Computersight -

Most operators of computers are non technicle people. The typical operator will know how to start the computer, log on if neccessary, and then get into the program they usually run. They are interested in the computer to get a job done and are not too conserned how this happens (as long as the computer keeps working!). This will involve getting familiar with the software and hardware aspects they need to know about. The rest of the system exists, but if it does not impinge on the job they have to do, little needs to be learnt about it. As students of computers we will need a deeper level of understanding than this, we need more insite into what is going on inside these machines that are now such an integral part of our lives.

Our investigation however, while making us more familiar with computers, will still remain generalised. Computer systems are developing so rapidly that what was learnt five years ago may well be out of date now. Our look at computer systems will not concentrate too much on the detail of specific computers or software other than to give us some idea of what is involved. It is more important to gain an oversight of the general aspects of all systems so that our knowlege is adaptable to new ideas as they arise.

The human perspective is also important. Computers are tools used by people to do a job. We will keep this in mind as we study all aspects of systems. Without looking at the people who use and control the computers we will gain only a one dimensional view of computer systems.

Our goal is to be able to be self reliant and exert control over the systems we come into contact with. To do this we are going to develop our knowledge and understanding of computer systems so that we can play the role of a systems analyst and system designer.

2.0 A Computerised Information System

2.1 Systems

A working computer setup is not just a collection of components it is a system – but what is a system?

Think of some of the systems you may know of (e.g. the digestive system, the education system, a stereo system) – what makes them a system?

A system is a group of componants that work together toward a common purpose. As an example your digestive system consists of mouth and teeth, oesophagus, stomach, intestines etc. that work together to convert complex foods to simple sugars that can be carried by the blood.

In some systems the goal is to convert input to a required output.

The education system takes young people, teachers, books etc. in, and outputs educated, knowlegable, well informed individuals (well, that’s the idea anyway). A computer system is similar – data is input, processed in some way to produce an output of information. Information is data organised in a meaningful way. Nowadays we talk about computers as being a part of an information system.

In the past a study of computer systems has concentrated purely on the hardware, but this view is too limited. We really need to understand the whole environement that the system operates in. This will include the operators, the way operators inter-react with the hardware, work and management systems, the software and operating systems as well as the hardware.

2.2 The Operator

The operator is a general term to describe anyone who interacts with a computer system. The operator can be anyone from a shoper pressing a touch sensitive screen for information, through to a network manager who has control of five hundred terminels.

Each operator of the system, whether it consists of one stand alone PC (personal computer) or hundreds of networked terminals, interacts with the system on a one to one basis. In doing this the operator builds up their own view or mental image of how the system appears to them.

No matter the level of interaction the operator has at some stage to be traned (educated) in how to use the machine. The more casual the approach, the simpler, or more intuitive the learning must be. The best systems are those that are easy to learn, easy to use and are consistant, predictable, fault tolerent, and error free. Each operator becomes capable of handling the aspects of the system they need to get their job done.

2.3 The Operator Interface

Every computer system must provide a shell or interface with the operator. This is the link between person and machine.

The computer works in machine code, a language of components being off or on, usually represented as 0 and 1 e.g. 0011 1101 0011 0101 1010 1101 1100 1111. Operators on the other hand need words or pictures that they can understand to comunicate with and control the computer. The term operator friendly is used to describe how easy it is for the operator to opperate the system through the interface.

There are three main categories of operator interface:

Command driven :  In this the operator types in a letter or a word from the keyboard that is then translated into an instruction the computer carries out. These interfaces are quick to use but are difficult to learn. e.g. MS DOS,  DBase

Menu driven interface :  The operator is given a list of chioces and then types in the letter or number chosen to carry out that task. These are easy to use but are inflecsible in that the operator is restricted to the choices offered. They can also be anoying in attempting to find a specific option in a complicated menu system. e.g. MS-Works, NewsMaster

Graphical operator interface (G.U.I.):  This format consists of a series of pictures (called icons) that represent the various tasks or programs that can be run. The operator points to the required icon using a mouse and clicks to activate it. A GUI is very easy to learn to use but again does not have much flexibility, e.g. Windows, Macintosh O.S.

In addition there are less common interfaces such as natural langage (where the computer can interpret typed or spoken English commands), pen based computing and interfaces such as touch screen

2.4 Ergonomics

Ergonomics is the study of the relationship between a person and their workplace, with the view to providing a safer, more comfortable and productive environment. It is concerned with the practice of fitting the environment to the worker, rather than the older idea of making a worker fit into a given workplace.

Ergonomics in relation to a computer system can take into acount three main areas:

Workplace

light – is there sufficent (300-600 lux); is there glare or flicker; is there a pleasing colour scheme?

noise – is the workplace free of excessive noise (55-65 Db)?

climate – is the temperature comfortable (20-26C) and humidity satisfactory?

space – is the workplace too crowded or cluttered (7-10m per person)?

safety – are there no obvious dangers.

Hardware

keyboard – at a comfortable position; positive feel to keys (15-125g).

screen – angle (5 – 30 degrees) and distance (35-60cm) from eyes suitable; low radiation; clear; colour.

printer – low noise level; legible; reasonable speed.

work station layout – placement of hardware within easy reach; common items closest.

desk – correct height for operator; rounded edges.

chair – posture correct; lumbar support; mobille; foot rests if required.

cabling – unobtrucive.

Software

operator friendly – ease of learning; fault tolerant; on line help.

interface – graphical or menu driven.

ease of use – legebility; use of colour, graphics and sound.

2.5 Work and Management Systems

The work systems are the operations the computer operator carries out in day to day functioning.

These will include:

ways used for data colection,

methods of entering data into the computer,

the setting up a (computerised) file system to suit themselves and the task requirments,

the operator may also be responsible for aspects such as security and maintaining backups of data.

Training is required in all of these areas, and this must be well designed to promote efficiency and still provide worker satisfaction.

Management may involve only a single person, the operator, or in a large organization may be a group of people with specific jobs. Managment can be divided into two aspects: looking after the operators and looking after the hardware and software.

Personnel management involves the training of operators and setting up effective work systems. The health and safety

of workers should be a priority with the removal of hazards, the reduction of stress factors and the use of ergonomic principles in designing the work environment. The overall effectiveness of the system relies on how well the operators are allowed to do their job.

Technical (or system) management is far more wide ranging and in small organisations may involve outside experts being called on to assist.

It includes:

the installation, customisation and maintenence of software and operating systems;

installing, maintaining and updating the hardware;

in a networked situation: the maintenance of operator accounts, record keeping and network file maintenance;

provision of security from tampering with files, the physical protection of the equipment, preserving software copyright and the avoidance of viruses;

involvement in the decisions on which hardware and software to buy initially or during an upgrade, and keeping the system flexible so that it can meet future demands of new requirements or new technology.