Introduction to Information Technology
ITEC 1000 – Winter 2010 – Peter Khaiter
Lecture 1 – Information Systems and Technology: Basic Concepts – Jan 4
General Systems Theory
- System’s Concept
o Definition – a system is a set of components that interact with one another
and serve for a common purpose or goal.
o Systems may be abstract or physical.
An abstract system is conceptual, a product of a human mind. That
is, it cannot be seen or pointed to as an existing entity. Social,
theological, cultural systems are abstract systems. None of them
can be photographed, drawn or otherwise physically pictured.
However, they do exist and can be discussed, studied and
A physical system, in contrast, has a material nature. It is based on
material basis rather than on ideas or theoretical notions.
Either system has nine main characteristics:
- System’s Characteristics
o A component is either an irreducible part or an aggregate of parts, also
called a subsystem. The simple concept of a component is very powerful.
For example, in case of an automobile we can repair or upgrade the
system by changing individual components without having to make
changes the entire system.
o The components are interrelated; that is, the function of one is somehow
tied to be function of the others. For example, in the story system the work
of one component, such as producing a daily report of customer orders,
may not progress successfully until the work of another component is
finished, such as sorting customer orders by date of receipt.
o A system has a boundary, within which all of its components are contained
and which establishes the limits of a system, separating it from other
o All of the components work together to achieve some overall purpose: the
system’s reason for existing. o A system operates within an environment – everything outside the
system’s boundary. The environment surrounds the system, both affecting
it and being affected by it. For example, the environment of a university
includes prospective students, foundations, funding agencies and the new
media. Usually the system interacts with its environment. A university
interacts with prospective students by having open houses and recruiting
from local high schools.
o The point at which the system meets its environment are called interface.
o A system must face constraints in its functioning because there are limits
to what it can do and how it can achieve its purpose within its
environment. Some of these constraints are imposed inside the system
(e.g. a limited number of staff available). Others are imposed by the
environment (e.g. due to regulations).
o A system interacts with the environment by means of inputs and outputs.
Input is anything entering the system from the environment; output is
anything leaving the system crossing the boundary to the environment.
Information, energy and material can be both input and output in relation
to the environment. People, for example, take in food, oxygen, and water
from the environment as input. An electrical utility takes on input from the
environment in the form of raw materials (coal, oil, water power, etc.),
requests for electricity from customers. It provides for output to the
environment in the form of electricity.
- Feedback and control in a system
o Feedback – very often output’s data are returned to the input of the
system and used to regulate the system’s activity.
It helps to adjust the system to changes so that the system
operates in a balanced state, or equilibrium. Large hotels and
motels, for instance, ask guests to fill out cards evaluating the
services. This feature of a system is used in control.
o Control is the process that measures performance and guides it toward a
o Negative feedback is corrective feedback that helps maintain the system
within a critical operating range and reduces performance fluctuations
around the norm or standard. Negative feedback is transmitted in
feedback control loops. A sensor detects the effect of output on the
external environment; this information is returned to the system as input,
and necessary adjustments are made according to predetermined goal.
o In contrast to negative feedback, which is corrective, positive feedback
reinforces the operation of a system by causing it to continue its
performance and activities without changes.
- Methods of a system’s study
o There are several important system’s concepts that help to study a system
and understand its functioning:
o Decomposition is the process of breaking down a system into its smaller
components. These components may themselves be systems
(subsystems) and can be broken down into their components as well.
o Modularity is a direct result of decomposition. It refers to dividing a system
into chunks or modules of a relatively uniform size. Modules can represent
a system simply, making it easier to redesign and rebuild.
o Coupling means that subsystems are dependent on each other. But they
should be as independent as possible. If one subsystem fails and other
subsystems are highly dependent on it, the others will either fail
themselves or have problems functioning.
o Cohesion is the extent to which a subsystem performs a single function.
- ‘Systems’ thinking
o Being able to identify something as a system.
o Being able to identify subsystems.
o Identifying system characteristics and functions.
o Identifying where the boundaries are (or should be).
o Identifying inputs and outputs to systems.
o Identifying relationships among subsystems.
Information Systems and Technology
- Information system, subsystem and supersystem.
o Both control and management have an informational nature, that is among
all the possible inputs and outputs (information, energy and matter) they
use the only one – information. Information is the central core of all
resources in feedback loops while regulating the system activities. Any
organization as a system could not survive without information. They need
to develop a special system for processing and handling the information
o Information – a description of a thing or process.
o Technology – a set of tools with a common purpose.
o Information technology – a set of tools for managing descriptions of things
o Definition – an information system is a collection of interrelated
components that collect, process, store and provide as output the
information needed to complete a business task.
o Alone with the system boundary (i.e. any inputs and outputs) of an IS, we
have to consider the automation boundary – it separates the automated
part of the IS (where work is done by computers) from the manual part
(where work is done by the people).
- Concepts of separation
o Separating data and processes that handle data.
We can consider every IS as a three-component system:
• Data • Data flows
• Processing logic
Data are raw facts that describe people, objects and events in
organization (e.g. names, age, and customer’s account number).
Data is used in an IS to produce information.
Information is data organized in a form that human can interpret.
Data flows are group of data that move and flow through a system.
They include a description of the sources and destinations of each
Processing logic describes the steps that transform the data and
events that trigger these steps.
There are two approaches to IS design:
The process-oriented approach is based on what the system is
supposed to do. The focus is on output and processing logic.
Although the data are important, they are secondary to the
application. Each application contains its own files and data storage
The data-oriented approach is a strategy that focuses on the ideal
organization of data, independent of where and how data are used
within the system. This approach uses data model that describes
the kinds of data needed in the system and the business
relationships among the data (i.