Browse Prior Art Database

Method to Correlate Two Half-Duplex Paths to Simulate a Full Duplex Conversation

IP.com Disclosure Number: IPCOM000103873D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 95K

Publishing Venue

IBM

Related People

Jones, D: AUTHOR [+2]

Abstract

Disclosed is a method to correlate two half-duplex communi- cation paths in a multitasking environment to simulate a full duplex conversation. The inventive feature is the way that the correlation is performed. This bulletin does not attempt to disclose the simulation of a full duplex conversation with two half-duplex paths.

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

Method to Correlate Two Half-Duplex Paths to Simulate a Full Duplex Conversation

      Disclosed is a method to correlate two half-duplex communi-
cation paths in a multitasking environment to simulate a full duplex
conversation.  The inventive feature is the way that the correlation
is performed.  This bulletin does not attempt to disclose the
simulation of a full duplex conversation with two half-duplex paths.

      This invention is intended to solve the following problem.
Note that all of these points are essential to to the environment in
which the invention is used.

1.  Establish a full duplex conversation between a connector program
    and a multitasking target program using a pair of half duplex
    communication paths.  One path will be used to send data from the
    connector to the target and the other will send data from the
    target to the connector.

2.  Each path must be driven by a separate task in the target
    program.

3.  The target does not have access to any type of unique identifier
    for a given connector.  Because of this, the connector must
    initiate communications on both half duplex paths.  As a result,
    the target has no idea when a new connection will be established.

4.  The target program must correlate the two paths that make up a
    given pair.

5.  The target must be able to support incoming connections from
    multiple connectors concurrently.

Listed below are the terms used and their definitions:

o   Communication Task:  A task in the target program that is
    dedicated to driving communications over one specific path to or
    from the connector.

o   Connector:  The program that requests a conversation with the
    target program.  The only requirement on the connector is that it
    be able to support the communication method and protocols used by
    the target program.  The tasking structure, location, and
    configuration have no bearing on this invention.

o   Path:  A software and/or hardware half-duplex communication link
    between the connector and the target.

o   Partner Tasks:  Two communications tasks that worktogether to
    simulate a full duplex conversation with a single connector by
    driving two separate half duplex paths.  One of the partners
    handlesinbound messages and the other handles outbound messages.

o   Target:  A multitasking program that communicates via the
    communication paths established by the algorithm described.

o   Task:  A dispatchable process inside of the target program.

The following algorithm is used to establish the simulated full
duplex conversation.  The attached Figure illustrates the procedure.

      Each communication path will be driven in the target program by
a dedicated communication task.  The target drives use a pair of
these communication tasks (called partner tasks) to...