VII. Programs and programming languages

Conclusion

Applications of fifth generation computers

A very wide range of applications are planned for fifth generation computers, although their precise capabilities will not become clear until more development work has been done. Many applications will be expert systems of some sort.

The main industrial application is likely to be intelligent robots, with some degree of visual perception, and the ability to be instructed to attain certain goals, rather than to perform a sequence of steps, as at present. The robot will work out the sequence of steps to be performed, according to the goals, and external conditions of which it is aware.

Military applications include strategic and tactical planning and decision support systems, and automated weapons systems. The latter include intelligent guidance systems for missiles, and missile defence systems for aircraft and ships. Digital communications systems which are secure against electronic counter-measures are a likely by-product of VLSI chip design.

In commerce, corporate knowledge bases are likely to be constructed on top of corporate databases. Decision support systems for managers will use these knowledge bases to assist with planning and evaluation. The voice-activated word processor is the ultimate aim of a number of fifth generation projects, with a very large potential market awaiting the first team to achieve it. Automatic, or (more realistically) semi-automatic language translation systems are a similar application.

The fifth generation development projects are the main thrust of computer development for the next five to ten years. Large sums of money, and the time and energy of some of the leading IT experts in the world are being devoted to the work. The risks are very high, since many of the principles on which fifth generation computers are to be built did not exist five years before the start of the projects. However, the risks of withdrawing from the work are even higher. It is quite clear that if any national or regional group achieves a significant lead in the development of fifth generation computers, that group will be the dominant force in information technology.

Computers can deal with different kinds of problems if they are given the right instructions for what to do. Instructions are first written in one of the high-level languages, e.g. FORTRAN, COBOL, ALGOL, PL/I, PASCAL, BASIC, or C, depending on the type of problem to be solved. A program written in one of these languages is often called a source program, and it cannot be directly processed by the computer until it has been compiled, which means interpreted into machine code. Usually a single instruction written in a high-level language, when transformed into machine code, results in several instructions. Here is a brief description of some of the many high-level languages:

FORTRAN acronym for FORmula TRANslation. This language is used for solving scientific and mathematical problems. It consists of algebraic formulae and English phrases. It was first introduced in the United States in 1954.

COBOL acronym for COmmon Business-Oriented Language. This language is used for commercial purposes. COBOL, which is written using English statements, deals with problems that do not involvea lot ofmathematical calculations. It was first introduced in 1959.

ALGOL acronym for ALGOrithmic Language. Originally called IAL,

which means International Algebraic Language. It is used for

mathematical and scientific purposes. ALGOL was first introduced in Europe in 1960.

PL/I Programming Language I. Developed in 1964 to combine

features of COBOL and ALGOL. Consequently, it is used for data processing as well as scientific applications.

BASIC acronym for Beginner's All-purpose Symbolic Instruction

A. Code. Developed in 1965 at Dartmouth College in the United States for use by students who require a simple language to begin programming.

С developed in the 1970s to support the UNIX operating system. С is a highly portable general-purpose language.

Other such languages are APL (developed in 1962), PASCAL (named after Blaise Pascal and developed in 1971), and LISP and PROLOG, both of which are used for work in artificial intelligence. LOGO is a development of LISP which has been used to develop computer-based training (CBT) packages.

When a program written in one of these high-level languages is designed to do a specific type of work such as calculate a company's payroll or calculate the stress factor on a roof, it is called an applications program. Institutions either purchase these programs as packages or commission their own programmers to write them to meet the specifications of the users.

The program produced after the source program has been converted into machine code is referred to as an object program or object module. This is done by a computer program called the compiler, which is unique for each computer. Consequently, a computer needs its own compiler for the

various high-level languages if it is expected to accept programs written in those languages. For example, in order that an IBM RS/6000 may process a program in FORTRAN, it needs to have a compiler that would understand that particular model and the FORTRAN language as well.

The compiler is a systems program which may be written in any language, but the computer's operating system is a true systems program which controls the central processing unit (CPU), the input, the output, and the secondary memory devices. Another systems program is the linkage editor, which fetches required systems routines and links them to the object module (the source program in machine code). The resulting program is then called the load module, which is the program directly executable by the computer. Although systems programs are part of the software, they are usually provided by the manufacturer of the machine.

Unlike systems programs, software packages are sold by various vendors and not necessarily by the computer manufacturer. They are a set of programs designed to perform certain applications which conform to the particular specifications of the user. Payroll is an example of such a package which allows the user to input data - hours worked, pay rates, special deductions, names of employees - and get salary calculations as output. These packages are coded in machine language (Os and Is) on magnetic tapes or disks which can be purchased, leased, or rented by users who choose the package that most closely corresponds tо their needs.

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