Folklore.org: Switcher

Andy Hertzfeld, on leave from Apple, conceived a Macintosh application switcher in October 1984 after watching Byte reviewer John Markoff switch between DOS programs using Memory Shift during a Thunderscan scanner demo. The idea hinged on the recently shipped 512K Macintosh, which offered four times the memory of the original model and made running multiple applications feasible despite earlier memory conflicts. Hertzfeld, working with Thunderware's Tom Petrie and Victor Bull on the low-cost, high-resolution Thunderscan scanner, believed the switching utility was "eminently doable" and potentially "incredibly useful." The encounter matters because it planted the seed for multitasking on the Macintosh, a capability Apple's flagship platform lacked while rival DOS utilities already offered it. What to watch next: whether Hertzfeld can solve the remaining technical problems and ship the switcher as a commercial product.