Browse Prior Art Database

Keyboard and Display with APL Character Set

IP.com Disclosure Number: IPCOM000085869D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Bouman, GH: AUTHOR [+2]

Abstract

The drawing shows part of the logic circuit for operating a keyboard and a display in either APL or EBCDIC. EBCDIC is a standard code for a character set that includes numeric and alphabetic characters that are familiar on typewriters and other keyboard devices. APL is a programming language that is particularly intended to operate from a keyboard.

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Keyboard and Display with APL Character Set

The drawing shows part of the logic circuit for operating a keyboard and a display in either APL or EBCDIC. EBCDIC is a standard code for a character set that includes numeric and alphabetic characters that are familiar on typewriters and other keyboard devices. APL is a programming language that is particularly intended to operate from a keyboard.

The unshifted APL keyboard has upper case alphabetic characters in place of the lower case alphabetic characters of an unshifted conventional typewriter. The shifted APL keyboard has special characters in place of the usual upper case alphabetic characters. APL has other special characters that are made by backspacing and overstriking special characters, or by backspacing and underlining alphabetic characters.

In some graphic displays for use with a keyboard, a dot matrix pattern for each character is stored in a read-only store, and the operation of striking a character key produces signals to access the read-only store at the location of the corresponding dot matrix pattern. A single dot matrix pattern can represent the special characters that would otherwise be produced by a backspace and a strikeover or an underline. See the IBM Technical Disclosure Bulletin, Vol. 18, No. 3, August 1975, pages 789-792.

In the system of the drawing, the selection of these character sets is controlled by the usual shift key and shift-lock key and by a key APL ON-OFF and a key APL ALTERNATE. A latch 2 and an OR gate 3 cooperate to produce a signal SHIFT whenever the shift key is held or when the shiftlock key has been keyed to set latch 2, but the shift key has not yet been keyed to re...