X Window Terminals

This document details the development and evolution of X window terminals, particularly Digital's VT1000, VT1200, VT1300, and VXT 2000 models. X window terminals are presented as a cost-effective alternative to full workstations, providing users with a powerful, multi-window graphical interface to host-based applications via a network.

The core technology is the X Window System's client-server model, where an X server on the terminal handles display and input, while X clients (applications) run on host computers. This architecture enables features like multiple, resizeable windows and advanced graphics that were previously limited to workstations.

Digital's initial X terminals, the VT1000 and VT1200, used a custom operating system, ROM-based code, a TMS34010 CPU, and included local applications such as a terminal manager, window manager, and video terminal emulator to provide a consistent user interface and support both X and non-X host connections via LAT and TCP/IP. Subsequent designs, like the VT1300, evolved with different strategies, adopting downloaded code, VAX CPUs, the VAXELN operating system, and relying more on host-based customization, primarily using DECnet and TCP/IP.

The VXT 2000 X terminal represents a further advancement, addressing memory limitations through virtual memory and downloaded code, utilizing an InfoServer for load images, paging space, fonts, and customization storage, and supporting the Motif Window Manager. The paper discusses various design considerations, including hardware platform selection, operating system choices, code distribution methods (ROM vs. downloaded), communication protocols, and font management.

In conclusion, X terminals are positioned as a valuable, evolving niche product that will continue to offer networked, workstation-like functionality at a lower cost, coexisting with, rather than replacing, workstations and host systems.