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From: roy@phri.UUCP (Roy Smith)
Newsgroups: comp.arch
Subject: Re: machine word sizes
Message-ID: <2817@phri.UUCP>
Date: Sat, 25-Jul-87 10:17:10 EDT
Article-I.D.: phri.2817
Posted: Sat Jul 25 10:17:10 1987
Date-Received: Sun, 26-Jul-87 01:27:13 EDT
References: <2807@phri.UUCP> <565@saturn.ucsc.edu> <1184@k.cs.cmu.edu>
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 18

In article <1184@k.cs.cmu.edu> lindsay@k.cs.cmu.edu (Donald Lindsay) writes:
> The PDP-5, 7, 9, and 15 were 18 bit machines ( 36/2 I'm sure ). The most
> visible result of this is the silly tendency to use six-and-three characters
> for filenames ( "myfile.bas" ).

	DEC didn't let the migration to 16-bit words sway them from 6+3
filenames.  Au contrare, they simply invented the rad-50 character code so
you could pack 3 characters into 16 bits.  You got 26 upper-case letters,
10 digits, and 14 random pieces of punctuation.  Blech!  I don't remember
the exact details of rad-50 to ascii conversion, but I seem to recall it
being about as complex as 4.3's namei :-)

	If 4 bits is a nyble, and 8 bits is a byte, is the 5-1/3 bits need
to hold a rad-50 character a baubyl?
-- 
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016