The transformation that produced this is one of the most studied pivots in enterprise software history. The decision was immediately unpopular among professional users who resented paying monthly for software they'd previously owned outright. Adobe's stock dropped on the announcement. Professional photographers and designers organized public complaints. None of it mattered, because the economics were unambiguous: predictable recurring revenue, higher lifetime customer value, and the ability to update software continuously rather than in expensive boxed releases every two years. John Warnock and Charles Geschke met at Xerox's Palo Alto Research Center in the late 1970s, where Warnock was working on a page description language called Interpress. Xerox wasn't interested in commercializing it. PostScript made it possible to produce print-quality output from a personal computer — something that had previously required professional typesetting equipment costing tens of thousands of dollars. Photoshop arrived in 1990, initially as a program called Display written by Thomas Knoll, a University of Michigan PhD student, and his brother John. The name "Photoshop" became so synonymous with photo editing that it entered common language as a verb — a cultural penetration that no marketing budget can manufacture. The 1993 introduction of the Portable Document Format and Acrobat established Adobe's second major platform.