Big Mac was a prototype Macintosh computer developed by Rich Page and Ralph Sahm. It had a 68020 processor, high resolution bitmapped display, and was capable of running Unisoft Unix. It was also the first Apple computer to use the Apple Desktop Bus (ADB) which, at the time, was called the Front Desk Bus (FDB). Page was one of the senior hardware engineers who left Apple when Steve Jobs formed NeXT.

Parallel Developments
Mac OS - Apple Big Mac - Apple YACC