IBM 604

From: Jerome Fine <jhfine_at_idirect.com>
Date: Tue Jul 3 12:58:01 2001

>Ethan Dicks wrote:

> --- Jerome Fine <jhfine_at_idirect.com> wrote:
> > the 029 was not as particular whereas a card reader would require almost
> > perfect registration of the holes.
> Is this a difference between optical and mechanical readers, or simply
> a tolerance issue?

Jerome Fine replies:

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.

As to the actual details, I have absolutely no idea - I just punched the cards
and relied on the equipment to do the rest.

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
was required with the added character then having the correct column
available (all the rest of the columns having been shifted by one)
and thus on the second attempt it all worked correctly.

What was lots of fun was duplicating a deck of cards on an 029 keypunch.
A hand "shuffle" of blank cards between every original card and then
setting up the "drum" so that I could alternately duplicate or release
every other card while at the same time (again by hand) the output was
fed into two piles. I seem to remember it took about two hours to
duplicate a box of 2000 cards - 7200 seconds / 4000 cards - or
about two seconds per card.

Sincerely yours,

Jerome Fine
Received on Tue Jul 03 2001 - 12:58:01 BST