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A Unix-Based Local Computer Network with Load Balancing Disclosure Number: IPCOM000131491D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Nov-11
Document File: 15 page(s) / 54K

Publishing Venue

Software Patent Institute

Related People

Kai Hwang: AUTHOR [+7]


Applying high-level application programs to a local computer network is a good method of balancing the workload among its host processors.

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This record contains textual material that is copyright ©; 1982 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Contact the IEEE Computer Society (714-821-8380) for copies of the complete work that was the source of this textual material and for all use beyond that as a record from the SPI Database.

A Unix-Based Local Computer Network with Load Balancing

Kai Hwang, William J. Croft, George H. Goble, Benjamin W. Wah, Faye A. Briggs, William R. Simmons, and Clarence L. Coates

Purdue University

Applying high-level application programs to a local computer network is a good method of balancing the workload among its host processors.

Many of today's computers run with Bell Laboratories' Unix operating system, including the DEC PDP-I I and VAX series, Interdata 8/32, and Honeywell 6000. ~,2 At least 5000 Unix systems are currently in operation, as compared with approximately 1000 such systems at the end of 1978. The need for linking these systems into networks has focused attention on such technical problem areas as communication protocols and Unix extensions, as well as load-balancing methods.

The problems arising from networking can be better understood in the context of the design and operational experiences associated with one particular Unix network -- the Purdue Engineering Computer Network. Of particular interest in the ECN are the load-balancing strategies embedded in its system software. Additional light can be shed on these topics by comparing the Purdue ECN with other Unix networks in terms of network configurations, protocols, and capabilities.

Two types of Unix networks have been developed in industrial and academic environments: the dial-up Unix network,3 developed at Bell Laboratories using telephone lines linking more than 80 minicomputers, and the hardwired Unix networks. Data communications through the dial-up network's leased telephone lines are slow, with a rate of 300 baud or 1200 baud. Hardwired Unix networks", however, which use dedicated links between the host computers, feature much higher data transmission rates -- rates ranging up to several M baud. The Purdue ECN4 5 is a good example of this type of network, as is the Berkeley network.6 Interested readers can also find descriptions of other networks in the literature.7~~0

The dial-up Unix network uses the UUCP (Unix-toUnix Copyist communications protocols. For the ECN, however, researchers at Purdue developed several application protocol programs to provide the capabilities of virtual terminal access, remote execution environment, f le transfer, remote device access, and user programmed l/O. These protocol programs are written in the C programming language. The Digital Equipment DMC-I I interface boards'2 are used in ECN for the physical links to execute some line control programs and relieve the ECN host processors from performing rout...