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From: bobr@zeus.UUCP (Robert Reed)
Newsgroups: comp.unix.wizards
Subject: Re: CYBER word length
Message-ID: <852@zeus.UUCP>
Date: Tue, 11-Nov-86 15:02:56 EST
Article-I.D.: zeus.852
Posted: Tue Nov 11 15:02:56 1986
Date-Received: Wed, 12-Nov-86 10:14:18 EST
References: <7208@elsie.UUCP> <5142@brl-smoke.ARPA> <2447@hcr.UUCP> <363@yabbie.rmit.oz> <612@astroatc.UUCP>
Reply-To: bobr@zeus.UUCP (Robert Reed)
Organization: CAE Systems Division, Tektronix Inc., Beaverton OR
Lines: 14

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.

That's a great myth.  Almost believable.  But isn't it true that the Cyber
word length was set a 60 bits to be compatible with the old CDC-6000 series?
Isn't the operant concern here to be a multiple of 6?  See, when the 6000
was born, it was a successor of the CDC-3300 series, which used 36 bit words
(like many contemporaries, such as Univac and Honeywell and DEC).  Back in
those days, most systems used 6 bit codes for characters, and DEC for
example, had machines with word sizes of 12 (PDP-8) and 18 (LINC/PDP-15)
bits.  If anything, the reason for 60 bits is historical precedent.
-- 
Robert Reed, Tektronix CAE Systems Division, bobr@zeus.TEK