Text 2. What is a High Level Language?
A high level language is a problem oriented programming language, whereas a low level language is machine oriented. In other words, a high level language is a convenient and simple means of describing the information structures and sequences of actions required to perform a particular task.
A high level language is independent of the architecture of the computer which supports it. This has two major advantages. Firstly, the person writing the programs does not have to know anything about the computer on which the program will be run. Secondly, programs are portable, that is, the same program can (in theory) be run on different types of computer. However, this feature of machine independence is not always achieved in practice.
In most cases, programs in high level languages are shorter than equivalent programs in low level languages. However, conciseness can be carried too far, to the point where programs become impossible to understand. More important features of a high level language are its ability to reflect clearly the structure of programs written in it and its readability.
High level languages may be broadly classified as general-purpose or special-purpose. General-purpose languages are intended to be equally well suited to business, scientific, engineering or systems software tasks. The commonest general-purpose languages are Algol 68 and PL/I. The language Ada also falls into this category. Because of their broad capabilities, these languages are large and relatively difficult to use.
The commonest categories of special-purpose languages are commercial, scientific and educational. In the commercial field, Cobol still reigns supreme, while Fortran is still the most widely used scientific language. In the computer education field Basic is widely used in schools, with Logo and Prolog gaining popularity. Pascal is the most popular language at universities. Pascal is a powerful general-purpose language in its own right.
TEXT3.
Computer Manufacture
There are two overall stages in the manufacture of computers, namely original equipment manufacture, and the design and assembly of complete computer systems.
Integrated circuits are designed and developed by electronics engineers, and fabricated by highly skilled workers using sophisticated equipment. Computers are used in the design, manufacture and testing of these circuits.
The complete process of designing and constructing a computer is extremely complex, and involves the work of a number of people. The stages are generally as described in the following sections.
Most computer manufacturers have a research department, investigating new computer architectures, new hardware devices, new software techniques and new computer applications. Scientists, research engineers and technicians, as well as highly skilled software engineers are among the staff of these departments. A more detailed discussion of computing research is to be found in Section 32.5.
The overall design of a new computer, or series of computers, is in the hands of computer architects. Modern computers are designed from both the hardware and the software point of view. Accordingly, systems programmers, who write the systems software for the computer, are also involved in the design process.
Highly skilled production workers are responsible for the various stages of construction and assembly of units. Production lines are not used. Generally, a team of workers is assigned to take a unit through all stages of construction and exhaustive testing.
One of the highest paid jobs in computing is that of computer salesman. Salesmen operate in an intensely competitive environment, where their level of pay depends to some extent on their sales figures. The process of selling a large computer system can take several months.
Field engineers are responsible for the installation and commissioning of new computer units, and the maintenance and repair of systems in operation. With many computers running 24 hours a day, this type of work often involves calls at unsocial hours.