VWS

When the VAXstation I shipped in 1984, VMS needed something to put on its bitmapped screen, and DEC wrote it in-house: VAX Workstation Software. Programmers saw it through UIS, User Interface Services, a library of routines for opening windows, drawing lines and text and reading the mouse and keyboard, callable from any VMS language through the common calling standard. For users it was mostly windows running VT terminal emulation, so that the text programs VMS already had could run several abreast, plus a handful of graphical demos.

VWS was DEC's alone, with no network transparency and no third-party ecosystem. At the same time DEC was funding X at MIT through Project Athena, so the outcome was never in doubt: DECwindows replaced VWS at the end of the decade, and UIS programs got a compatibility layer to keep them alive. An early instance of what became the industry rule, one home-grown window system per vendor followed by a move to X.