Smalltalk and the Big Idea of Messaging
Smalltalk gave us object-oriented programming — but in its original sense, the big idea was messaging and late binding, not classes and inheritance. An essay on what we kept and what we lost.
Read essayThe Dynabook
Alan Kay & Smalltalk
Personal computing as a medium, objects all the way down, and the still-unfinished revolution of Smalltalk.
Alan Kay arrived at Xerox PARC in 1970 carrying a question he'd been circling for years: what would a personal computer be — not a smaller mainframe, but a genuinely new medium, owned by one person and used the way we use paper and pencil? His answer was the Dynabook, described in 1972: a notebook-sized dynamic medium "for children of all ages."
To build the software for such a machine, Kay and his team — Dan Ingalls, Adele Goldberg, and others — created Smalltalk, and with it gave object-oriented programming its original, radical meaning. Not classes and inheritance, but autonomous objects that hide their state and talk only by sending messages, bound together as late as possible, in a system that is alive and editable while it runs.
PARC under this vision produced the overlapping-window GUI, the bitmapped display, and a working sketch of personal computing a decade before it reached the public — much of which Apple and the rest of the industry then borrowed. But Kay insists the deepest part never shipped. The computer as a literacy-grade medium for thought, he says, is a revolution that hasn't happened yet. This topic is about that unfinished revolution.