Punch Cards

[RobS]

I know it's getting late in the day here when I get messages from people on the Pacific coast -- and I've only just had afternoon tea.

The last time that I saw anything about specifying masked ROM they were asking for paper tape. Punched cards seem risky. I remember someone accidentally emptying a boxful down the central spiral staircase of our office. That must have started an impromptu sorting job apart from the hunt on every landing. Cards could be pretty aerodynamic when you didn't want them to be.

I'm afraid my "old" reference is a 1950s book on English computing. Punched cards barely get a mention there although in the chapter on computers in America the IBM CPC is described, albeit as being slower than most of the other machines in the book. However, given the number produced they reckoned that the total processing done by CPCs probably equated to that done by the fewer number crunchers of the day. As many early computers were used for number crunching the amount of data involved was probably small in comparison to D.P. operations, so storage media wasn't a big issue.

I noticed the remark about the possibility that you were from another planet. I have never been able to trace the origin of my paternal grandfather, allegedly somewhere in South America, but my sister once told me that he had a very gruff accent, so I suspected that he was actually Klingon. Then I realised that my mother was seven of nine; it was a big family. That's not the right image to have of one's mother.

 

[Chuck(G)]

Take a look in the Motorola late 1960s databooks for, say, the XC170 read-only memory. Admittedly, at only 128 bits, the entire contents fit on a punched card, but you get the idea. Paper tape was for printer carriage control, Telex and Western Union operators and CNC machine shops. Cards were cheap and robust--and more to the point--can be easily edited.

The usual custom when working on large programs was to copy a deck of cards to tape using a source librarian program. Then, you could simply add corrections by referring to a card or range of card's identifier. (No folks, Unix didn't invent CVS). There were only two really critical paths for a large card deck--between one's filing cabinet and the card reader and the return trip. The "hit a filler strip in the raised floor and tip the cart" accident collateral damage could be ameliorated somewhat by marking the top of the deck using a felt-tip marker diagonally.

You didn't want to use a deck of cards too much, particularly if it was developing dog-eared symptoms. The 1200-card-per-minute CDC 405 reader could really make a mess if a card got caught. It had this unique capability to nicely accordion-pleat successive cards after a jam.

The 415 card punch, on the other hand, was a piece of junk--it ran hot and when it got really hot, it'd start throwing verify errors.

 

[RobS]

On the aerodynamics of cards and the habits of readers, the Honeywell 223 card reader could throw cards a long way across the room if you removed the stacker pressure plate. Operators would demonstrate their prowess by ejecting cards from the reader in this way and deftly catching them, but it wasn't a good idea to try it with the reader running at full speed, which I don't recollect but I read somewhere that it was 800cpm.