JPALME@qz.qz.se (Jacob Palme QZ) (08/21/90)
Department for computer and systems sciences Stockholm university Royal Institute of technology Research Reports on Group Communication The following research reports on Group Communication (= Computer Conferencing) services are now available. You can order the reports by writing to: Department of Computer And Systems Sciences Stockholm University Electrum 230 S-164 40 KISTA, Sweden The reports can also be ordered by phone: +46-8-16 45 00, Eva Jansson by fax phone: +46-8-703 90 25, by E-mail: evaj@vall.dsv.su.se. There is a small charge for covering our costs for paper and printing of the reports. The reports are free in orders from countries with currency restrictions. History of the COM computer conferencing system Author: Jacob Palme The COM computer conferencing system was developed and used by a group of people at the Stockholm University Computing Center in Stockholm in the years 1976-1990. This paper, written by one of the people behind the COM system, tells of how the system came to be developed and describes important occurences in the history of the system. Group Communication Functionality Author: Jacob Palme This report contains a detailed list of user functionality available in computer conferencing systems, split into about 50 functional items. The intention is that such a comprehensive survey of functions can be an aid when developing protocols for interconnecting conference systems. Use of Computer Conferencing for Systems Development Author: Jacob Palme This paper collects the experience from five medium-size to large software development projects, in which computer conferencing played an important part in the development process. The paper presents diffe- rent ways of using computer conferencing during systems develop- ment, and discusses advantages and problems with using computer con- ferencing. A final chapter proposes how computer conferencing systems could be improved so as to be more suitable as tools for systems develop- ment. News Control in Information Systems Author: Jacob Palme By news control is meant a facility to aid a user, requesting information from a data base, to get only those items of information, which the user has not got in previous queries to the same data base. News control is fundamental to computer conference systems, but many other information systems would gain by the addition of news control facilities to them. The fact, that a user often gets the same information back in different queries to a data base, may be a mayor reasons why users stop using these systems after having used them a few times. This report describes various technical solutions for achieving news control. The IPM Format as a Basis for a Message Store Author: Jacob Palme This report describes the Inter-Personal Messaging format (P2/P22 protocol) in the X.400/MOTIS messaging standard. The report discusses how properties of this format will influence the design of data bases for the storage of messages, and discusses possible extensions of the P22 protocol for use in the coordination of message stores. (By Message Store is in this report meant any data base for messages, not particularly the special case called Message Store in the X.400/MOTIS standard.) Two Techniques for a Distributed Message Data Base Author: Jacob Palme This report discusses how updating can be performed in a distributed message data base, consisting of many sub-data bases with partial overlap. In particular, two techniques for updating called pouring water and master-shadow are described and compared. A comparison of techniques for distributed data bases in message systems Author: Jacob Palme Computer Message systems can be seen as distributed data bases. This paper describes techniques used for handling the distributed data base in several message systems: The ISO/CCITT Directory System (X.500), The ISO/CCITT Message Handling System (X.400), The Usenet News System and the SuperKOM computer conference system. A Data Model for Distributed Messaging Author: Jacob Palme This report presents a data model for a distributed data base, consisting of many small and large, single-user and multi-user message stores. The report shows that updating can be done by sending atomic update operations called database revision units (DRU-s) between the stores, and that an ordinary Inter-personal message can be seen as a collection of such DRU-s. Message Store Requirements Author: Jacob Palme This report discusses requirements which can be put on a general- purpose data base for messages, especially in group communication applications. Examples of search and retrieval operations are given. Options for Distributed Group Communication Protocols Author: Jacob Palme This report discusses a number of different ways of designing distributed group communication protocols, and the pros and cons of the various alternatives. Group Communication Bibliography Author: Jacob Palme This is a bibliography, common to all the reports described above.