Browse Prior Art Database

Port Sharing and Communication Hardware Resource Pooling

IP.com Disclosure Number: IPCOM000036472D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Gittins, RS: AUTHOR [+4]

Abstract

This invention allows for sharing of hardware resources ("port sharing") as an option (users may override this feature to provide exclusive access to a port by one application at a time). Highlights of the invention are as follows:

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Port Sharing and Communication Hardware Resource Pooling

This invention allows for sharing of hardware resources ("port sharing") as an option (users may override this feature to provide exclusive access to a port by one application at a time). Highlights of the invention are as follows:

1. More than one application may "OPEN" the same physical port. That is up to N (where N >=1) applications may think that each has exclusive access to a physical port.

2. The physical resource is committed to the application that requests communications first. Before that time, each device is transparently assigned (by the communication subsystem) an IMAGE (fully maintained by the software communication subsystem) of the port.

3. If an application is in auto-answer mode (waiting for a phone call for as long as it might be), the physical port can be "borrowed" and allocated to another application (second) with a more "urgent" need for communicating. Once the second application is finished, the port is given back to the first one, which did not even know that the port was borrowed.

During the time that a port is transparently borrowed from the first application, the data link characteristics (e.g., parity and speed setting) of the port may be changed by the borrowing (second) application. The communication subsystem, often in conjunction with the operating system, can (once the borrowing application releases the port):

1) Reprogram the physical communication port with the character...