In the late 1880s, the American
Herman Hollerith
invented data storage on a medium that could then be read by a machine.
Prior uses of machine readable media had been for control (
automatons such as
piano rolls or
looms), not data. "After some initial trials with paper tape, he settled on
punched cards..."
[29] Hollerith came to use punched cards after observing how
railroad conductors
encoded personal characteristics of each passenger with punches on
their tickets. To process these punched cards he invented the
tabulator, and the
key punch
machine. These three inventions were the foundation of the modern
information processing industry. His machines used mechanical
relays (and
solenoids) to increment
mechanical counters. Hollerith's method was used in the
1890 United States Census and the completed results were "... finished months ahead of schedule and far under budget".
[30]
Indeed, the census was processed years faster than the prior census had
been. Hollerith's company eventually became the core of
IBM. IBM developed punch card technology into a powerful tool for business data-processing and produced an extensive line of
unit record equipment.
By 1950, the IBM card had become ubiquitous in industry and government.
The warning printed on most cards intended for circulation as documents
(checks, for example), "Do not fold,
spindle or mutilate," became a catch phrase for the post-World War II era.
[31]
Punch card Tabulator, 1961
Leslie Comrie's articles on punched card methods and
W.J. Eckert's publication of
Punched Card Methods in Scientific Computation in 1940, described punch card techniques sufficiently advanced to solve some differential equations
[32] or perform multiplication and division using floating point representations, all on punched cards and
unit record machines.
Those same machines had been used during World War II for cryptographic
statistical processing. In the image of the tabulator (see left), note
the
control panel, which is visible on the right side of the tabulator. A row of
toggle switches is above the control panel. The
Thomas J. Watson Astronomical Computing Bureau,
Columbia University performed astronomical calculations representing the state of the art in
computing.
[33]
Computer programming in the punch card era
was centered in the "computer center". Computer users, for example
science and engineering students at universities, would submit their
programming assignments to their local computer center in the form of a
deck of punched cards, one card per program line. They then had to wait
for the program to be read in, queued for processing, compiled, and
executed. In due course, a printout of any results, marked with the
submitter's identification, would be placed in an output tray, typically
in the computer center lobby. In many cases these results would be only
a series of error messages, requiring yet another
edit-punch-compile-run cycle.
[34]
Punched cards are still used and manufactured to this day, and their
distinctive dimensions (and 80-column capacity) can still be recognized
in forms, records, and programs around the world. They are the size of
American paper currency in Hollerith's time, a choice he made because
there was already equipment available to handle bills.
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