Browse Prior Art Database

Read Input From Any Keyboard

IP.com Disclosure Number: IPCOM000121767D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 95K

Publishing Venue

IBM

Related People

Mott, JM: AUTHOR [+2]

Abstract

The hardware environment for this disclosure is the IBM RISC System/6000* which is a RISC-based computer. The software running on the RISC System/6000 is IBM's AIX* Version 3.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Read Input From Any Keyboard

      The hardware environment for this disclosure is the IBM
RISC System/6000* which is a RISC-based computer.  The software
running on the RISC System/6000 is IBM's AIX* Version 3.

      The programs running at initial bring-up and installation of
the RISC System/6000 must read input from a high-function terminal
keyboard without having to rely on the possibly inaccurate keyboard
mapping information which is available in a stand-alone environment.
There are several software keyboard maps which correspond to natural
languages, but when the computer first boots from diskette or tape,
there is no reliable way to determine which keyboard mapping should
be applied in order to interpret input from an IBM high-function
terminal (HFT).  The running programs cannot ensure that the software
map being used is correct.

      Background: During installation of a RISC System/6000, it is
necessary to query the user for information needed to properly
configure the machine and proceed with the installation. Since all
IBM HFTs have numeric keys in the same keyboard position, one way to
obtain information from the user without relying on the software
keyboard map is by accepting only numeric input from the keyboard.
This is complicated, however, by the fact that some keyboard mapping
functions require a shift/numeric key sequence in order to map a key
to a number.  For instance, in order to output a 1 (one), the shift
key must be pressed at the same time as the 1 (one) key.  Therefore,
in order to read only numeric input from the keyboard, it is
necessary to mask out the shift character as well as turn off
interpretation of the key which was pressed.

      Function of readkbd: Masking shift characters and turning off
key interpretation is done by a function called readkbd which uses
key position codes in order to recognize the input of numeric keys.
Also, the enter key and the backspace key will be recognized.  All
other keys will be ignored because of inconsistencies between the
various keyboard maps. readkbd assumes that there are only two types
of keyboards: HFT and TTY.  By issuing a query to the keyboard
device, readkbd can determine if the device is a HFT or a TTY. These
two cases will be discussed separately.
Reading numeric input from a high function terminal
 1.  readkbd issues an I/O control call to determine if the keyboard
device is an hft or a tty.
 2.  If the keyboard is...