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Browse Prior Art Database

Controlling the Use of Multiple Logical Terminals

IP.com Disclosure Number: IPCOM000036922D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 5 page(s) / 55K

Publishing Venue

IBM

Related People

Corfield, C: AUTHOR

Abstract

Terminals increasingly have the multiple Logical Terminal (LT) feature. This means a single terminal can act as if it was a number of separate terminals. Of course, a user at such a terminal enjoys the benefit of being able to run concurrent sessions, but this also brings a corresponding increase in the complexity of the environment. This disclosure discusses a general requirement where multiple screenfuls of text or image data are concurrently available to the same application; various possible conventional solutions are considered, and finally a new approach is described. This approach utilizes the power brought by multiple Logical Terminals while avoiding the complexity of multiple sessions.

This text was extracted from a PDF file.
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Controlling the Use of Multiple Logical Terminals

Terminals increasingly have the multiple Logical Terminal (LT) feature. This means a single terminal can act as if it was a number of separate terminals. Of course, a user at such a terminal enjoys the benefit of being able to run concurrent sessions, but this also brings a corresponding increase in the complexity of the environment. This disclosure discusses a general requirement where multiple screenfuls of text or image data are concurrently available to the same application; various possible conventional solutions are considered, and finally a new approach is described. This approach utilizes the power brought by multiple Logical Terminals while avoiding the complexity of multiple sessions.

Today, image data is becoming more and more commonplace. A computer installation has an application where users need to access text data (for example, stored in a STAIRS database), and view scanned images related to the text. These images are stored in the common picture library (CPL) of the Picture Retrieval & Management System PO (PRMS, 5785-EDK).

The installation's requirement is for both text and image to be conveniently accessible at once, allowing a user to jump from image to text and back again.

The terminal used is the IBM 3193 image terminal, which is designed for image and text applications. It has two Logical Terminals (LT1 and LT2), which clearly may help. The Current Problem

The current way of working of STAIRS and PRMS in a single Logical Terminal session is as follows:

For a user to view the text in a STAIRS document, the screenful of text has to be transmitted from the host to the terminal.

For a user to view an image stored in the PRMS CPL, the image has to be retrieved from the library, transmitted from the host to the terminal, and decompressed. Given the large sizes of images (around 40K compressed on average), this is bound to take some time. Each time a user references an image the above procedure is invoked if other work is performed in-between.

It is apparent that viewing an image, accessing the related text, and reaccessing the same image will be inconvenient to the user and inefficient to the system, even though the function is likely to be much required in practice. How can this problem be solved?

THE GENERAL REQUIREMENT: The above requirement is one instance of a more general requirement. This is to have concurrently available multiple screenfuls of data produced by an application, while as far as possible preserving a simple user interface. The users should not find it more complex than when they run the individual parts of the application singly (e.g., STAIRS and PRMS as described above).

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POSSIBLE CONVENTIONAL SOLUTIONS: Various methods have been devised to cater for presenting multiple screenfuls of data to a user. The scope, applicability, and strengths and weaknesses of each are discussed here.

Partitioning: Certain software (such as GDDM) suppo...