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Browse Prior Art Database

Low-Level Device Interface

IP.com Disclosure Number: IPCOM000101687D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 72K

Publishing Venue

IBM

Related People

Halliday, LA: AUTHOR [+2]

Abstract

The High Function Terminal Subsystem (HFT) consists of a Keyboard/ Tablet device driver, Mouse device driver, Dials/LPFK device driver, and several Display device drivers at the low level and the HFT device driver at the high level. The HFT device driver supports applications programs by providing ANSI 3.64 data stream support, multinational keyboard mapping, multiple display fonts, and multiple virtual terminals.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 70% of the total text.

Low-Level Device Interface

       The High Function Terminal Subsystem (HFT) consists of a
Keyboard/ Tablet device driver, Mouse device driver, Dials/LPFK
device driver, and several Display device drivers at the low level
and the HFT device driver at the high level.  The HFT device driver
supports applications programs by providing ANSI 3.64 data stream
support, multinational keyboard mapping, multiple display fonts, and
multiple virtual terminals.

      The HFT device driver provides a centralized control, data
routing, and data manipulation function between the lower-level
device drivers and the application program.  All data sent to or
received from the low-level devices must flow through the HFT device
driver (See Fig.  1).  The interface between the HFT and the
low-level device drivers is "private" and is not available to the
application program.

      Windowing systems, such as "X Windows", want to control and
communicate directly with the low-level device drivers. Currently,
the HFT will "get out of the way" and allow an application free
access to the display hardware.  But, there is no way to allow access
to the other low-level devices.  The HFT must be present to provide a
path to the low-level input devices (keyboard, mouse, etc.).

      Since each of the device drivers is dynamically configurable
and loadable, a mechanism for communicating between the various
device drivers and the application program should be possible.

      The H...