predecessor: W Window System

project started by Robert William Scheifler and Jim Gettys
developed by MIT, DEC and IBM

versions 1 to 6
Monochrome only, ran on DEC VS100's displays connected to VAXen and VAXstations 1 and 2. 
vaxstation 100 (VS100)

version 6 ported to MicroVax
version 9 colour support added, ported to IBM/RT
X10R2 was released in January 1986, then X10R3 in February 1986

X10R3 became the first version to achieve wide deployment, with both DEC and 
  Hewlett-Packard releasing products
  source code available in file X.V10R3.tar.gz

"X is a network transparent window system for bitmap displays that
currently runs on 6 different types of displays.  These include the DEC
VS100, VS1, VS2, VS2-GPX, the Lexidata 90, and most Sun Microsystems
displays"


X1             June 1984
X10            late 1985
X10R2          Jan 1986
X10R3          Feb 1986, uwm & xgedit introduced (Ultrix Window manager)
X10R4          December 1986
X11            15 September 1987
X11R2          February 1988
X11R3          ???, xwm is dropped
X11R4          December 1989, twm introduced (ultrix wm is dropped)
X386 1.1       February 11, 1991  First version by Thomas Roell, based on X11R4.
X11R5          1991
XFree86 1.0    September 2, 1992
Accelerated-X  1994
X11R6          16 May 1994 (everything seems to coalesce at this time)
X11R6.3        1996, x2x first appears
X11R6.8        September 2004
X11R7.7        June 6, 2012