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IBM 1401 Computer

1401 photo The IBM 1401 came onto the market in the early 1960's. It was called the Model T of the computer business, because it was the first mass-produced digital, all-transistorized, business computer that could be afforded by many businesses worldwide. Also, it came in just a few basic models and they were all gray.

The basic 1401 was about 5 feet high and 3 feet across. It came with 4,096 characters of memory. The memory was 6-bit (plus 1 parity bit) CORE memory, made out of little metal donuts strung on a wire mesh by workers (mostly women) at IBM factories. The 1401 in this picture has a Storage Expansion Unit (the box on the right) which expanded the core storage to an amazing 16K!! I forget what these machines cost but I'll bet they ran to six-figures.

New England Merchants Bank in the 1960's

My first introduction to the 1401 was at the bank in Boston where I worked nights in the mid-60's, paying my way through school. The 1401 I ran was connected to a huge machine called the 1419 Magnetic Check Sorter (if anyone has a picture of one, please let me know). It took handfuls of processed bank checks, read those funny coded numbers at the bottom (called MICR - Magnetic Ink Character Recognition), and copied the data onto magnetic tapes to be processed against the bank accounts of people who wrote them. It also sorted the checks into one of 20-or-so pockets so we could microfilm and store them. The 1419 went like hell and sounded like a freight train - till it got a jam and then the silence was deafening! And of course it jammed all the time, and the supervisor would look at the operator like he did it deliberately.

Well-trained computer operators

The way you controlled the 1401 was to punch a Start button, or Stop, or Reset. The way it let you know what it had to say was through little lights that would tell you if it was running, stopped, or all FU'd. And it had dials and toggle switches to enter numeric codes for other functions. The machine language command to Punch A Card was 4, so you could enter "4" with the toggle switches into core memory, and the 1401 would punch cards with a "4" in every column, all night long, if you let it.

Computer room or boiler factory?

The 1401 used a 1403 printer, which was a train, or chain, printer. The train was a belt of all the letters and numbers that spun at lightning speed, and hammers would hit the characters aginst a big ink ribbon, to make an impression on the endless rolls of fanfold paper. The reports would pile up behind the 1403 in stacks 2 feet high. It was loud too, and our computer room at the bank with 4-5 1401's, all with their check sorters, printers, and card readers going at once would have had the noise pollution police all over us, if there'd been an OSHA then.

Typical 1401 layout

1401 photo This is a typical 1401 installation. The CPU (with storage expansion unit) is on the left. Next to it is the 1403 train printer. You can see the fanfold paper feeding in from the bottom. To the right are the tape drives - they were called 7330's and the tape was vacuum loaded into columns of air. The recording density was 556 bits per inch. These are the kind of tape drives that you see whirring around with blinking lights in a lot of old movies. The fact is, the tapes often stopped because dirt got in and contaminated the read-write heads. The operators were supposed to clean the heads often, but we never did. The nice neat table in the foreground is a luxury we never had where I worked. Stuff was piled up wherever there was a square inch of space. What's missing from the picture is the uqibuitous 1402 card reader-punch - that was the main input/output device of the 1401. (Oh, yes, computer operators did wear suits to work in those days. Some of them still do.)

For a unique "1401 Experience," take the tour at Paul White's Society for Ancient Computing. Paul suggests you bring along ear plugs!

If you have some stories to share, or pictures, or have found some lapses in my memory of those early days, please write me at denichols@ridgefield-ct.com.



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