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From: farren@hoptoad.uucp (Mike Farren)
Newsgroups: comp.unix.wizards,comp.arch
Subject: Re: *Why* do modern machines mostly have 8-bit bytes?
Message-ID: <2487@hoptoad.uucp>
Date: Wed, 22-Jul-87 05:45:04 EDT
Article-I.D.: hoptoad.2487
Posted: Wed Jul 22 05:45:04 1987
Date-Received: Fri, 24-Jul-87 02:53:36 EDT
References: <142700010@tiger.UUCP> <2792@phri.UUCP> <8315@utzoo.UUCP> <2807@phri.UUCP>
Reply-To: farren@hoptoad.UUCP (Mike Farren)
Organization: Nebula Consultants in San Francisco
Lines: 22
Xref: mnetor comp.unix.wizards:3350 comp.arch:1656

In article <2807@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:
>
>	Second (sort of the inverse of question #1), why do modern machines
>have such a strong trend towards having power-of-2 word and byte lengths?

Because most manufacturers of LSI and VLSI devices have standardized on
eight-bit wide devices (four bits for some, sixteen for others).  There are,
I'm sure, many reasons for this, including the popularity of microprocessors,
which are invariably (to my knowledge) based on an eight bit byte (exception:
those few four-bit devices); possible efficiencies in chip design when
working with a power of two (it's MUCH easier to implement 4-fold symmetry
than, say, 5-fold, and these symmetries greatly reduce the cost of designing/
manufacturing the chips); last but not least, the great benefits of standar-
dization, whatever the standard decided on.



-- 
----------------
                 "... if the church put in half the time on covetousness
Mike Farren      that it does on lust, this would be a better world ..."
hoptoad!farren       Garrison Keillor, "Lake Wobegon Days"