18b computers (was: something much longer and unrelated)

[dwight elvey]

----------------------------------------
> 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:
> ...
>> 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.
>

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
 
_________________________________________________________________
Hotmail® goes with you. 
http://windowslive.com/Tutorial/Hotmail/Mobile?ocid=TXT_TAGLM_WL_HM_Tutorial_Mobile1_052009