MIT/LCS/TR-368, _The X Window System_, by Scheifler and Gettys, is dated October 1986. Here are a couple paragraphs from the introduction: X is the result of the simultaneous need for a window system from two separate groups at MIT. In the summer of 1984, the Argus system [15] at the Laboratory for Computer Science needed a debugging environment for multi-process distributed applications, and a window system seemed the only viable solution. Project Athena [4] was faced with dozens, and eventually thousands of workstations with bitmap displays, and needed a window system to make the display useful. Both groups were starting with the Digital VS100 display [13] and VAX hardware, but it was clear at the outset that other architectures and displays had to be supported. In particular, IBM workstations with bitmap displays of unknown type were expected eventually within Project Athena. Portability was therefore a goal from the start. Although all of the initial implementation work was for Berkeley Unix, it was clear that the network protocol should not depend on aspects of the operating system. The name X derives from the lineage of the system. At Stanford University, Paul Asente and Brian Reid had begun work on the W window system [3], as an alternative to VGTS [12, 21] for the V system [5]. Both VGTS and W allow network-transparent access to the display, using the synchronous V communication mechanism. Both systems provide "text" windows for ASCII terminal emulation. VGTS provides graphics windows driven by fairly high-level object definitions from a structured display file; W provides graphics windows based on a simple display-list mechanism, with limited functionality. We acquired a Unix-based version of W for the VS100 (with synchronous communication over TCP [23]) done by Asente and Chris Kent at Digital's Western Research Laboratory. From just a few days of experimentation, it was clear that a network- transparent hierarchical window system was desirable, but that restricting the system to any fixed set of application-specific modes was completely inadequate. It was also clear that, although synchronous communication was perhaps acceptable in the V system (due to very fast networking primitives), it was completely inadequate in most other operating environments. X is our "reaction" to W. The X window hierarchy comes directly from W, although numerous systems have been built with hierarchy in at least some form [10, 14, 17, 27, 30, 31, 32, 33, 34, 35]. The asynchronous communication protocol used in X is a significant improvement over the synchronous protocol used in W, but is very similar to that used in Andrew [9, 19]. X differs from all of these systems in the degree to which both graphics functions and "system" functions are pushed back (across the network) as application functions, and in the ability to transparently tailor desktop management. 3. Asente. P. W Reference Manual. Stanford University, 1984. internal document. 4. Balkovich, E., Lerman, S., and Parmelee, R. "Computing in Higher Education: The Athena Experience". _Communications of the ACM 28_, 11 (Nov. 1985). 5. Cheriton, D. "The V Kernel: A Software Base for Distributed Systems". _IEEE Software 1_, 2 (April 1984). 9. Gosling, J. and Rosenthal, D. A Window-Manager for Bitmapped Displays and Unix. In _Methodology of Window-Managers_, F.R.A. Hopgood et al, Eds., Springer-Verlag, 1986. 10. Hawley, M. J., and Leffler, S. J. Windows for Unix at Lucasfilm. Summer Conference Proceedings, Portland, USENIX Association, 1985. 12. Lantz, K.A. and Nowicki, W.I. "Structured Graphics for Distributed Systems". _ACM Transactions on Graphics 3_, 1 (Jan. 1984). 13. Levy, H. "VAXstation: A General-Purpose Raster Graphics Architecture". _ACM Transactions on Graphics 3_, 1 (Jan. 1984). 14. Lipkie, D.E., Evans, S.R., Newlin, J.K., and Weissman, R.L. "Star Graphics: An Object-Oriented Implementation." _Computer Graphics 16_, 3 (July 1982). 15. Liskov, B. and Scheifler, R. "Guardians and Actions: Linquistic Support for Robust, Distributed Programs". _ACM Transactions on Programming Languages and Systems 5_, 3 (July 1983). 17. _Microsoft Windows: Programmer's Guide_. Microsoft Corporation, 1985. 19. Morris, J., et atl. "Andrew: A Distributed Personal Computing Environment". _Communications of the ACM 29_, 3 (March 1986). 21. Nowicki, W. _Partitioning of Function in a Distributed Graphics System_. Ph.D. Th., Stanford University, Stanford, CA, 1985. 23. Postel, J. Transmission Control Protocol. RFC 793, USC/Information Sciences Institute, Sept. 1981. 27. Stallman, R., Moon, D., and Weinreb, D. Lisp Machine Window System Manual. MIT Artificial Intelligence Laboratory, Aug., 1983. 30. _Programmer's Reference Manual for SunWindows_. Sun Microsystems, Inc., 1985. 31. Sweet, R. "Mesa Programming Environment". _ACM SIGPLAN Notices 20_, 7 (July 1985). 32. Sweetman, D. A Modular Window System for Unix. In _Methodology of Window-Managers_, F.R.A. Hopgood et al, Eds., Springer-Verlag, 1986. 33. _Programming the User Interface_. Symbolics, Inc., 1986. 34. Teitelman, W. The Cedar Programming Environment: A Midterm Report and Examination. CSL-83-11, Xerox PARC, June, 1984. 35. Trammel, R.D. A Capability Based Hierarchic Architecture for Unix Window Management. Summer Conference Proceedings, Portland, USENIX Association, 1985. two other references, not mentioned in the above text, that are worth noting: 11. _Information Processing: Graphical Kernel System (GKS) - Functional Description_. DIS 7942, International Standards Organization, 1982. 22. Pike, R. "The Blit: A Multiplexed Graphics Terminal". _AT&T Bell Laboratories Technical Journal 63_, 8 (Oct. 1984).