Today, a story about wool weaving and computers.
The University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
Weaving a pattern into cloth
is no easy matter. Different shuttles, carrying the
weft strands, have to be threaded through the warp
strands in a precise order to give the weave its
pattern. In 1805 a French engineer named
Jacquard invented means for automating that
process. He passed a chain of cards, with holes
punched in them, in front of a mechanism. The
mechanism reached through wherever a hole let it,
and picked up a thread. We've used the Jacquard
loom principle in textile mills ever since.
Five years later, in 1810, the young Englishman
Charles
Babbage went to Cambridge to study math and
mechanics. In 1816, when he was only 25, he was
made a fellow of the Royal Society for his work on
calculating-machines and methods. In 1834 he
conceived a machine that could be told how to carry
out a sequence of calculations. He conceived of
programmable computation. He never completed this
"analytical engine," as he called it, but he set
down all the essential principles of today's
digital computers.
Now, back to Jacquard's loom. The key to operating
any computer lies in transmitting sequences of
on-off commands. Babbage used Jacquard-style
punched cards. The presence or absence of a hole
communicated a simple on-off command to the
machine.
But Babbage's idea went fallow for a long time.
Meanwhile, another bright young man, Herman
Hollerith, joined the Census Office -- a world
of endless copying and tallying. Suppose someone
asked, "What percent of our population are Irish
immigrants?" How do you get an answer from millions
of data sheets?
One person had tried making ink marks on a
continuous paper roll. Then Hollerith thought of
punching holes in the paper, like a player-piano
roll. Holes registered each piece of data
mechanically, the way a player piano sounds notes.
But that lost the identity of individual records
and opened the door to nasty errors.
One day a friend said to Hollerith, "There should
be a way to use separate cards with notched edges
to keep track of data." Bingo! Hollerith saw it. He
developed a system for punching all the data for
each person into a single card. If you were a
citizen, and literate, one hole went in column 7,
row 9. He had a full system working in time for the
1890 census.
If you took up the computer before the 1980s, you
too worked with Hollerith cards -- the same size as
an 1890 dollar bill. You typed each Fortran command
on its own card.
Hollerith eventually left the Census Office to form
his own company. And today that company bears the
name International Business Machines, IBM. It's
wondrous to see how ideas turn and change and flow
-- Jacquard to Babbage to Hollerith, and
Hollerith's company, at length, building fully
evolved Babbage engines -- for us all to use.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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