Revised 2/21/04

The HP 9100: The Initial Journey

Sometimes it feels like the planets have aligned, the fates are all pointing at you, and “somethin’s just gonna happen.” HP’s VP of Research Barney Oliver must have felt like this in June of 1965 when he was visited by not just one but two inventors who had different but equally radical ideas for building a scientific calculator.

That both of these people should visit HP at all is noteworthy. In 1965 HP is not in the computation business. It’s an instrument company, albeit with a far-flung, international empire of manufacturing divisions and sales offices. Although HP is preparing to enter the minicomputer arena (it has just started a development program that will lead to the introduction of the HP 2116 minicomputer), HP’s involvement in any sort of computation is not yet public knowledge. HP engineers of the day are masters of the dipstick (slide rule) on which they perform daily engineering calculations. For heavier computational work, they buy a little time on a time-shared computer at Bill’s and Dave’s nearby alma mater, Stanford University.

Yet these two visitors, physicist/mathematician Malcolm Macmillan and inventor Tom Osborne, manage to find their way to HP’s R&D lab at 1501 Page Mill Road in Palo Alto within a few weeks of each other. The closely timed visits by Macmillan and Osborne spark Barney Oliver and direct some of HP’s creative engineering energy in an entirely new direction. That energy thrusts HP into the calculator business and creates a new, profitable, and very successful product line for the company.

(To see Tom Osborne’s first-hand account of this story and of the story of the HP 35 pocket calculator, click here.)

Old Line Calculation

By the 1960s, mechanical calculators (high-end adding machines) had been on the market for decades. These mechanical marvels could multiply and divide, making a tremendous racket in the process. However, these machines were not particularly well suited to engineering calculations because they lacked high-powered computational abilities, especially transcendental functions (such as sine and cosine). In fact, many of the more complex calculations performed during the Manhattan project as part of the atom bomb’s development were performed by teams of women, individually referred to as computers, who ran endless simple calculations on mechanical calculators under the direction of a “program” developed by one of the project scientists.

One of the scientists on the Manhattan project was Stanley P. Frankel, who developed intricate mathematical simulations of complex physical systems. Calculations for those simulations were performed by the female computers working for the project. Frankel later wrote computer programs for the ENIAC, the first all-electronic (neither female nor electromechanical) computer. So Frankel was very familiar with computing concepts. During the 1950s, he started to provide computer-design consulting services to companies including Librascope, General Electric, and SCM (Smith-Corona Marchant).

ENIAC, the world’s first electronic computer, was not programed but wired up to solve a problem. It became operational just in time for Stan Frankel and Nick Metropolis to run the calculations for “the Los Alamos problem,” which sought to find out if a hydrogen bomb was feasible.

Tom Osborne Photo Courtesy of Hewlett-Packard

Osborne studied Frankel’s calculator design and SCM’s production plan for a while. He then decided that the design and the production plan weren’t very good. They would either produce a machine that didn’t work at all, or one that would operate very slowly. Osborne also decided that he didn’t want to work on the Cogito 240SR project at all. In fact, he now wanted to develop a calculator design on his own and he proposed this idea to SCM’s management. SCM weighed the credentials of the freshly minted MSEE from Berkeley against the seasoned veteran from the Manhattan project and unsurprisingly decided to bet on the veteran.

Osborne then proposed a “can’t lose” deal for SCM. He would develop a calculator design on his own, taking no salary and only lab space. He would then allow SCM to buy his design if they liked it, paying him only his back wages. SCM’s management turned down Osborne’s overly generous offer, saying that it didn’t conform to company policy.

At this point, Osborne decided to leave SCM. As is often the case in issues concerning intellectual property, things turned very ugly, very quickly. SCM demanded all of Osborne’s notes and papers, which he turned over to SCM. Then SCM’s attorneys demanded that Osborne give them his calculator design, which did not yet exist. SCM had concluded that Osborne could not possibly be confident enough to propose his “can’t lose” deal for the design of a calculator unless he’d already designed one. When Osborne insisted that he hadn’t designed the calculator yet, SCM’s lawyers become even more adamant. Osborne finally hired an attorney of his own who managed to dispatch SCM’s lawyers with one well-written letter, leaving Osborne free to develop his design.

SCM did finish development of the Cogito 240SR without Osborne and put it on the market in 1966. In the words of HP’s Director of R&D Barney Oliver, the Cogito “was a miserable machine, it took forever to do anything.”

Osborne went off on his own in January, 1964 and developed a calculator that represented a radical departure from any computer or calculator design of the day. He spent most of 1964 developing the design on a card table in his apartment without the aid of engineering test equipment. Fortunately, his wife had a job and could underwrite his personal R&D efforts. Osborne created an electronic calculator that used 10-digit, floating-point numbers when all of the other electronic calculators of the day were fixed-point machines. The use of floating-point data gave Osborne’s calculator the enormous dynamic range required for scientific and engineering calculations—ranging over 200 decades—from very small numbers to very big ones. This characteristic alone made Osborne’s design ideal for a calculator intended to serve the needs of scientists and engineers.

Tom Osborne developed his calculator prototype in his apartment. Here’s he’s assembling the balsa wood case that will house the calauclator’s keyboard and display. He used tools of the modeler’s trade including balsa wood, Elmer’s Glue All, and Pactra spray ‘Namel to create a good-looking case for the prototype. Photo courtesy of Tom Osborne

Osborne painted his calculator prototype Cadillac green. Photo courtesy of Tom Osborne.

Barney Oliver Photo Courtesy of Hewlett-Packard

Tom Osborne demonstrated his calculator to several companies in his apartment, where he’d built the machine. Here, the calculator prototype (right) is readied for the showing, along with the  logic module (center box), the power supply (on top of the logic module), and a specialized tester Osborne built (to the left of the logic module) that allowed him to debug the prototype without the expensive test equipment he’d otherwise need for such a project. The white mockup calculator on the left shows how large Osborne expected a finished calculator to be, once it housed the logic and power supply in addition to the keyboard and display. Photo courtesy of Tom Osborne

Osborne shrewdly built the logic and memory for his prototype calculator into a separate box to allow the prototype keyboard and display unit to assume the size he believed would fairly represent the final production product. Otherwise, managers from prospective companies would get the impression that the calculator would be huge and unsellable. Photo courtesy of Tom Osborne.