In the mid-1970S, the Holy Grail of Kay's Learning Research Group at PARC was the Dynabook. A name dreamed up by Kay, Dynabook was to be a portable computer smaller than today's laptops. It would do just about everything anyone could then imagine a computer doing, including storing everything you needed on a daily basis and communicating with other computers when necessary. It was a pretty audacious idea. At the time, PARC's Alto, one of the smallest stand-alone computers then in existence, was about the size and weight of a hotel minibar refrigerator. The Dynabook was clearly way off in the future.

Kay regarded the 1973 Alto as an interim Dynabook that did the right things but was too big to carry around. In 1978 Kay and his colleague, Adele Goldberg, felt it was finally possible to build the next computer that would lead to Dynabook: Notetaker. It would be portable, use floppy disks (then a brand-new storage medium), and run on batteries. It would have only one function—it would allow students to take notes. PARC's Fairbairn set out to design the hardware and enlisted Tesler to assist.

Tesler didn't know a whole lot about hardware; his entire hardware engineering experience consisted of once building a joystick. Fairbairn, a hardware pro, said, "Hey, it's not hard," and handed him a manual for the just-introduced Intel 8086, which was to become the first commercially successful 16-bit microprocessor.

Tesler read the manual and designed the circuitry for the processor board while Fairbairn worked on the many other boards, interfaces, and specialized hardware needed. Within a week of the release of sample chips, the processor board was wrapped. And it didn't work. The fault was neither Tesler's nor his prototype software's. The Intel documentation had numbered the pins on a peripheral chip backward, and as the first developer to build a prototype, Tesler was the one who found the bug.

Because the PARC researchers' vision for the Dynabook included networking, the Notetaker was to include an Ethernet card. Existing ones contained more than 100 chips. But the size constraints for a portable machine meant the Notetaker's Ethernet card could hold 24 chips, tops. Tesler decided to move a number of functions to software, ending up needing only 20 chips. In effect, he had come up with the first software implementation of the Ethernet protocol.

The Notetaker worked; 10 prototypes were built, and Tesler and Fairbairn went on the road. They crisscrossed the country, visiting Xerox executives in several locations, trying to convince someone—anyone—that Notetaker should be a product. Some executives seemed excited but took no action beyond referring the duo to others. This went on for months.

One night in 1979, in the midst of this road show, Tesler and Fairbairn were sitting in the gate area at San Francisco International Airport, waiting to board their red-eye flight to New York City. Because the Notetaker was a secret project, they had never turned the 16-kilogram computer on outside of a Xerox building. But the gate area was nearly empty. So they opened up Notetaker, powered it up from its built-in battery, ran its Smalltalk program, and quickly turned it off again [see photo, "Road Warrior"].

"That was the first time a portable computer was ever used in an airport," Tesler says. "We think."

The duo couldn't resist, Fairbairn says, turning the computer on again, during that flight. History was made once again. The flight attendants didn't even notice.