Search results

Minicomputers provide an alternative means to access on‐line bibliographic retrieval systems. As the use of on‐line retrieval continues to grow and to spread into the nontechnical community, users and potential users will find it imperative to establish new methods to maximize the benefits of available on‐line systems. The paper explores the effects minicomputers can have on the on‐line retrieval environment. The experience at Editec indicates that minicomputers used in on‐line retrieval offer substantial benefits not possible using computer terminals, the major benefit being the increased acceptance of the on‐line search product by the end user community. Variable costs are held down to acceptable limits, the major consideration for those interested in their use being their high capital cost. The primary difference in using minicomputers rather than computer terminals is the ability to work at higher speeds. This enables many changes to be made which can affect the on‐line retrieval product. The decision to use minicomputers for on‐line retrieval entails lengthy analysis of current and projected use of on‐line retrieval within an organization, the availability of qualified staff, the costs of equipment and software development. It is hoped that some of the considerations in the paper may be helpful in analyzing these questions.

The results of the DIALIB project are described. This three‐year experiment of on‐line bibliographic search in the public library had as major participants four public libraries in the San Francisco Bay area. Five other public libraries in other parts of the USA participated to a lesser extent. Evaluation results were obtained concerning the users of the system and their characteristics, the use of the data bases, and librarian reactions to the system. In addition, interesting data were gathered concerning the time and cost of on‐line search, both in a free and fee‐for‐service environment.

The possibility of having access to all the world's literature from a single computer terminal stimulated the imagination of the research workers in the late' sixties. It was this goal and the fascination of the co‐operation between man and machine, that inspired the major changes that have taken place in Information Retrieval over the past ten years.

Two types of linear on‐line search have been implemented on a data base of 100,000 INSPEC records, and compared with an inverted search program on the same file. It was found that the linear search which does a character‐by‐character scan of the whole file was too slow to be useful as an on‐line search, but that the second linear search, which uses a linear file of keys to select records for full scanning, was useable on‐line. An algorithm suitable for the on‐line searching of the linear file of keys is presented with run time nearly independent of the number of terms in the search query. Neither of the linear searches can compete with an inverted search in terms of user convenience, but they do not require as complex file‐maintenance software, they use less processing time to build indexes, and they have lower storage requirements than inverted files.

The introduction of on‐line searching into a research laboratory and its acceptability vis‐a‐vis alternative information sources is discussed. In particular its cost effectiveness and its use to complement rather than to replace SDI are outlined.

For a number of reasons, I have decided to begin this issue of VINE with an editorial. In the first place, as many of you will already know, at the end of June I gave up my post as Information Officer for Library Automation in order to become an Assistant Librarian in the Applied Sciences Library of University College, Cardiff. Since the Information Officer for Library Automation is ex officio editor of VINE, this means that I will also be handing over responsibility for this publication to my successor, when he or she is appointed. Unfortunately, there will be a hiatus before my successor can take over, so that for a short while, I will continue to edit VINE. However, because of my commitments in Cardiff, I will be unable to provide news of recent developments in U.K. library automation as I formerly did. Thus, in this issue of VINE and the next, I will concentrate on descriptions of automated library systems which I visited whilst on a study tour of North America in April and May of this year. Once my successor takes over, VINE will revert to being a source of up‐to‐date information about automation in specifically U.K. libraries.

Currently available on‐line systems historically have been used as retrospective search methodologies. With interest in on‐line retrieval increasing by leaps and bounds, the application of these inverted‐file oriented systems to selective dissemination of information (SDI) services bears investigation. Within given user‐specified demands and system constraints, what is the best method of providing an SDI service? A typical batch system is compared with four types of commonly available on‐line SDI systems. The operating parameters of each are outlined, and estimates of bottom‐line costs are given.

At the beginning of the 1970s it became apparent to the Ministry of Agriculture, Fisheries and Food that the use of computers for information work merited serious consideration. We had taken part in investigations which indicated that the technology was well developed and reliable. We knew that large scale commercial services were available. What we did not know was the real value of these external services to the Ministry. All the databases concerned were derived from very familiar printed secondary journals. Did mechanized operation offer substantial advantages? Was the cost justified? How could mechanized operations fit into the present library activities? If the use of computers did offer improved facilities, what administrative arrangements were necessary? It was decided, therefore, to attempt to answer these questions by the evaluation of external computer‐based bibliographic information services under practical conditions.

With the growth in multiple on‐line search systems providing access to bibliographic data bases, exclusive availability of data bases is quickly disappearing. The searcher equally familiar with more than one system providing access to the same data base needs to apply some objective criteria in choosing a particular search system. Comparing three major search systems, we emphasize system differences in file structure, data fields and search features, and discuss how these differences influence search strategy and results. Results obtained from the CACondensates, ERIC, INFORM and NTIS data bases serve as examples for discussing the differences among the three search systems. Differences in postings among the systems are most often explained in terms of expected differences due to file structures, data fields and search features. Some unexpected differences between the systems are described and are assumed to be attributable to problems encountered during the preprocessing of the tape.

Chemical Abstracts Issues and Indexes have been available in printed form since 1907. Microform versions are also available now. In the near future Chemical Abstracts material will be accessible by computer in the UK via six on‐line systems and one batch current awareness system. This variety of modes of access is further diversified by the variety of ways in which the original Chemical Abstracts Service (CAS) files have been implemented for use with the different search systems, and by the differences in the system facilities, pricing structure and technical back‐up offered by the service suppliers. This paper attempts to bring together in tabular form factors which should be considered in taking rational decisions on how to get the ‘best’ out of Chemical Abstracts material, the ‘best’ being the optimum performance/cost ratio for any given topic.