50 years ago, Gates and Allen made the first Microsoft deal
The MITS Altair ticks a lot of boxes, though, and set the pattern for a lot of the future computer industry. It used an Intel 8080 microprocessor, not a bunch of discrete parts.
Donald Bitzer, Unsung Pioneer of Interactive Computing, Dies at 90
Donald Bitzer, an electrical engineer and pioneering figure in computer technology, developed the groundbreaking PLATO system at the University of Illinois in the 1960s, laying foundations for modern digital communication.
Excel's historical significance and innovation in spreadsheet software paved the way for a wide adoption of personal computing, surpassing other predecessors like VisiCalc.