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Taliesin: A Distributed Bulletin Board System

IP.com Disclosure Number: IPCOM000128290D
Original Publication Date: 1985-Dec-31
Included in the Prior Art Database: 2005-Sep-15
Document File: 11 page(s) / 39K

Publishing Venue

Software Patent Institute

Related People

Judy L. Edighoffer: AUTHOR [+4]

Abstract

This paper describes a Computer bulletin board facility intended to support replicated bulletin boards on a network that may frequently be in a state of partition. The two major design issues covered are the choice of a name space and the choice of replication algorithms. The impact of the name space on Communication costs is explained. A special purpose replication algorithm that provides high availability and response despite network partition is introduced.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

Taliesin: A Distributed Bulletin Board System

Judy L. Edighoffer and Keith A. Lantz

Abstract

This paper describes a Computer bulletin board facility intended to support replicated bulletin boards on a network that may frequently be in a state of partition. The two major design issues covered are the choice of a name space and the choice of replication algorithms. The impact of the name space on Communication costs is explained. A special purpose replication algorithm that provides high availability and response despite network partition is introduced.

This research was supported in part by the Defense Advanced Research Projects Agency under contracts MDA903-80-C-0102 and N00039-83-K-0431, A version of this paper was presented at the Second Interational Symposium on Computer Message Systems, IFIP, September 1985.

1. Introduction

Computer systems offer a variety of facilities to assist communication between people. For example, computer based message systems deliver messages addressed to individuals while computer conferencing systems provide structured access to conversations focusing on particular topics. This paper will focus on computer bulletin board systems, in which messages are organized by topic without imposing a conversational model of user interaction.

The simplest bulletin board implementations support a single copy of each bulletin board, accessible only by users on a single node. Usually, a bulletin board is implemented as a mailbox using existing computer mail facilities [1, 2, 3]. Last read times are either kept in a separate user profile or in the mailbox, using a slightly modified mailbox format. To extend this approach to work on a network, distribution lists, each containing a list of destinations, are created. Computer mail software replicates notices by sending a copy to each destination listed. Another common technique is to use ordinary text files, usually one per topic [5]. File replication schemes can be used to distribute copies over a network.

Typically, current implementations do not support a facility.to list the names of existing bulletin boards. Furthermore, their name spaces generally lack the structure to guide such a search. Users are expected to learn about bulletin boards through word of mouth.

With the growth of distributed systems, users frequently work on multiple nodes. The usual, ad hoc replication algorithms produce inconsistent copies of bulletin boards on different nodes. This forces users to choose between missing unreplicated notices and'being inundated by multiple copies.

Ne sted distribution lists (distribution lists containing references to other distribution lists) cause problems as well. Overlapping distribution lists nested within a single parent list tend to duplicate notices. The number of copies can grow explosively with the number of overlapping

Stanford University Page 1 Dec 31, 1985

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