23 May
2009
23 May
'09
10:57 a.m.
----------------------------------------
Date: Fri, 22 May 2009 01:51:34 -0500
From: frustum at pacbell.net
To:
Subject: 18b computers (was: something much longer and unrelated)
[changed the subject line due to drift]
bfranchuk at jetnet.ab.ca wrote:
...
9th bit was often used for parity. I had a PC once with
parity that used 3 bit chips on the SIMMs.
Nicolet used a 20 bit computer as a balance between
dynamic range, for signal processing, and cost of core
memory ( although I wish it was 24 bits ).
Dwight
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Grumbles at the lack of 9 bit wide ram chips
If solving that problem is a hurdle, you have much bigger problems that
you don't know about yet. :-)
... No matter how you look at it
any kind of 18 bit computer has power compared to a 16 bit or less cpu.
I think you are in love with the idea more than an actual computer.
It is trivial to imagine an anemic 18b computer that doesn't compare
well to a decent 16 bitter.
I worked on/helped design a CPU that used 9b bytes, with a 72b word
size. We sold a few million chips, which in the market we were in was a
miserable failure (this was in the mid 90s). The company was Chromatic
Research, and the first chip was called MPACT 1. That was followed up a
couple years later with MPACT 2.
The 9 bittedness came about because our memory system was based on
Rambus memory. We were one of the early adopters, due to the fact that
Chromatic Research and Rambus had a common founder, Mike Farmwald. At
the time, all Rambus parts were x9, so the 9th bit was supposedly "free"
and we might was well take advantage of it.