Vision

The technologies described, such as user interfaces and multimedia, make high demands of the processing capacity of computers. Current developments in that area still show a fast-growing processing capacity, combined with an increasing miniaturisation.

There are two important reasons for the increasing capacity of computers: the introduction of RISC (Reduced Instruction Set Computer) processors and the increasing application of parallel processing.

RISC processors
We currently see a transition from CISC processors (Complex Instruction Set Computer), which work with a relatively large set of instructions, to RISC processors, which work with a small set of simple, basic instructions. Because the RISC processor has less instructions and therefore less circuits, it is easier to make, it can be miniaturised further and it has a higher processing speed. The high processing speed more than compensates for the fact that a RISC processor must carry out more instructions than a CISC processor to execute the same command. The clock speed of the current processors is usually 100 MHz at the most. The fastest RISC processor of this moment is the Alpha processor by DEC, with 300 MHz. The speed is expected to reach 500 MHz.

For the current MS-DOS PCs, Intel still holds on to the CISC processor. All the other suppliers have equipped their computers with RISC processors, such as the PowerPC, applied by Apple and IBM in their most recent PCs.

Parallel processing
The processing capacity of a computer is further enhanced by parallel processing. This can be realised on a number of different levels.

Processor
RISC processors are more and more constructed in such a way that the processor as it were looks ahead a number of instructions and carries out unrelated instructions parallel to each other.

Multiprocessor computers
Multiprocessor computers consist of a number of processors. These computers need operating systems, DBMSs and software compilers that support parallel processing. The architectures of the applications also have to allow for parallel processing of parts of the applications. If a computer has a large number of processors, Massive Parallel Processing (MPP) is possible. MPP is very useful for applications that need a very high processing capacity, for example creating overviews out of huge quantities of data from a database, to be able to follow the progress of certain processes. MPP will also be necessary for the real-time display of interactive video games in which the computer immediately calculates the reality it presents to the user by means of video synthesis and sound synthesis.

Computer Network
A network of computers allows for the parallel distribution of the execution of application components on different computers. This can be combined with MPP, for example for the database server. The architectural principle of active objects is useful for controlling parallel processing in applications.

Human organisation
A computer network supports people working parallel in the organisation. People simultaneously use applications on their workstations and on server computers in the network. A computer network offers users unlimited storage capacity and processing capacity.

The evolution of computers
The miniaturisation and the increased capacity of processors combined with the (still) falling prices have their effect on the evolution of computers. Miniaturisation of the processors makes it possible to produce smaller computers. The mainframe is followed by minicomputers, workstations, desktop PCs and laptop PCs. Nowadays we already have Personal Digital Assistants (PDA) in the form of small pocket computers. A next phase may be that of computers the size of a credit card, or Body Computers (BC) shaped like watches or earrings.

 

Figure 4.11 The evolution of the computer.

All types of computers now exist beside each other, and their processing capacity is still growing. In workstations, PCs and PDAs this capacity growth is mainly used to improve graphical user interfaces and for multimedia applications. In mainframes and minicomputers, the capacity growth has been used mainly for realising massive on-line transaction processing.

Computers are increasingly applied in networks, in which different computers are allocated different roles. PCs and PDAs and some minicomputers are used as workstations. Via their interfaces, they support users with their work. The other minicomputers and the mainframes are used as servers. PCs and PDAs mainly support the user interfaces of the applications. The servers mainly support the operating and processing functions of applications, the storage of data and the communication between applications.

The desktop PC is a permanent workstation in the network. Within a company, desktop PCs are connected to the company network. At home, desktop PCs may be connected to company computers via the telephone. The laptop PC is meant to be a portable, individual PC. At work or at home it can be connected to the network or the telephone. If a laptop PC is fitted with a modem for data communication via mobile telephone networks, communication is also possible 'on the road'.

There is still a future for the mainframe within the network. With the further growth of the network, a great need will arise for very powerful server computers, for example for document management, knowledge navigation or communication control. These are tasks for which a mainframe could be extremely useful. The expensive processor technology currently applied in mainframes will, however, be replaced by a less expensive multiprocessor technology. This will in turn lead to an increased processing capacity and much lower prices. We will also be seeing a shift in mainframe applications. Batch processing will in the long run be replaced by parallel processing while the support of heavy server tasks in the network will grow.

Summary
Computers will be offering sufficient processing capacity even for large multimedia applications. Until the year 2000, the capacity of processors will double every two years and their price will halve. Parallel processing by multiprocessor computers and network computers will in fact provide unlimited capacity. The network makes it possible to offer the right computer - meaning a workstation or server equipped for the use it is put to - with the right capacity in the right place.