Information Carrier

(data carrier), in data-processing machinery, an object or substance used to record and accumulate data for the purpose of feeding it directly to a computer. The information carrier is an intermediate element between the machine and the primary documents, which contain numerical data, text, charts, graphs, and so on. The reading of information from information carriers and its conversion into the electrical signals required for computer work are relatively simple.

Information carriers are distinguished in terms of physical structure (magnetic, semiconductor, or dielectric), type of material (paper, plastic, metal, or combination), form of data representation (printed, manuscript, magnetic, or punched), principle of data reading (mechanical, optical, magnetic, or electrical), and construction (tape, disk, or card). The information is recorded on the information carrier by changing the physical, chemical, or mechanical properties of the storage medium. Examples of commonly used information carriers are punched cards, punched tape, and magnetic tape. The main shortcomings of punched cards and tape are the limited information recording density (up to 10² bits per sq cm) and poor mechanical strength. Magnetic tapes have much greater information density (up to 10⁵ bits per sq cm) and can be used repeatedly (rerecording on the same tape segments).