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Path: utzoo!mnetor!yetti!geac!daveb
From: daveb@geac.UUCP (Dave Brown)
Newsgroups: comp.arch
Subject: Re: Size of SysV "block" (really: byte != 8 bits)
Message-ID: <933@geac.UUCP>
Date: Fri, 17-Jul-87 10:39:37 EDT
Article-I.D.: geac.933
Posted: Fri Jul 17 10:39:37 1987
Date-Received: Sat, 18-Jul-87 13:01:16 EDT
References: <218@astra.necisa.oz> <142700010@tiger.UUCP> <2792@phri.UUCP> <6705@steinmetz.steinmetz.UUCP>
Reply-To: daveb@geac.UUCP (Dave Brown)
Organization: The little blue rock next to that twinkly star
Lines: 27
Summary: Large words will return (necessarily).

In article <6705@steinmetz.steinmetz.UUCP> davidsen@kbsvax.steinmetz.UUCP (William E. Davidsen Jr) writes:
>36 bit machines usually support at least 6 and 9 bit bytes in hardware,
>...
>36 bit machines were a great idea which fell by the wayside... the extra
>bit in the byte allows many extended character sets (ASCII + 384
>others), the short is +/-262144, large enough for many applications, and
>the long is +/-64*10^9, which will hold almost any real world value.

  One of the IBM techies recently admitted in a public place that they're
using up about 1 address bit per 18 months.  Ie, applications are getting
larger rather quickly and they're having to scurry to keep up.
  Multics suffered from only (!) having 36 bits worth of word, limiting
segments (file) sizes significantly.  In fact, they promptly kludged up
a file which was really a directory of subfiles.
  Lisp and Prolog machines typically need extra bits for tagging data with
its (primitive?) type.

  Expect *ANOTHER* upheaval when you have to convert your applications
to a long word-length (or at least long address-length) machine.  One
existing machine already uses 48 bits for a "C" character pointer (I
won't mortify the manufacturer by mentioning his name).

-- 
 David (Collier-) Brown.              |  Computer Science
 Geac Computers International Inc.,   |  loses its memory
 350 Steelcase Road,Markham, Ontario, |  (if not its mind)
 CANADA, L3R 1B3 (416) 475-0525 x3279 |  every 6 months.