Information Systems
An information system is a collection of interacting parts whose purpose is to allow the user or a group of users to locate and interpret information
Environment
The environment is everything that influenced by, the information system and its purpose
Description: The information system has an impact on its environment and in turn the environment has an impact on the information system
Purpose
The purpose is the reason for the creation and existence of the information system.
Description: There are a lot of reasons for the development of information systems – E.g. Client records for a business enterprise
Information Processes
Involve both computer and non-computer activities carried out to develop and maintain an information system.
Collecting
Organising
Analysing
Storing and Retrieving
Processing
Transmitting and Receiving
Displaying
Data/Information
Data is the raw material that information processes deal with. Information is the output from that data once it has been processed and given meaning by people.
Data can take many forms such as graphics, audio, video, text or numbers and its use will be determined by the purpose of the information system.
Participants
Participants are the people who carry out the process within the information system.
They play a direct or indirect role in the development and use of the system.
Information Technology
This is the hardware and the software used in the information system.
Each is dependent on the other for the information system to operate.
The Nature of Data and Information
Data is any individual fact that can be input, stored, processed, output and retrieved from a computer.
Data is the raw facts of an information system and it can be input in many forms
Information is the output from an information system. It is data that has been organised and given meaning by the information processes and participants in the system.
Data + information processes + interpretation by participants = INFORMATION
The purpose of an information system is to provide users with the appropriate kind of information they need for their purpose.
Digital Representation of Data
Data can be represented in digital or analog form.
Analog data is the type of data with which most humans are most comfortable. Analog data can have many states, and measures much smaller units like the tone of a human voice. This data can be varied continuously
Digital data is data that can only be in one of two states like a light switch (in reality, high electric voltage or low electric voltage.)
In most computer systems, data is represented in digital form. A computer system has many electronic circuits, and these can either be ON or OFF.
This binary number system is used to represent the two states.
1 stands for ON
0 stands for OFF
1 and 0 are the only digits…binary system!
Types of Data
Data Type Description Characteristics
Image A static or animated graphic used for illustration or as a substitute of text Photographs, drawings or paintings from which information is obtained. Require more storage space than text
Audio A sound such as noise (beeping) or voice (speech) recognition software which reads text. Music in different formats. Requires specialised hardware (sound ware, speakers). Information is obtained by listening to the sounds
Video A film clip which may also include text, sound and animation. Requires specialised hardware. Uses a large amount of processing and storage space
Text Individual characteristics
Sets of characters called strings Any letter, number, symbol, punctuation mark or white space that can be interpreted by the hardware
A series of characters treated as one unit (a word or a sentence)
Numbers Integers Whole numbers (100, 45, 1045)
Decimals Floating point numbers (6.5, 7.33)
Percentages Parts of a whole (15%)
Currency Money values ($24.10)
Dates Formatted in various ways (2/3/2009)
Bitmapped Graphics
They are paintings or photographic images where dots on the output device are represented by bits in primary storage.
The quality of bit mapped images depends upon the resolution used.
The higher the resolution and the number of colours, the larger the amount of storage used.
Vector Graphics
A vector graphic image is composed of mathematically defined object which can be created from basic shaped called primitives, for example: circle, square or line.
Vector graphics are line drawings which describe an object shape, colour or texture.
Graphic Programs
Graphic programs are classified as paint or draw programs.
A paint program creates a graphic by telling the computer how to display each pixel.
A draw program creates graphics by dividing the picture into a number of objects such as a line, curve or shape.