# Lesson Notes By Weeks and Term - Senior Secondary 3

Data representation

Term: 2nd Term

Week: 6

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 2 periods each

Date:

Subject:      Computer studies and ICT

Topic:-       Data representation

SPECIFIC OBJECTIVES:

At the end of the lesson, pupils should be able to

1. Define data representation
2. List and discuss the different data representation methods

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, pictures, Data Processing for senior Secondary Education by Hiit Plc, WAPB Computer Studies for Senior Secondary III by Adekunle et al, On-line Materials.

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher reviews the previous lesson on performing basic operations on binary numbers Students pay attention STEP 2 EXPLANATION He explains the meaning of data representation Students pay attention and participates STEP 3 DEMONSTRATION He then lists and discusses the various methods of data representation Students pay attention and participate STEP 4 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

DATA REPRESENTATION

Data representation can be defined as the way data is being represented in a physical storage medium.

Different computer storage medium stores data differently. Also different data transmission medium transmits data differently.

DESCRIPTION OF DATA REPRESENTATION METHODS

Data representation refers to the methods used internally to represent information stored in a computer. Computer stores different types of information such as: Numbers, text, graphics of many varieties (still, video, animations), sound.

1. Bits:  In a computer system all types of information are stored internally in the same simple format i.e. a sequence of 0’s and 1’s. This is called a BIT. A bit means Binary digit which is represented by an either a zero or a one. Therefore the computer stores all our forms of information stored on it be it pictures, videos, numbers or alphabets in only 0s and 1s.

1. BCD

BCD means Binary Coded Decimal is a digital encoding method for decimal numbers in which each digits is represented by its own binary sequence. In BCD a numeral is usually represented by four bits which, in general represent the decimal range from 0 through 9.

1. EBCDIC

Extended Binary Coded decimal Interchange Code. Is a character encoding set used by IBM Mainframes. EBCDIC uses the full 8bits available to it, which is also known as a byte. It consist of 256 8-bits characters and are used for data representation and transfer. It also used to represent numbers and text.

ASCII

Text can be represented easily by assigning a unique numeric value for each symbol used in the text. For example the widely used ASCII code defines 128 different symbols (all character found on a standard keyboard, plus a few extra) and assigns to each a unique numeric code between 0 and 127.

Computer Character Sets

Computer character sets is a defined list of characters recognized by the computer hardware and software. It is the set of characters represented in different data representation method. Each character is represented by a number.

The ASCII character set, for example, uses the number 0 through 127 to represent all English characters as well and special control characters.

EVALUATION:    1. Define data representation

1. List and explain the different methods of data                    representation

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively