Beneath their personal rivalry--and occasional grudging respect--was their basic philosophical difference.
Jobs believed in an end-to-end integration of hardware and software,
which led him to build a machine that was not compatible with others.
Gates believed in, and profited from, a world in which different companies made machines that were compatible with one another;
their hardware ran a standard operating system (Microsoft's Windows)
and could all use the same software apps (such as Microsoft's Word and Excel).
"His product comes with an interesting feature called incompatibility," Gates told the Washington Post.
"It doesn't run any of the existing software. It's a super-nice computer.
I don't think if I went out to design an incompatible computer I would have done as well as he did."