Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tekcrl!tekgvs!toma
From: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Newsgroups: comp.misc
Subject: Re: Punched Cards
Message-ID: <7626@tekgvs.LABS.TEK.COM>
Date: 7 Jun 90 15:03:57 GMT
References: <12546@netcom.UUCP> <220@taumet.COM> <12573@netcom.UUCP> <898@nlsun1.oracle.nl> <1990May29.132631.2253@pdn.paradyne.com> <1990May30.065025.25861@diku.dk> <1990Jun1.211352.4749@unhtel.uucp> <5157@stpstn.UUCP> <54@apex.UUCP>
Reply-To: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Distribution: comp
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 21


Well I had stated that the IBM 407 Accounting Machine read in the 12 edge
(like the other unit record equipment), using the digit holes to turn the
accumulator off. But the more I think about it (and unfortunately I cannot
find the reference) it probably read in the 9 edge first.

I was thinking that the 12 edge was read in first so that the zone punches
(the 12 11 and 0 ) seen first. But the 407 had two read stations, so the first
could be used to detect the zone punches. Also, mechanically, it makes more
sense for the presence of a hole to turn the accumulator digit rotation on
(and reaching the 0 punch, turn off). That way the absence of any digit
punch could be treated as a 0.

BTW as archaic as all this stuff was, I feel that all the "young whippersnappers"
that have never used any computer other than from a crt terminal have missed
a whole lot. These thing were interesting multi-processing challenges that 
build strong minds! Also, lets hear it for Analog computers! (Same reasons!)

Tom Almy
toma@tekgvs.labs.tek.com
Standard Disclaimers Apply