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The impact of electronic publishing on library services and resources in the UK

2. Electronic publishing: the present position

2.1 Typology of electronic publishing

For present purposes, an electronic publication is defined as being a publication which requires the user to employ an electronic device at some stage for its reception and/or its reading. Electronic publications may most conveniently be classified in terms of two characteristics. These are whether the content is in bit-mapped or character-coded form, and whether it is delivered to the user on a material medium or as a transmitted signal.

"Bit-mapped form" means that the electronic version of a document is essentially a description of it as a picture, so that, for example, the letter A is stored as a string of instructions (expressed as binary digits) telling the receiving apparatus where to put black and white dots in order to draw an A. A fax is an example of a bit-mapped document. "Bit-mapping", is a useful name because what one gets is a map of where the bits of the picture are placed. The result is always a facsimile, which can only be manipulated in its dimensions; it can be enlarged, reduced, rotated or topologically deformed, but its format or the relation of its parts to the whole cannot be changed. In computer terms, it can only be treated as a graphic. This means that bit-mapped texts cannot be searched algorithmically for the occurrence of particular words or phrases. They can only be searched as part of a retrieval process if they have first been indexed, and the index is stored in character-coded form. Bit-mapped document stores can be thought of as being similar to electronic microfiche, with the advantage that the images stored can be transmitted by wire, cable or broadcast. Prestel and CEEFAX pages, and the page images stored on ADONIS discs are examples of current electronic publications of this kind. Scanners (other than OCR scanners) used to transfer images to computer disk stores are devices which produce bit-mapped images.

With character-coded text, a document is made up of a series of individual codes each representing a specific letter or symbol. The near-universal code is ASCII (American Standard Code for Information Interchange), which uses eight bits to represent each letter (seven for coding data, and a parity bit). This permits a total of 128 characters, which are used to represent the lower-case and upper-case alphabets, punctuation symbols and some diacriticals. Character-coded text can be searched algorithmically, by instructing a computer to look for all occurrences of the string of signals which represents the sought term or terms. Digitised text, if it can be downloaded into a computer memory, can be manipulated very easily, as everyone who uses a word processor knows. Online databases are the classic example of digitised electronic publication. Character-coded text which is stored on a solid-state device, like the current handheld electronic dictionaries, translators and various versions of the Bible, can be searched but not manipulated, because the text cannot be copied into a computer. Character coding is applied only to text, and obviously cannot be used for graphics.

Some electronic documents, such as CD-ROMs which carry both text and images, contain both character-coded and bit-mapped information. All forms of electronic publication, except those on solid-state memory in special-purpose readers, can be copied and stored electronically, given the appropriate hardware and software. Bit-mapped text can be digitised by using an Optical Character Recognition device to scan a printout, and digitised text can be turned into a bit-mapped image using an ordinary scanner on a printout. Most materials delivered online can be downloaded and stored, either as character-coded text or graphics images, and most materials delivered electronically on one sort of physical medium can be transferred to another sort, transmitted online or printed out. One of the problems of electronic publication is its protean nature.

Another important distinction between the types of electronic publication is that of its means of transport or delivery. Some publications are delivered on a tangible medium, such as a CD-ROM, a magnetic tape, disc, or memory card, or a solid-state device incorporated in a reader, as used in hand-held electronic dictionaries. Others, like online information services, teletext and videotex are delivered via a communications medium, over wire, optical cable, satellite or broadcast. Network publishing, including electronic journals and bulletin board publication, falls into this category, as would electronic document delivery of either analogue or digitised material. Publications delivered in material form continue to be available to, if not becoming the property of, the purchaser. Those delivered by communications channels are not continually available unless recorded by being transferred to a (relatively) permanent medium; non-material publications are in effect more like services than goods.

It can be seen that the essential characteristics of electronic publication, from the point of view of the librarian and of most other users, are firstly, whether and to what extent the content of the publication can be manipulated and searched by the user; and secondly, what sort of equipment is required to receive, read and store the publication. The table below applies this typology to present forms of electronic publishing.

If your browser supports tables click here to view the table. If your browser does not support tables click here for a text version of the table.

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