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From: karl@haddock.UUCP (Karl Heuer)
Newsgroups: comp.unix.wizards
Subject: Re: CYBER word length
Message-ID: <161@haddock.UUCP>
Date: Tue, 11-Nov-86 21:47:08 EST
Article-I.D.: haddock.161
Posted: Tue Nov 11 21:47:08 1986
Date-Received: Wed, 12-Nov-86 21:27:04 EST
References: <7208@elsie.UUCP> <5142@brl-smoke.ARPA> <2447@hcr.UUCP> <363@yabbie.rmit.oz> <612@astroatc.UUCP>
Reply-To: karl@haddock.UUCP (Karl Heuer)
Organization: Interactive Systems, Boston
Lines: 19

In article <612@astroatc.UUCP> philm@astroatc.UUCP (Phil Mason) writes:
>The Cyber word length was selected to be 60 bits because of the number of 
>exact divisors it has : 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30.

I thought it was an arbitrary decision based on some piece of hardware they
had to interface to.  (Hearsay.)

>CDC thought that nobody would ever use more than 64 different symbols for
>I/O so they made their "byte" six bits long.

Actually, I believe they used "byte" to denote a 12-bit quantity, so one byte
normally contains two characters.

>Packing ten of them in a word is convenient, to say the least.

Yeah.  I liked being able to store strings in integers instead of arrays!
(This was before FORTRAN had a character type.)

Karl W. Z. Heuer (ima!haddock!karl or karl@haddock.isc.com), The Walking Lint