'Window system X' announced at MIT. Versions
1-6 were monochrome only, and ran on DEC VS100's displays connected
to VAXen and VAXstations 1 and 2.
Versions 8-10 dealt with color, for the VAXstation II/GPX. X10
is the first version that saw widespread availability and use
on many vendor's systems.
Version 11 was redesign for higher performance, more window management
styles, extensibility and better graphics capability.