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Article #75089Byte != 8 bits (was Re: "Open System" Redefined in OSI Specification)
From: Barry Margolin
Date: Wed, 21 Nov 1990 09:19
Date: Wed, 21 Nov 1990 09:19
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1774 bytes
In article <HARKCOM.90Nov21080149@potato.pa.Yokogawa.Co.jp> harkcom@potato.pa.Yokogawa.Co.jp (Alton Harkcom) writes:
> I never understood what the confusion was though. Are there systems
>which uses 16 bits/byte?
A byte is generally a contiguous group of bits that may be operated on as a
unit.
In high school I used a DEC PDP-8 system that had 12-bit words, and the
BASIC implementation used 6-bit characters (it didn't support lowercase
characters).
Honeywell mainframes have 36-bit words divided into four 9-bit bytes.
DEC PDP-10 and PDP-20 systems have 36 bit words, which I think are
typically divided into five 7-bit bytes (in some file formats the leftover
bit is used as a control flag).
The PDP-10/20 architecture also includes a number of byte-manipulation
instructions that take the byte size and position as parameters (I think
these are used to implement the aforementioned 5x7+1 layout).
--
Barry Margolin, Thinking Machines Corp.
barmar@think.com
{uunet,harvard}!think!barmar
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 1025b4,c0b93fb4f7d1c8eb X-Google-Attributes: gid1025b4,public X-Google-ArrivalTime: 1990-11-21 01:19:22 PST Path: arc1-ca.pugleaf.net!gmdzi!unido!mcsun!uunet!olivea!samsung!think.com!barmar From: barmar@think.com (Barry Margolin) Newsgroups: gnu.misc.discuss Subject: Byte != 8 bits (was Re: "Open System" Redefined in OSI Specification) Message-ID: <1990Nov21.091922.26992@Think.COM> Date: 21 Nov 90 09:19:22 GMT References: <GUMBY.90Nov19093839@Cygnus.COM> <MPF.90Nov19140732@triplea.cs.umd.edu> <HARKCOM.90Nov21080149@potato.pa.Yokogawa.Co.jp> Sender: news@Think.COM Distribution: gnu Organization: Thinking Machines Corporation, Cambridge MA, USA Lines: 26 Posted: Wed Nov 21 10:19:22 1990