Card readers (was: IBM 604

From: Jerome Fine <jhfine_at_idirect.com>
Date: Wed Jul 4 15:00:08 2001

>Fred Cisin (XenoSoft) wrote:

> On Tue, 3 Jul 2001, Jerome Fine wrote:
> > If a mechanical reader example is one that has a plate with 960 copper plated
> > raised areas over which the card was placed, then I would also need to know
> > how the optical mechanism functions. From what I remembered of the high
> > speed card readers, they usually fed the card into a slot around a curved
> > read area where I presume the light shone through. I would think that for the
> > light reader mechanism, timing would be critical.
> What I learned in school 35 years ago:
> Long ago, IBM patented the shape of the hole, and a few companies
> attempted to build machines with round holes! But THAT is not the
> issue. That patent was overturned.

Jerome Fine replies:

Typical of a large company to try and obtain a monopoly on an idea
that is so generic. Sounds like the DEC patent on the MSCP bit.

> Then, in their ongoing efforts to mistreat the competition, IBM patented
> their brass roller. The IBM card reading system consisted of a brass
> roller and a group of metal brushes. Which brush made contact was one
> axis, and the rotational position of the roller was the other axis. IBM's
> actions backfired. They ALMOST worked - several competitors almost went
> under when they could no longer use a brass roller. Bizarre, stupid
> things were tried, such as 960 plungers in a grid. Then one company
> (CDC?) succeeded in what had previously been too great an engineering
> challenge, and came out with an optical reader (12 photocells and a
> roller). In addition to getting around the IBM patent, they also ended up
> with a card reader that could be made to run much faster than the fastest
> that IBM had to offer; thus bringing them back from the brink and into the
> lead.

I saw the inside of one card reader which had a platform on which the
card rested while some sort of "plungers" attempted contact with 960
mountains sticking up about 1 millimetre above a bed of a non-conductive
material. Each "mountain top" was the shape of the hole and probably made
of copper which allowed for a contact through the hole (providing the chad
had been removed).

As for the CDC card reader, it definitely was MUCH faster, probably
at least 10 times the speed. The feed mechanism used air to move the
card though the slot past the photo cells. The rest of the CDC hardware
also seemed to work much better than any IBM stuff. In addition, I seem
to remember that on the UNIVAC 1107 that I used just prior to the CDC
3500 the same sort of card reader was present. What I had not realized
is that the basic design of the card reader may have come from CDC?
My experience with non-IBM hardware started around 1963 with the
UNIVAC 1107 running EXEC II is I remember correctly - a vast
improvement over what was available at the time on the IBM 7094.

> > Tolerance issue? Sorry, I have no idea as to the requirements, but I often
> > found that the first attempt to add a character with an 029 resulted in a misplaced
> > punch for just the added character - so a duplicate and a second attempt
> FIX THAT PUNCH!
> I have never had that problem with a properly aligned 029. But they DO
> need to be aligned and adjusted occasionally.
> Grumpy Ol' Fred cisin_at_xenosoft.com

I did not explain myself properly. Since I never learned to touch type, when
I wanted to add a character to a card somewhere in the middle of the
existing characters, it was possible (on an 029 with the tension correctly
adjusted) to hold the feed drum of the card being duplicated and allow
the card that was being punched to advance normally after the key stroke
had been performed. Often the tension was a little bit off and the hole
punched during that operation was misplaced. If so, a third card could
be punched that needed just one or two manual characters punched
since the rest could be punched from the second card which had all
the rest of the holes in the correct place after the one additional
column had been inserted (although slightly misplaced).

Note that sometimes the tech support would refuse to re-tension the
029 when this procedure would not work on the basis that the 029
was not designed for this operation. When that happened, I just
fell back on the fact that the tension was incorrect and after the
tech left if would always work fine for me again.

Sincerely yours,

Jerome Fine
Received on Wed Jul 04 2001 - 15:00:08 BST