Another trend of the 1990s in the computer industry is toward multimedia formats, as the m

arket for conventional types of computer--those that have computation and data processing as their major functions--has begun to become saturated. Multimedia computers are systems that can process graphics, sound, video, and animation in addition to traditional data processing. Videocassette recorders, televisions, telephones, and audiocassette players have recently undergone a change in technology from analog to digital formats. Television images, for example, can be processed by computer programs once they have been converted to digital signals, while those in conventional analog signals cannot. In other words, digital video images can be zoomed up or down, reshaped, or rearranged by the appropriate software. Also, due to advances in video-signal compression technology, the memory space required for storing a video program has been greatly reduced.

Multimedia has important applications for consumer products and for business needs. Video scenes that are captured by camcorders can be combined with text, sound, and data and can be viewed on television sets in homes, schools, or offices. These multimedia presentations are becoming useful educational and commercial tools. For example, there are available encyclopaedias that contain video programs depicting animal behavior, geomorphic processing, and other natural phenomena. Automobile mechanics can watch videos that demonstrate how to repair new models. In business applications, documents can be annotated with 7oice or video. New consumer products can be more effectively marketed by demonstrating how they can be used. CD-ROMs of numerous other subjects have been recently published; all of them can be viewed on TV monitors using multimedia computers. These multimedia computer systems can, in turn, be incorporated into computer networks, enhancing the effectiveness of communication.

This multitude of new products and capabilities has been made possible by the tremendous progress of microprocessor technology. Because of the advances in this area, personal computers have become more powerful, smaller, and less expensive, which has enabled computer networks to proliferate. Many of the tasks that were traditionally performed by mainframes have been transferred to personal computers connected to communications networks. Although the mainframe. continues to be produced and serves a useful purpose, it has been used more often as one of many different computers and peripheral devices connected to computer networks. In this new role, the function of mainframes as powerful processors of database systems is becoming important, and, as a result, massively parallel computers with hundreds or thousands of microprocessors are being produced. In addition to being powerful, the microprocessors used for this purpose must be inexpensive, but low costs can be achieved only if they are mass-produced. Throughout the world, more than 100, 000, 000 personal computers and 500, 000 workstations are in use, whereas only several hundred supercomputers are in operation; the numbers of mainframes and minicomputers fall somewhere between those of supercomputers and workstations. Because of such high-volume production, microprocessors for personal computers or workstations tend to be inexpensive and are available for use in massively parallel computers as well.

Multimedia computers ______.

A．can process anything but digital data

B．can even process television images

C．are rarely used in education

D．have few business applications