Browse Prior Art Database

Channel with High Speed Data Link and Low Speed Control Link

IP.com Disclosure Number: IPCOM000038141D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Capowski, RS: AUTHOR [+2]

Abstract

In a communication technique called "outband signalling", a digital transmission link (path/bus/wire(s)/fiber(s)), used for transferring blocks of data, is complemented by a separate, additional link on which related control information is transferred. This general technique can be effectively adapted to the I/O channel of a data processing system to provide advantages over alternative designs.

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Channel with High Speed Data Link and Low Speed Control Link

In a communication technique called "outband signalling", a digital transmission link (path/bus/wire(s)/fiber(s)), used for transferring blocks of data, is complemented by a separate, additional link on which related control information is transferred. This general technique can be effectively adapted to the I/O channel of a data processing system to provide advantages over alternative designs.

In the operation of a known channel design, both data and control information is transmitted over the same path/bus/ wire(s)/fiber(s) between channel and device controller. This is called "inband signalling". In this type structure, the launch and arrival rate of control information is no different from that of the related data. This poses a problem of having to send and receive the control information (some of which may have to be interpreted and processed in real time) at an ever-faster rate as the transmission rate of the data is improved. The proposed "outband signalling" channel structure can avoid this problem.

In an I/O channel with outband signalling, data is transferred on a high speed bus by a facility called a "data mover" while related control information is transferred on a separate, lower speed link by a facility called a "channel controller". The channel controller and the data mover are interconnected to permit the channel controller to send primitive commands to the data mover and for the data mo...