The Story So Far: Hardware

Computerworld - The Harvard Mark I was big. More than 50 feet long and weighing in at nearly five tons, it was the brainchild of Howard Aiken, a Harvard graduate student who in 1937 proposed what would become the largest electromechanical calculator ever built.

Officially known as the Automatic Sequence Controlled Calculator, the Mark I consisted of 78 adding machines and calculators linked together with mechanical counters, paper-tape-fed sequencers and card readers. And when IBM completed construction of the machine in 1944, it was the model of what computing hardware should be: a huge calculator for solving huge problems. Clearly, size mattered.

Two years later, it was dwarfed by the Electronic Numeric Integrator and Calculator, an electronic computer weighing 30 tons and requiring 1,000 square feet of floor space. In 1948, a different Mark I computer at the University of Manchester in England—the first computer to run stored programs—required a medium-size room. And in 1951, MIT's Whirlwind, the first real-time computer, took up more than 2,500 square feet.

No wonder science-fiction writer Isaac Asimov predicted in 1956 that computers would eventually grow so big that most of their bulk would have to be placed in hyperspace.

But physics and business requirements demanded that smaller, not bigger, computers be developed. By the time IBM announced its System/360 mainframe line in 1964, computers had stopped growing. In 1965, Digital Equipment Corp. squeezed a system down to a single-cabinet minicomputer, the PDP-8. And 1968's Data General Nova minicomputer could sit on a tabletop.

But except for the Cray-1 supercomputer, which was introduced in 1976 with a distinctive circular shape that allowed shorter wires and let it double as furniture, large computers would spend the next few decades shrinking into smaller rectangular cabinets.

The shape of things to come would belong to desktop computers, which arrived in 1975 with the MITS Altair 8800—a rectangular metal box that, except for the front-panel switches used to feed in programs one byte at a time, could be mistaken for a modern PC.

For the next few years, desktop computers such as the Apple II, Commodore Pet and RadioShack TRS-80 resembled video terminals. But when IBM introduced its Personal Computer in 1981, the basic shape of the majority of desktop PCs was set for the next 20 years; the biggest change was when the metal box was eventually turned on end and called a tower.

The desire to lug the computer away from the desktop led to new designs. In 1980, the Osborne I was a 25-lb. computer the size of a portable sewing machine—just small enough to fit under an airline seat. In 1982, Grid Systems Corp. began selling the first clamshell-style laptop, the 10-lb. Compass. The next year, RadioShack Corp. in Fort Worth, Texas, offered its notebook-size TRS-80 Model 100, which weighed a mere 6 lb.