humming along quite nicely. The IBM 604 Electronic Calculating Punch, which IBM introduced in 1948, was a desk-sized cabinet that ate and spat out punch cards in its single-minded mission of calculating math problems — 20 to 40 addition, subtraction, multiplication or division problems for each card. Since it could process 100 cards per second, that was a lot of math … for the time.

Under the hood, more than 1,400 miniature vacuum tubes made up the guts of the machine.

And yes, it was a calculator, not a computer: All it could do was process the problems fed to it on punch cards. Its interface represented positive numbers as complements of 9, so 1 was represented by 8, 2 by 7, and so on. This was so obscure that a 12-day training session was necessary to get started with it.

But IBM’s engineers saw a way to improve things. The transistor had been invented a few years before, in 1947, by a Bell Labs research team led by William Shockley. Other companies were exploring the technology too, and a little startup called Tokyo Telecommunications Engineering would soon be introducing the first transistor radio — and renaming itself Sony in the process.

Transistors could fulfill essentially the same function in a computer as vacuum tubes did: letting one circuit control the flow of electricity in another circuit, so that switches could be turned off and on. From that basic function, clever engineers could build a whole host of logical and arithmetic processing functions.

But it took a while for the industry to realize the benefits of transistors. It wasn’t until 1954 that IBM made an experimental version of the 604 that used transistors instead of vacuum tubes.

The tech swap was probably possible only because of the modular design of the 604, which let field engineers swap out defective circuits for working ones. Presumably the same modularity let the design team replace all the vacuum tubes with transistors.

The resulting calculator was no smaller and no faster, but it did consume just 5 percent of the power of the old model, despite having 2,000 transistors inside.

Egged on by its success, IBM went on to develop the first commercial calculator that was based entirely on transistor technology: the IBM 608, released in 1958.

With more than 3,000 germanium transistors inside, the 608 was too pricey to be a commercial success. After several more IBM products had moved to the new technology, spurred in part by a mandate from company president Thomas Watson Jr., economies of scale kicked in.

Eventually, transistors became cheaper than vacuum tubes, and computing moved into a newer, faster, lower-power age.

Source: Various

Photo: IBM modified a model 604 Electronic Calculating Punch like this one to produce the world’s first transistor calculator.

See Also:

• Gallery: Low-Tech Computers From Prehistory to Today
• May 7, 1895: Calculator Learns to Multiply
• First Functional Molecular Transistor Comes Alive
• Scientists Build World's Smallest Transistor, Gordon Moore Sighs
• March 25, 1954: RCA TVs Get the Color for Money
• June 2, 1954: Airplane Takes Off, Lands Vertically
• June 27, 1954: World’s First Nuclear Power Plant Opens
• July 15, 1954: Boeing 707 Makes First Flight
• Aug. 30, 1954: Ike Inks Nuke Law
• Oct. 7, 1806: Do You Copy? Carbon Paper Patented
• Oct. 7, 1959: Luna 3's Images From the Dark Side

Authors: Dylan Tweney

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