DESIGN AND IMPLEMENTATION OF A VIRTUAL TERMINAL PROTOCOL ON THE HP 9000 SYSTEM

Abstract

The Virtual Terminal Service is an application oriented service provided in computer networks. It is considered to lie in Application Layer, or, as a part of the Presentation layer. The Virtual Terminal Service aims to provide, with the help of a protocol called the Virtual Termi-nal Protocol, a service whereby it is possible to use any type of terminal as a peripheral device of any type of computer. This is made possible by representing the physical terminal with a data structure termed . 8s the Virtual Terminal and using the Virtual Terminal Protocol for exchanging information between the application process and the Virtual Terminal. This dissertation work considers the design and implementation of a Virtual Terminal Protocol which can be used for providing a Virtual Terminal Service on the H? 9000 system. It models-two of the most widely used types of terminal, viz, the form mode terminal and the page mode terminal. The user can select the type of terminal and its dimensions according to requirements. Switching between the two types of terminals is possible. Forms can be defined by the user of the form mode termi-nal. The terminal types and their various attributes can be changed any number of times in one session. The software for the implementation has been written in the C language.