 go-pugleaf

albaugh@agames.com (Mike Albaugh) wrote:
> Gertjan Klein (gklein@xs4all.nl) wrote:

> 	Reality check time. The _best_ a 64-bit data bus can do is
> twice the throughput of an otherwise identical 32-bit data bus.
> This is one of those "Speed of light" issues (guaranteed not to
> exceed). Unless you do only memcpy() of your entire data space,
> you will not actually reach this figure.

  You won't get an arguement from me; I completely agree. The point I
was trying to make was that increasing the _address_ bus doesn't get
you any improvement in throughput at all, as Michael Smith originally
claimed. 

> :   I guess that what all this proves is that the phrase "64-bit
> : machine" is nonsensical. 64-Bit by what definition? External or
> : internal bus, data or address, register size? Without this
> : information, "64-bit machine" tells you _nothing_.

> 	It tells you the marketroids are in firm control :-)
> I started out in this business on a machine with (potentially)
> a 96Kbit "word length", but at 11uSec per 7 bits, it was not
> exactly a speed demon :-)

  I've been programming a few older microcontrollers a few times, and
a 64-bit _anything_ wouldn't have made me happy ;-) I also wonder if
someone using a computer to mainly manipulate 8-bit-byte-sized
characters is impatiently awaiting his new "64-bit machine". (Now that
I come to think of it, I'm afraid he is... ;-)

  Gertjan.

-- 
Gertjan Klein   <gklein@xs4all.nl>