Browse Prior Art Database

I/O Task Prediction

IP.com Disclosure Number: IPCOM000045006D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Dixon, JD: AUTHOR [+3]

Abstract

An input/output (I/O) task prediction mechanism is described whereby a microprocessor located in an I/O controller can determine the future workload of an I/O device coupled to the I/O controller in a manner which is transparent to and concurrent with the operation of the operating system in a host processor.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 64% of the total text.

Page 1 of 2

I/O Task Prediction

An input/output (I/O) task prediction mechanism is described whereby a microprocessor located in an I/O controller can determine the future workload of an I/O device coupled to the I/O controller in a manner which is transparent to and concurrent with the operation of the operating system in a host processor.

This is accomplished by enabling the microprocessor in the I/O controller to access control tables and queues in the host processor operating system to determine in advance the task to be required of its associated I/O device. This enables the microprocessor to begin the necessary steps to initiate the desired task before the request for same is formally dispatched from the host processor to the I/O controller. This reduces the setup time which is required when the task request is actually received, thus enabling the task to be performed more quickly and thereby providing improved system throughput.

A typical data processing system is shown in the drawing. The I/O controller includes a microprocessor (VP) and the necessary interface controls for cycle stealing data into or out of the processor main storage unit. The code located in the I/O controller for programming the microprocessor is modified to include an appropriate routine for periodically interrogating the I/O task queue in the host processor operating system. This I/O task queue is located in the processor main storage unit and is the location where future requests for I/O servic...