Output involves the presentation or display of information to a person, or
the transfer of data to another computer. Common output devices are the
computer screen and the printer. The information presented is the result of a
participant’s work on the computer.
All the functions of computer hardware work together. Data is entered using
an input device and is processed in some way before being presented using an
output device. The computer’s power comes from its ability to perform these
functions with speed, accuracy and reliability. The concepts of input, process,
storage, control and output are used in a huge range of computers. They are
often classified according to their power and capabilities as: personal computers,
midrange computers, mainframes and supercomputers.
• A personal computer (PC, also known as a microcomputer) is a single-user
computer that generally sits on a desktop. Portable computers such as laptops,
notebooks and palmtops are also classified as personal computers. PCs
are suitable for individuals’ needs, such as word processing, spreadsheets and
graphics. In organisations, they can be joined together to form a network.
• A midrange computer or minicomputer is a central computer that performs
the processing for a number of users working at terminals. A terminal is an
input/output device (usually a keyboard and screen). Midrange computers
are typically used for accounting, database management and specific industry
applications.
Amainframe computer is a central computer for a large number of users. It is
more powerful than a midrange computer and often has thousands of
terminals connected to it. Mainframe applications include payroll computations,
accounting and airline seat reservations.
• A supercomputer is the fastest,most powerful and expensive type of computer
(see Figure 1.5). Supercomputers are designed for applications requiring
high-volume and high-speed calculations, such as simulations of the weather
and aerodynamics design.
Advances in technology have blurred the differences between these types of
computers. Today’s PCs use similar microprocessors to both mainframes and
midrange computers. However, using PCs for a mainframe-type application
requires the PCs to be linked in a network. While midrange and mainframe
computers are designed to accept input from multiple users simultaneously, PCs
do not support this type of application.
Software
Software is the detailed instructions (computer programs) used to direct the
hardware to perform a particular task.A computer needs software to tell it what
to do and it needs hardware to carry out the actual work. There are two main
types of software: application software and system software.
• Application software is a computer program used for a specific task. It allows
the computer to achieve the task for which it was designed. Application
software includes word processors, databases, graphics programs and
spreadsheets.
• System software manages and controls the hardware so the application
software can perform the required task. It determines the way the participant
interacts with the information system. System software includes operating
systems and utility software.
Data and information
Data is the raw material entered into an information system. This raw material
could be in the form of images, audio, video, text or numbers, and is entered
using an input device. Data may or may not be relevant or useful for a particular
task. A key role for an information system is to process data into information.
(Although the word ‘data’ is the plural of datum, it is widely used as both a
singular and a plural.)
Information is data that has been ordered and given some meaning by
people. It is created or modified by the information processes. The form and
content of information must be appropriate for a particular use. It is used within
the information system or is the result of the information system. (Data and
information are discussed in more detail in section 1.4.)
Participants
Participants are the people who carry out the information processes within the
information system. They are the people who do the work. Participants need to
know what to do, how to do it and when to do it. All information systems have
participants—even the most automated systems rely on people if the system
fails. Participants have an essential role in an information system, and the success
or failure of the system depends on their skills, interests and commitment.
Participants are often referred to as direct users, or simply users. They
interact with, or are in control of, the information technology (see Figure 1.6).
For example, when you use a word processor to write a letter, you are a participant
in an information system. Participants have different levels of skills, from
the novice experimenting with software to system specialists. System specialists
include people such as managers and operators. Managers oversee the information
system and ensure that personnel and machines are working efficiently.
Operators look after the information technology resources. In addition to participants
(direct users), there are also indirect users. Indirect users, such as
customers, are not part of the system, but it is their needs that form part of the
purpose of the system.
Although information systems affect participants, the systems are often designed
with little regard for them. The nature of the impact depends on the
individual characteristics of the participant. People come from different backgrounds
and have different levels of expertise. Some participants may be able to
work in a very structured environment and complete repetitive tasks, while
other people will find this unsatisfactory. For example, the introduction of new
technology may provide a more challenging job and an opportunity to learn new
skills. On the other hand, it might deskill a participant’s job and make it boring.