2.1 System Concept

2.0 COMPUTER SYSTEMS

SUB TOPICS 2.1 2.2 2.3 2.4 2.5

SYSTEMS CONCEPT HARDWARE SOFTWARE INSTALLATION CURRENT AND FUTURE DEVELOPMENTS

2.1

SYSTEM CONCEPT

2.1.1 2.1.2 2.1.3 2.1.4

Overview of Computer Systems Data Representation Introduction to Binary Coding Data Measurement

2.1.1 Overview of Computer Systems

Definition of ….. Computer 

An electronic device that accepts data (input) and processes it into useful information (output)

System 

A set of related parts that operate together to perform specific function.

Computer System A system which uses devices that can store and process to perform specific function. 2.1.1

Overview of Computer Systems

A computer system requires four main aspects of data handling :

Input 

Raw data that is put into the computer system for processing through input device.

Processor



An electronic circuitry which interprets and carries out the basic instructions that operate the computer. Also called CPU. 2.1.1

Output 

Raw data that has been processed by the computer into usable information through output device.

Storage 

A device that holds data, information and instructions for future use.

Overview of Computer Systems

Information Processing Cycle Input

Data

Process Informatio n Data Informatio n

Storage

Information

Output

Information Processing Cycle 





Computers process data ( input ) into information ( output ). A computer often holds data, information and instructions in storage for future use. Instructions are the steps that tell the computer how to perform a particular task.

2.1.1

Overview of Computer Systems

2.1.2 Data Representation

DATA REPRESENTATION   

Computer communicates using digital form which are ON and OFF. Binary system consists of only two digits, 0 and 1. In the computer, 0 is used to represent the electronic state of ON and

1 is used to represent the electronic state of OFF.

BIT

BYTE

CHARACTER

Basic units for storing data in computer memory A binary digit ( 0 and 1 )

8 bits that are group together as a unit Used to represent numbers, letters and special character A number, letter, punctuation mark or other symbol that is represented by a single byte in the ASCII

2.1.2 Data Representation

2.1.3 Introduction To Binary Coding

What is ASCII code? 





Stands for American Standard Code for Information Interchange The most widely used binary code to represent data. A coding scheme using seven-bit characters to represent data characters

2.1.3

Introduction to Binary Coding

Example of ASCII scheme ASCII

CHARACTER

00110000

0

00110001

1

00110010

2

00110011

3

00110100

4

00110101

5

01000001

A

01000010

B

01000011

C

01000100

D

2.1.3

Introduction to Binary Coding

What is the function of ASCII code? 





To communicate with the computer, we use a common scheme for data representation. There must be agreement on which groups of bits represent which characters. ASCII makes human interaction with computer possible.

2.1.3

Introduction to Binary Coding

2.1.4 Data Measurement

Data Measurement The size of data is measured by the number of bytes TERM Bit Byte

ABBREVIATION

APPROXIMATE SIZE (byte)

EXACT SIZE (byte)

Bit is the basic unit for storing data in computer memory ( 0 and 1). B

1

1

Kilobyte

KB

1,000

1024

Megabyte

MB

1,000,000

1,048,576

Gigabyte

GB

1,000,000,000

1,073,741,824

Terabyte

TB

1,000,000,000,000

1,099,511,627,776

2.1.4 Data Measurement

2.1.5 Clock Speed Measurement

Clock Speed Measurement   

Pace of the system clock, measured by the number of ticks per second. The faster the clock the more instructions can be executed by the processor. Clock is measured in Megahertz (MHz) or Gigahertz (GHz)

TERM

ABBREVIATION

APPROXIMATE SIZE ( ticks per second )

Megahertz

MHz

1,000,000

Gigahertz

GHz

1,000,000,000

2.1.5 Data Measurement