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From: jgd@convex.csd.uwm.edu (John G Dobnick)
Newsgroups: comp.arch
Subject: Re: 1620 Opcode Selection
Message-ID: <7044@uwm.edu>
Date: 18 Oct 90 01:12:34 GMT
References: <34880@cup.portal.com>
Sender: news@uwm.edu
Reply-To: jgd@convex.csd.uwm.edu
Lines: 36
Originator: jgd@convex.csd.uwm.edu

From article <34880@cup.portal.com>, by R_Tim_Coslet@cup.portal.com:
> 
> The 22 (sub opcode) doesn't correspond to any character.
> 
> I have the book right infront of me.......

Unfortunately, the book is wrong.  (See... you _can't_ believe everything
you read!)

Based on actual experience (the venerable 1620 being my "first computer"
he said, waxing nostalgic), and checking the penciled in notation on
my "yellow card", a 22 would print (on a 1443 lineprinter) as a
"record mark".

  yellow card -- IBM 1620, Model 2, Reference card.  Form X26-5852-1

  record mark -- 0-2-8 punch (C82 in core).  Graphic symbol looks like
		 a 'not equal' symbol with a vertical stroke.

  1443 lineprinter -- an interesting beast, with an oscillating type
		 bar.  Characters were on (removable!) segments and
		 looked like combs - each character was at the end of 
		 a spring finger.  Switching character segments made
		 for 'interesting' output.  (The typebar could also
		 'let loose' and fly out the end of the machine. :-)


Now... does anyone out there remember the IBM 1710 ???
-- 
John G Dobnick  (JGD2)
Computing Services Division @ University of Wisconsin - Milwaukee
INTERNET: jgd@csd4.csd.uwm.edu             ATTnet: (414) 229-5727
UUCP: uunet!uwm!csd4.csd.uwm.edu!jgd

"Knowing how things work is the basis for appreciation,
and is thus a source of civilized delight."  -- William Safire