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The IBM 1401
Computer
Source
Karl "got his start" on
computers by going to the US Census Bureau, at night, and learning
how to program the IBM 1401. His interest continued to develop
so that he was one of the earliest to put up a web site, and now has
more than 30 web sites, more than 100,000 web pages, and more than
10,000 daily visitors to those pages.
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IBM 1401 Computer
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
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.
This
web site is a breath
of fresh air in a world of pollution.
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