First, the development stage of computer information retrieval
The development of computer information retrieval is closely related to the development of computer technology and other modern science and technology. The application of computers in information retrieval began in the early 1950s. In the development history of more than 40 years, computer information retrieval has gone through three stages.
(A) offline retrieval stage
This stage is from the mid-1950s to the mid-1960s. Since 1946 February, when the world's first electronic computer came out, people have been imagining using computers to find files. Since the 1950s, data entry technologies and equipment such as punched cards and punched paper tapes have appeared in the field of computer applications, and they have been used as media for storing abstracts, searching words and inquiring questions, making computers begin to be used in the field of document retrieval.
1954, the U.S navy weapons center first established the world's first scientific and technological literature retrieval system by using IBM-70 1 computer, and realized unit phrase matching retrieval. The retrieval logic only uses "logical AND", and the retrieval result only has the contribution number. 1958 General Electric Company of the United States has improved it, and the output results have increased items such as title, author, and literature abstract. 1964, the American chemical abstracts society established an automatic document processing system, which computerized most of the work of writing abstracts, and later realized computer retrieval. In the same year, the National Library of Medicine established a computer database, that is, the medical literature analysis and retrieval system, which can not only perform logical OR, AND, NAND operations, but also retrieve documents from various channels.
At present, the retrieval service is mainly offline retrieval, which is characterized by not answering a retrieval question immediately, but focusing on a large number of questions for processing, which takes a long time and the retrieval efficiency is often not ideal. The topic-setting service in off-line retrieval is very useful for scientific and technical personnel. The problem-setting service can first register the user's questions into files according to the user's requirements and store them in the computer to form a problem file. Whenever new data enters the database, it will process this batch of data and submit the latest documents that meet the users' questions, so that users can keep abreast of the progress of the project.
(2) Online retrieval stage
This stage is from the mid-1960s to the early 1970s. Due to the development of computer time-sharing technology, the improvement of communication technology, the initial formation of computer network and the establishment of retrieval software package, users can have man-machine dialogue with the central computer of retrieval system through retrieval terminal equipment, so as to realize the purpose of remote retrieval of databases, that is, to realize online information retrieval.
During this period, the strengthening of computer processing function, the expansion of data storage capacity and the application of disk drives created conditions for the establishment of large-scale literature databases. For example, the DIALOG system, ORBIT system, BRS system in the United States and ESA-IRS system in Europe all began to be developed during this period, and all of them were actually applied in China or organizations.
It can be said that online retrieval is the product of the combination of scientific and technological information work, computer and communication technology, which marks the level of computer retrieval in the 1970s.
(3) the stage of online retrieval through the network.
This stage is from the early 1970s to the present. Because telephone network, telex network and public data communication network can transmit data for information retrieval. Especially the application of satellite communication technology makes the communication network more modern and the information retrieval system more international. Information users can directly connect with the retrieval system by means of international communication network, thus realizing international online information retrieval without geographical restrictions. In particular, the world's major retrieval systems have successively entered various communication networks. The computer of each system becomes a node on the network, and each node is connected with multiple retrieval terminals. All nodes are connected with each other through communication lines, and any terminal on the network can retrieve the data of all databases online. The realization of this online information system network enables people to search the information materials of all countries in the world in a short time, making it possible to enjoy information resources.
It can be said that online networks and retrieval terminals are almost all over the world, which makes the development of international online information retrieval reach a quite high level. There are more than 200 large-scale institutions that carry out commercial international online retrieval services, such as DIALOG Information Company in the United States, which has become the most famous online retrieval service institution in the world.
The realization of computer information retrieval greatly facilitates and accelerates the exchange and utilization of information resources, and has a far-reaching impact on social and economic development and people's scientific research methods, thus greatly promoting the progress of science and technology.