Browse Prior Art Database

Priority Control for an Integrated Communication Bus of a DP System

IP.com Disclosure Number: IPCOM000042056D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Hain, P: AUTHOR [+2]

Abstract

An integrated communication bus, hereinafter called IC bus, has the following functions in a DP system: 1. to transport input and output data from the input and output device via adapter, IC bus, buffer to the main storage of the data processing system, or vice versa, and 2. to transport control data from an I/O processor to the adapter, and back. Since at a predetermined time there can be several data transfer requests from various adapters as well as the instruction to transfer control data from the processor, a priority control has to determine the execution of the instructions in a sequence. The sequence should be arranged in such a manner that maximum advantage is achieved for the entire system and not only for predetermined I/O operations. The specific characteristics of the I/O devices, e.g.

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 52% of the total text.

Page 1 of 2

Priority Control for an Integrated Communication Bus of a DP System

An integrated communication bus, hereinafter called IC bus, has the following functions in a DP system: 1. to transport input and output data from the input and output device via adapter, IC bus, buffer to the main storage of the data processing system, or vice versa, and 2. to transport control data from an I/O processor to the adapter, and back. Since at a predetermined time there can be several data transfer requests from various adapters as well as the instruction to transfer control data from the processor, a priority control has to determine the execution of the instructions in a sequence. The sequence should be arranged in such a manner that maximum advantage is achieved for the entire system and not only for predetermined I/O operations. The specific characteristics of the I/O devices, e.g., the magnetic disk storage with mechanical motion of the data carrier and I/O devices with electronic buffering, are to be fully considered. Furthermore, the operating speed of the processor must not be reduced in that it is made to wait for its data, so that even with real time requests from I/O units to be controlled, there can be the discontinuance of I/O communication, e.g., in data tele-transfer. This will apply particularly in those cases where the transfer speed of the IC bus is restricted. It is therefore suggested to carry out priority control on two levels. The first level sorts the incoming data transfer requests and decides which request is the next to be processed. The first level does not only know the cont...