Switcher

Switcher is an early system written by Andy Hertzfeld that is the direct predecessor to Apple Computer's MultiFinder for classic Mac OS.

History
Hertzfeld was inspired to develop Switcher after observing technology writer use Memory/Shift on his IBM PC. Former colleague Bud Tribble suggested the addition of a scrolling screen to visually indicate the application switch to the user (a technique now used by Spaces).

Bill Gates expressed interested in Switcher, but Hertzfeld declined a lowball offer of $40,000 for it. Mac evangelist Guy Kawasaki arranged for Hertzfeld to demo it to Steve Jobs, who had Apple acquire it for $100,000 plus 10% of standalone sales of the product. Switcher was released in April 1985 and generated an additional $50,000 in royalties for Hertzfeld.

Hertzfeld handed off maintenance of Switcher to Phil Goldman, who eventually co-wrote MultiFinder. Hertzfeld also began work on Servant, which introduced memory allocation and simultaneous display of foreground and background applications, concepts that would appear in MultiFinder in 1987.