What is Data
Data is a stream of raw facts representing things
or events that have happened.
In ICT, we usually say that data is made up from
four basic types:
Inside the computer, however, all data is stored as
• Numbers – are stored as numbers, obviously!
• Text characters are stored as a code that represents each –
• Images are stored as numbers representing the amounts of
red, green and blue for each pixel
• Sounds are stored as numbers representing the loudness at
How are the numbers represented
All data types are transformed into a uniform
representation when they are stored in a computer
and transformed back to their original form when
retrieved. This universal representation is called a
Bits and Bytes
• Each of the 0s and 1s is called a bit – binary
• Eight bits together form a byte
• The longest number a computer can handle in
one go is called a word – e.g. a 32-bit computer
has a 32-bit word length
• 1024 bytes is a kilobyte, 1024 kilobytes is a
megabyte, 1024 megabytes is a gigabyte, etc.
A number is changed to the binary system before being
stored in the computer memory. For e.g. 39 is stored as:
Binary equivalent of 39 is : 100111
A section of text in any language is a sequence of symbols
used to represent an idea in that language.
To store text and symbols we use the ASCII codes which
is further coded to binary equivalent.
For example: Text such as “CATS”, which is made up from four
symbols, can be represented as four n-bit patterns, each pattern
defining a single symbol and having certain numeric value in
Audio is not countable and Continuous data, Audio is an
example of analog data.
For audio we select only a finite number of points on the
analog signal, measure their values, and record them, this
records are known as sample.
The quantized sample values need to be encoded as bit
patterns, to store in computer memory.
Images are stored in computers using two
different techniques: Raster graphics and Vector
These graphics are stored in form of Pixel, Pixel
is picture element.
To store Pixel there be a certain bit pattern.
• Information is data that has been processed to make it
meaningful and useful
• Data + Meaning = Information
• For storing Information in digital organization we
require a tool called database.
A centralized and structured set of data stored on a
The database provides facilities for retrieving, adding,
modifying and deleting the data when required.
A database is usually managed by a Database
Traditional Database are organized by fields, records
Without data and the ability to
process it, an organization
could not successfully
complete most business
Data consists of raw facts
For data to be transformed
into useful information, it
must first be organized in a
Digital Information Systems
Digital information system (DIS): single set of hardware, software,
databases, telecommunications, people, and procedures configured to collect,
manipulate, store, and process data into information
– Hardware: computer equipment used to perform input, processing, and
– Software: computer programs that govern the operation of the computer
– Database: organized collection of facts and information
– Telecommunications: electronic transmission of signals for
– Networks: connect computers and equipment in a building, around the
country, and around the world
Business Information Systems
Most common types of information systems used in
E-commerce: any business transaction executed electronically
Transaction processing system (TPS): organized collection of
people, software, databases, and devices used to record
completed business transactions
Management Information Systems (MIS): provide routine
information to managers and decision makers
Decision support system (DSS) : used to support problemspecific decision making