In order to effectively store and disseminate knowledge, human beings have invented various material materials to record information. Ancient human knowledge is mainly recorded in Oracle Bone Inscriptions, clay tablets, animal skins, bamboo slips and so on. Since the invention of paper and printing, human knowledge has been mainly preserved and spread on paper. With the development of information recording and access technology, the forms of file carriers are becoming more and more diversified, such as audio-visual tapes, microfilms, compact discs and so on. The appearance of these non-paper documents has further expanded the scope of the documents; Speed up the production and transmission of documents; Make the storage and utilization of knowledge and information more convenient. At present, there are mainly four kinds of documents: paper, miniature, electronic and audio-visual
1. Paper file is a file formed by recording information on paper by handwriting, printing, printing, etc. It is a traditional file form, which is easy to read and circulate, but it has a small storage density and a large volume, which is not convenient for management and long-term preservation.
2. Microfilm is a document formed by using optical technology and microfilm (such as microfilm and microfilm) to record information on photosensitive materials. Its characteristics are high storage density, small size and convenient storage and transmission, but it can only be read with the help of special equipment. Many document information service organizations in the world make the documents to be collected for a long time into microfilm for preservation.
3. Electronic files refer to files in which pictures, texts, sounds, images and other information are stored in magnetic, optical and dielectric media in the form of digital codes and read by computers or similar devices, also known as machine-readable files. At present, there are many kinds of electronic documents, such as various electronic books, electronic periodicals, online databases, online databases, online news (such as newsgroups, mailing lists, BBS), CD-ROM databases, etc. Its characteristics are large information storage, short release period, easy updating, fast information transmission, fast access, integration of multimedia information such as words, images and sounds, good information appreciation and easy copying, but it can only be read by computer.
4. Audio-visual files are files formed by recording multimedia information such as sounds and images on optical materials and magnetic materials by means of audio recording, video recording, photography and video recording. They are also called audio-visual files, such as audio-visual tapes, records, slides and laser discs. Its characteristics are vivid and intuitive, especially suitable for recording complex information and natural phenomena that are difficult to describe with words and symbols, but its production and reading require special equipment.