Browse Prior Art Database

Maintaining Operation of an Asynchronous Communication Application Concurrent With Other Applications' Execution

IP.com Disclosure Number: IPCOM000039721D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Cook, RL: AUTHOR [+2]

Abstract

This article describes a technique for concurrently executing multiple applications programs in a personal computer (PC) when at least one application is an asynchronous (async) communications (COMM) program. (Image Omitted) The IBM PC basic input/output system (BIOS) and disk operating system (DOS) were designed under serial application execution precepts. There were no guidelines provided for writing asynchronous COMM applications in such a way as to allow multiple programs to execute concurrently. Specifically, it is a programming practice that when a program begins execution, it resets all async COMM ports. In many cases, this action is taken regardless of the actual intent of the program to actually use the port. The capability of allowing multiple applications to execute concurrently was introduced.

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Maintaining Operation of an Asynchronous Communication Application Concurrent With Other Applications' Execution

This article describes a technique for concurrently executing multiple applications programs in a personal computer (PC) when at least one application is an asynchronous (async) communications (COMM) program.

(Image Omitted)

The IBM PC basic input/output system (BIOS) and disk operating system (DOS) were designed under serial application execution precepts. There were no guidelines provided for writing asynchronous COMM applications in such a way as to allow multiple programs to execute concurrently. Specifically, it is a programming practice that when a program begins execution, it resets all async COMM ports. In many cases, this action is taken regardless of the actual intent of the program to actually use the port. The capability of allowing multiple applications to execute concurrently was introduced. However, due to the programming practice described above, if an async application was operating when another program was started, the second program's reset of the async port would cause the async application to fail.

(Image Omitted)

The technique disclosed herein utilizes a task dispatching program that notes when a program begins using an async port and assigns ownership of that port to that program. When programs other than the port owner are executing, the respective COMM port address field in the BIOS data area (location 40:00 or 40:02) is set to...