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Salient: Victoria University Students' Paper. Vol. 29, No. 6. 1966.

Data Processing

page 11

Data Processing

Without Question the electronic computer has become a most important influence in our everyday lives. Some writers claim that this is the computer age. that the phenomenal growth and acceptance of electronic data processing ranks in significance with atomic power development or the achievements in space exploration. Indeed, it is true that in nearly every fleld of human endeavour, there is an increasing degree of dependence being placed upon the operation of our most fascinating machine—the electronic computer.

By the end of 1967 there will be more then one hundred machines installed In New Zealand; throughout the world more than thirty thousand machine systems will be in operation.

At least seven of New Zealand's computers will be installed in universities for educational administrative and research purposes. The demand from students for computer facilities has been staggering, so much so that the machines at present installed are easily the busiest in the country, operating round the clock seven days a week.

The Government has invested heavily in data processing equipment over the last five years, already employing eight major installations for administrative, accounting and seientific applications.

Until recently, it was only the large commercial enterprise, often with overseas affiliation or control, that was taking advantage of the computer in everyday business administration. But nowadays two factors have encouraged many New Zealand owned enterprises to place orders for modern electronic machines. Firstly, research, worldwide demand, and keen competition amongst the manufacturers have brought the price of a computer down to a level where many companies must give serious consideration to installation Mation on economic factors alone.

Secondly, as a country, we have acquired sufficient expertise for most informed businessmen to be assured of the machine's capability and reliabilty.

It is safe to predict that within a few years an understanding of computer capabilities will be an essential qualification of every business and professional man. every scientist and engineer.

It is with this development in mind that this brief discussion of electronic data processing in New Zealand is presented.

It is appropriate now to discuss some of the physical characteristics of the computer.

In general there are four main components:

1. Input.

2. Processing.

3. Storage.

4. Ouput.

These components may be grouped in many configurations but all machine systems have the same fundamental organisation.

diagram showing model of computer functions

As one example, a set of meter readings taken at 10-minute intervals over the last 24 hours may be "input" to the computer. These are "processed" to calculate mean hourly levels which may be "output" in tabular form. Simultaneously, these hourly lewls are "stored" in a table of similar results for the previous hundred days. This table is then "processed" to calculate any significant trend in say hourly levels or peak levels or perhaps summarised by weeks or lunar periods, whichever may be appropriate.

In turn the results of this "processing" would be "output."

Similarly, the details of a purchase would be "input" for processing; details of the debtors account may be retrieved from "storage": an invoice calculated ("processed") and output." and the updated (processed) debtors account returned to "storage."

It is, of course, the "processor" that performs all the computing functions of the system.

Let's see how it works.

There are three essential functions of the pressor to be examined.

a. Processor storage.

b. Control.

c. Arithmetic.

The processor storage is somewhat different to the main storage component of the computer system. To differentiate between them I will now refer to core storage (or immediate access storage) in the processor and file store (or backing storage in the overall system. Core storage derives its name from its principal element, the magnetic core, which is a tiny ring of ferrite. Thousands of these are wired together to form a storage device capable of accepting or delivering information in a few millionths of a second.

Groups of cores are systematically organised into "words" each capable of being addressed by the processors control unit, and each capable of storing information. A comparison can be made with a set of pigeon-holes. A whole set is a storage device, a single pigeon-hole is a "word" of storage located at a fixed position within the device.

Processor storage diagram

Processor storage has two functions, first, to store a series of instructions and second to store the information or data to be immediately processed. The instructions for any computation are described collectively as the programme, and programming or the preparing of computer instructions as described in a later paragraph.

Diagrammatically then, the processor may be represented as a set of pigeon-holes (or words", a control device and an arithmetic device.

An instruction to a computer usually has three elements:

1. the function or operation, e.g. add, subtract, move.

2. the "from" word or operand.

3. the "to" word or operand.

An example would be:

Add the contents of word 50 (x) to the contents of word 76 (y).

The control device analyses each instruction and directs the data stored in the operand words to or from the arithmetic device.

When an instruction is executed the control device then reads the next instruction in sequence for analysis and execution.

An important feature of a computer is its, logical capability. This is derived from the facility to take alternative sequences of instructions depending on the results of; previous calculations: e.g. if word A is negative take the next instruction from word 32. otherwise take next instruction from word 43.

The arithmetic unit of the modern computer is capable of much more than simple; addition and subtraction. Most machines can perform logical arithmetic and operate in binary, decimal or other bases at will. If the arithmetic unit does not have the facility built in then almost certainly it can be programmed.

The control unit also has the important function of communication with input, output and storage devices on instruction.

Input devices

There is nowadays a wide choice of equipment for getting Information into a computer.

The most popular are punched card or paper tape readers capable of reading information at rates of over 1000 characters per second. Magnetic ink character recognition is used for banking and financial applications, and optical character recognition is now a practical reality. A tremendous amount of research is being applied to the machine reading of handwriting and to voice recognition.

There are many devices available for translatnig analogue data meter readings directly into acceptable digital form.

In all cases, the "reader simply converts Information to a standard form and loads the data into the core storage of the processor.

Output devices

The most common forms of computer output are printed paper and punched cards or paper tape.

But of note are developments in graph plotters, television style display terminals and voice communication, all of which are commercially available but comparatively expensive.

Printers used in New Zealand vary in speed from 10 characters per second to 3600 characters per second.

In all cases, Information from the core storage of the processor is simply transmitted to the output device by the control unit directed by an instruction: e.g. print from word 66 to printer number 1.

It is important to appreciate that the formal or layout of the printed output is completely under the control of the programme and it is not uncommon for the same computer to. say. print monthly statements of account, and immediately produce comparative analyses of financial results in graphical form when the statement run is complete.

Storage devices

All common forms of backing storage record data on a moving magnetic surface.

Magnetic tape stores Information in a serial form rather like the familiar tape recorder. It has the advantage of being cheap and relatively fast with speeds of reading or writing ranging from 15.000 to 300.000 characters per second.

A reel of half-inch wide tape 2400ft long kept on a reel less than 12in in diameter can Store about 16 million characters of information. A disadvantage is that input Information must be sorted to the same sequence as that stored on the magnetic tape. Also all information stored on magnetic tape must be processed whether there are changes or not.

Magnetic drums have a surface coated with magnetic material. Information is stored in bands on the surface while the drum revolves at high speed. Each band has a read-write head and information can be read or written at speeds or up to 1.200.000 characters per second selected from any band at will. The limitation is that restricted amounts of inhumation can be stored and the cost per unit of information stored is quite high.

Magnetic disc storage is a compromise that offers the advantages of random access and rapid rates of reading and writing but requiring some time to locate the information area to be accessed. In recent years random access storage devices have been developed tremendously and can now compete in price with magnetic tape.

Interchangeable disc units which can store about 25 million characters, each accessible In less than 1 10th of a second, are now available while fixed disc units can now access information in less than 1 100th of a second. Once the information is accessed, transfer takes place at speeds of up to 300.000 characters per second.

Programming

The great power of the modern computer lies in its versatility.

A programme can be loaded into the processor stoiage extremely rapidly and to switch from preparing a payroll to. say. a programme for performing structural stress analyses, can be achieved in a few seconds. This, of course, eon happen only when the programme to perform the desired task has been properly prepared.

Programme preparation, programme writing or programming, as it is usually described, is the operation of assembling a series of computer instructions in the correct sequence to perform a specific pre-defined task. This is usually achieved by establishing a logical, pattern of decisions and calculations, which, when expressed diagrammatically form a flow chart or block diagram. When the logic of the operation is checked from the diagram. each step is translated into computer inslructions. Although a computer may operate internally in, say, binary rotation, the programmer of today need not be concerned. He writes his programme in a language which almost English, and although varying from machine to machine would look something like this:

Zad Income, Taxable

Mult Taxable, @ 60 #, Result

Call Pensterl, Result, Tax

Which if translated would mean:

Clear to zero and add to. an accumulator, called "Taxable", the value stored in "Income";

Multiply the now content of "Taxable" by the number "60", and store the product in "Result";

Call (execute) a subroutine named Pensterl (which converts pence to sterling) using the value (in pence) stored in "Taxable" and store the terling lesult in area named TAX.

When the programme is written It is punched into cards and fed into the computer for translation or assembly into compute language. The cards punched for translation are described as the "source'' programme and alter translation the computer outputs the "object" programme, which when. in turn loaded Into the computer will process the date for which the programme was written.

The sequence of events might be as follows:

1. Write the source programme and punch into cards (input).

2. Process as data using an assemble) programme.

3. Output the assembled object programme on punched cards.

4. Load the object programme into the computer.

5. Process user data to achieve desired results.

6. For subsequent processing, repeat steps 4 and 5.

This type of programming is described as machine oriented because most instructions written are similar to those actually performed in the machine. Mast of the programming in New Zealand today is performed with this type of language. While it is relatively slow to write, the final result is efficient in operation.

An important development of recent years has been that of report prom amine generators.

Essentially, a programme generator consists of a standard programme which is modified by the programmers parameters, which in general describe the input layout, the information to be processed, the calculations to be performed, and format of the output. The parameters for a simple Job can be written in minutes, and since 30-50 per cent of all programmes for commercial work are basically simple, it can be appreciated that this form of programming is very popular.

Scientific applications for computers can be implemented with a programming language known as Fortran—a contraction of Formula Translation — in which arithmetic and logical functions are described in almost standard mathematical form. An interesting and important feature of this language is that it has become almost universal. A programme in this language can be used with little or no modification on a wide variety of models and makes of computer.

The people who are making careers in the rapidly growing data processing field in New Zealand have a wide variety of background, education and experience. It is significant that a very high proportion have university qualifications, and perhaps surprising, that nearly every degree and specialisation is represented: Accountants and Mathematicians certainly. Engineers marine, electrical. chemical, mechanical and civil: graduates in languages, Geography, Economics, Psychology, History, English and Political Science: and of course the sciences. The common factor is an aptitude for logical, practical, and constructive thinking. This aptitude is by no means restricted to graduates and many people have found an absorbing and satisfying career in data processing.

It would be impossible in this article to describe the many career opportunities in the computer industry but in New Zealand most people are engaged in applying the computer to New Zealand business or scientific requirements. Overseas the design and manufacture ,of new computers and new devices challenges, thousands of highly skilled and experienced men and women. Perhaps one of the least publicised professions is that of "software" development, In which programmes are developed which simplify the using of the computer. The "software" facilties provided with the modern computer are considered to be equally as important as the "hardware" or equipment which uses them.

In this brief review of electronic data processing in New Zealand their has been little opportunity to describe the new developments and trends on a broader scale, The next five years promise ignificant advances in technology.

Significant, too. will be the wav in which the skill and experience of New Zealand computer users will benefit the productivity of this country.