Browse Prior Art Database

Screen Manager Ring With Reordering

IP.com Disclosure Number: IPCOM000039174D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 4 page(s) / 44K

Publishing Venue

IBM

Related People

Fatahalian, FH: AUTHOR [+2]

Abstract

The Screen Manager Ring of the IBM RT 1 PC workstation identifies the currently opened Virtual Terminals and allows for management and selection of the Virtual Terminals through a user interface and through the Virtual Machine Interface screen management commands. The Screen Manager Ring is a doubly linked-list structure which provides the basic mechanism to control the virtual terminal presentation to the user. When the new terminal is opened, the Screen manager places an entry in the ring, and it removes the entry when the virtual terminal closes. The Ring has a Head position which denotes the active (visible) virtual terminal. It also has a TAIL position that represents the last virtual terminal in the Ring.

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Screen Manager Ring With Reordering

The Screen Manager Ring of the IBM RT 1 PC workstation identifies the currently opened Virtual Terminals and allows for management and selection of the Virtual Terminals through a user interface and through the Virtual Machine Interface screen management commands. The Screen Manager Ring is a doubly linked-list structure which provides the basic mechanism to control the virtual terminal presentation to the user. When the new terminal is opened, the Screen manager places an entry in the ring, and it removes the entry when the virtual terminal closes. The Ring has a Head position which denotes the active (visible) virtual terminal. It also has a TAIL position that represents the last virtual terminal in the Ring. The Screen Manager inserts a newly opened virtual terminal between the Head and the Tail and makes it the Ring Head, thus making it active.

The Screen Manager supports manipulation of the ordering of the Ring, which in effect determines the active (visible) virtual terminal.

Ring ordering is accomplished through the Virtual Machine Interface for screen management and through a User Interface to the Screen Manager. The User Interface to the Screen Manager is implemented by providing the NEXT/LAST WINDOW (NLW) key. By pressing the NLW key, the user can make the desired virtual terminal active. It is also possible to "toggle" between two virtual terminals if they are opened in the proper sequence, i.e., the second is opened while the first one is either at the Ring Head or the Ring Tail. The user, with the help of the Virtual Machine Interface, can rearrange the Ring ordering to allow the virtual terminals to be ordered in any sequence to take advantage of the "toggle" effect provided by the Screen Manager. A Virtual Machine can change the Ring ordering by issuing the Screen Manager Activate Virtual Terminal command. This amounts to removing a virtual terminal from one position in the doubly linked-list and inserting it at a different position. The Screen Manager places the identified virtual terminal between the current Head and the Tail and makes it the Ring Head, thus making it active.

The act of making a virtual terminal active is to give it the control of the input devices (keyboard, locator) and the displays. The Screen Manager Ring, with its ability to be arbitrarily reordered, provides a convenient way for the application to help the user to manage and control his or her virtual terminal, thus increasing user productivity and the machine's usability. The NLW key operation is shown in the figure and operates as follows: 1. The user presses the NLW key, and the Keyboard

Device Driver receives the hardware interrupt.

2. The Keyboard Device Driver sends a queue element,

containing the NLW key, to the Screen Manager.

3. The Screen Manager sends a keyboard command with

the active virtual terminal option to the Keyboard

Device Driver to put the keyboard in the correct

reporting mode and set...