Browse Prior Art Database

Virtual Terminal Protocols

IP.com Disclosure Number: IPCOM000088347D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 5 page(s) / 115K

Publishing Venue

IBM

Related People

Stein, AJ: AUTHOR

Abstract

This system provides current and future interactive terminal support with no host modifications, device independent software, and software portability between hosts in the area of interactive terminal support.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 5

Virtual Terminal Protocols

This system provides current and future interactive terminal support with no host modifications, device independent software, and software portability between hosts in the area of interactive terminal support.

Each time a new terminal, with new protocols, is introduced to an operating system, the control program must be modified or contain device specific support to effectively join the terminal to the system. In addition, application programs have to be modified or contain device-dependent code to access and effectively utilize the terminal.

Examples of such impacts are introducing the IBM 2741 Typewriter terminal for attachment to the IBM 2260 Video Alphanumeric Display Terminal or introducing the IBM 3270 Video Alphanumeric Display Terminal for the IBM 2250 High Performance Interactive Graphics Display Terminal.

This burden can be relieved and provide a vertical and/or horizontal transition in product line in a homogeneous terminal/telecommunications environment with no modifications to the control program of the host, or software modifications to the application programs. This applies to the vertical compatibility problems of a new family of terminals with advanced design graphics systems.

With the advent of programmable communications processors (software/microcode) and the introduction of microcoded terminal architecture or firmware within the terminal product line, an intermediate terminal control interchange or ""virtual'' protocol can be established. This protocol can contain the requests and queries for specific device control and presentation. This protocol can be established within the IBM Synchronous Data Link Communications (SDLC) architecture as a terminal framing header. With this protocol approach, the application program can run on any family of terminals and divergent devices such as the IBM 3270 and IBM plasma panel, with no modifications or even re-linking.

Prior to this, the assumption that the host computer must provide compatibility with various codes, protocols and data rates of various terminals attached to it has led to an access method that is totally out of proportion to the rest of the control program.

The embodiment of this protocol can be staged at three points within the source/sink environment that is being established, as described below. 1. "Intelligent" Terminal.

The virtual terminal protocol interface can be embodied in the terminal or terminal product line. The firmware/software will provide...