Structured Graphics for Distributed Systems

Abstract

One of the most important functions of an intelligent workstation is to provide a state-of-the-art user interface to distributed resources. One aspect of such an interface is virtual terminal support for both local and remote applications with a range of requirements, including graphics. To ensure good response for remote applications, in particular, the bulk of user interaction must be handled local to the workstation. Therefore, the terminal management software on the workstation must provide object modeling as well as viewing facilities, in contrast to most contemporary graphics systems. One way of doing this is to support structured display files. It is equally important to support simultaneous access to multiple applications; thus the terminal management software must provide window system Lscilities. Lastly, since the terminal management software should present a common interface to both local and remote applications, the workstation itself should be regarded as a multifunction component of the distributed system and not strictly as a terminal or a personal computer. This paper presents the system architecture and protocols necessary to achieve these goals and evaluates an existing implementation.

The distributed V kernel and its performance for diskless workstations

“…A simple command interpreter program allows programs to be loaded and run on the workstations using these UNIX servers. Our experience with this software to date supports the conclusions of the performance study that we can indeed build our next generation of computing facilities [8] using disldess workstations and the V kernel.…”

An experiment in integrated multimedia conferencing

“…Our own current work is based on a decade of experience building virtual terminal/window systems, graphics packages, and command interpreters [11,13,14,17]. This experience has culminated in a methodology for implementing user interfaces [12] that is based on a decomposition of user interface software into four basic components, namely:…”

“…If that interface is sufficiently highlevel (as provided, for example, by the Virtual Graphics Terminal Service [14,15]), the network load will be nowhere near as severe as that suggested by Satin and Greif [22].…”

An Empirical Study of Distributed Application Performance

“…Ultimately, all applications must communicate with the user via the virtual graphics terminal server (VGTS) resident on the user's workstation [9,16]. The VGTS provides the usual facilities present in contemporary window systems, including the ability to run any number of applications simultaneously, mapping them to the display when and where the user desires.…”