California museums tell the history of computing

Bit by bit, they gather and display gadgets from the computer revolution.

When this computer crashes, sword blades literally jam it to a halt. Debugging requires a crowbar.

Charles Babbage's Difference Engine No. 2, one of the earliest computers, has just arrived for display May 10 at the Computer History Museum here in Mountain View. It existed only on paper for more than 150 years until, in 2002, Doron Swade and a small team assembled the five-ton computer from 8,000 bronze, iron, and steel parts.

On one side is a hand crank, on the other a spool of paper to print answers to the polynomial functions used by navigators and astronomers. Between lies the heart of the engine, rising like a gigantic abacus whose beads are interlocking gearwheels, each representing a digit. As Mr. Swade turns the machine's crank, gear teeth propel gear teeth in a whirling dervish of additions.

"By exerting physical energy, you could get results that, up until that point in time, were only achieved by mental effort," says Swade. "This was the first successful transfer of human intelligence to a machine."

The rest is computing history.

Nestled in this expanse of office parks and in the nearby mountains are two museums dedicated to preserving the history of Silicon Valley's computing culture. There's some overlap between the Computer History Museum and the considerably more informal DigiBarn Computer Museum set in the mountains outside Santa Cruz. What's different are their presentations and curatorial philosophies. Together, they make for a very nice pairing.

PCs put out to pasture

When DigiBarn curator Bruce Damer found himself in possession of a 19th-century farmstead in 1998, he was at a loss for what to do with the two-story red barn. For a self-described "nerd with a 5,000-square-foot barn," the logical answer, it seems, was to pack it with vintage computer technology. (Admission is free, but by appointment only made through its website: digibarn.com.)

Inside, the shaded windows give the light a muted, slightly dingy cast. Tables, some covered in red-checked cloths, heave with monitors, keyboards, and hard drives.

Holding up a copy of "Fumbling the Future: How Xerox Invented, Then Ignored, the First Personal Computer," Mr. Damer explains that he assembled the museum, in part, to "give Xerox its due."

Long before the Apple I, there was the Xerox Alto. By 1973, Xerox had invented most of the components that would become the personal computer and the Internet: an oversize screen complete with a desktop of icons and menus, a keyboard, and a no-nonsense three-button mouse – all connected to other Altos through an Ethernet connection.

It was widely used within the company's Palo Alto Research Center. But rather than making a commercial model available, Xerox chose to focus on copiers, ink, and toner. Not only did the Alto inspire Apple and other PCs, but, according to Damer, the Macintosh business plan was actually written on one.

Besides Apple computers of all stripes, including the Apple II and the first Macintosh – signed "Woz" by Apple cofounder Steve Wozniak – the DigiBarn displays some of the company's commercial failures, including a 1983 Lisa, which preceded the Mac.

"This is the machine that changed the world," says Damer, tapping on an IBM PC 5150 from 1981. IBM was able to produce computers quickly and relatively inexpensively by taking components made by other companies and throwing them into one box.

All this shares space with three pigs – Theo, Mama, and Piglet – who can be heard snuffling in their pen outside. Damer is a charming guide – ethnographer as much as collector. He's fascinated by the stories of the people behind the bytes and delights in sharing them. Many pieces in his collection still function, and he encourages people to turn them on.

Preserving the cutting edge

By contrast, the Computer History Museum, 30 miles north, is a much vaster and more comprehensive collection. Here, a sign reads: "Thank you for not touching the artifacts."

The museum (also free and open most afternoons) has a complex history that began outside Boston in 1979. In 2002, it moved to its new space, the former home of Silicon Graphics – itself an artifact of the computer age.

Curator Alex Bochannek dons white gloves for a tour of the restoration lab, where volunteers have reassembled an IBM 1401 system – one of those early, sprawling series of machines that occupy an entire room.

"Visible Storage," the museum's main exhibit, spreads throughout a cavernous space like a warehouse. It holds more than 600 items – only a portion of the museum's collection. A comprehensive computer timeline is being assembled to be unveiled in 2009. But for now, the Babbage Engine is the museum's star.

"Silicon Valley, and the technology industry, tends to be a community that drives with no rearview mirror," says Nathan Myhrvold, a former CTO of Microsoft who funded the Engine's construction. "As a result it's very rare to see people ... conserve or honor or display old computers."