X started in June 1984

• From the beginning, X's intent was mechanism, rather than policy

  • We did not believe we could (ourselves) build a good UI, but could build a system for building user interfaces
  • We never believed there should be no policy!

• Innovations:

  • X's separation of window management from base window system, a two edged sword
  • High performance streaming protocol
    • X has (until 3D hardware) been able to keep up with the hardware
    • With hindsight, could/should have gone further
    • Note: many X implementations have not been well optimized