Original Mac calculator design came from letting Steve Jobs play with menus for 10 minutes
Rather than continuing the endless cycle of revision, Espinosa took a different approach. According to Hertzfeld, Espinosa created a program that exposed all of the calculator’s visual settings via drop-down menus: line thicknesses, button sizes, background patterns, and so on. When Jobs sat down with him, he spent about 10 minutes adjusting the settings until he found a combination he liked.
The approach worked. When given direct control over settings rather than having to verbally express his preferences, Jobs quickly arrived at a design he liked. Hertzfeld notes that he implemented the calculator’s user interface a few months later using Jobs’ parameter choices in that 10-minute session, while Donn Denman, another member of the Macintosh team, handled the math functions.
This 10-minute session spawned the design of the calculator that shipped with the Mac in 1984 and remained virtually unchanged until Mac OS 9, when Apple discontinued that operating system in 2001. Apple replaced it in Mac OS
Why it worked
Espinosa’s construction set was an early example of what would later become common in software development: visual, parameterized design tools. In 1982, when most computers displayed monochrome text, the idea of allowing someone to fine-tune visual settings via interactive controls without programming was quite cutting-edge. Later, tools like HyperCard will formalize this kind of idea into a complete visual application framework.
The calculator’s primitive design tool also revealed something about Jobs’ management process. He knew what he wanted when he saw it, but sometimes he had trouble articulating it. By giving him a direct manipulation ability, Espinosa has completely circumvented this communication problem. Later, upon his return to Apple in the late 1990s, Jobs insisted on judging products by using them directly rather than through PowerPoint demos or lists of canned specifications.
The length of Jobs’ 10-minute design session suggests the approach worked. The calculator has survived nearly two decades of Mac OS updates, outlasting many more elaborate interface elements. What started as a workaround has become one of the Mac’s simplest yet most enduring designs.
By the way, if you want to try the original Mac OS calculator yourself, you can run various older versions of the operating system in your browser thanks to the Infinite Mac website.
