computer system overview

COMPUTER

OVERVIEW

WHAT IS A COMPUTER???????????

• A computer is an electronic device that can perform many operations in accordance with a set of instructions called program..

FUNCTIONAL COMPONENTS OF A COMPUTER

INPUT UNIT CPU

(Central Processing Unit)

OUTPUT UNIT

THE MEMORYArithmetic Logic

Unit (ALU)

Control Unit(CU)

• Input Unit• convert data and instructions into electronic form for input into the computer.• E.g.: Keyboard, mouse, OMR(Optical Mark Reader)etc.

• Output Unit • convert electronic data produced by the computer system and display them in a form that people can understand.• E.g.: printer, plotter, VDU(Visual Display Unit), etc.

• The CPU • manipulates raw data into

more useful form and controls the other parts of the computer system.

• The ALU performs the computer’s principal logical and arithmetic operations.

• The CONTROL UNIT coordinates and controls the other parts of the computer system.

• The Memory• A memory cell can be

defined as a device which can store a symbol selected from a set of symbols.• Unit of memory is byte.• 1byte = 8bits

HARDWARE-it refers to the tangible parts that make up the computer system.

Hardware consists of 5 primary components:

INPUT DEVICES

CPU

MEMORY

OUTPUT DEVICES

STORAGE DEVICES

SOFTWARE-it refers to the set of programs of a computer system.

Software is classified into 3 categories:

OPERATING SYSTEM

LANGUAGE PROCESSOR

APPLICATION SYSTEM

Operating System is a program which acts as an interface between a user and the hardware and controls all other components of the computer system.Examples: Windows, Linux, Unix and Mac OS, etc.,

• Computer System consists of:

1. The hardware2. The operating system3. The application

software4. The human ware(users)

FUNCTIONS OF OS:

1. Manages and Interacts with Computer Hardware2. Provides and Manages System Security3. Provides the System Interface4. Provides the Interface for Application Software5. Program creation6. Program execution7. Input/output operations8. Error detection9. Resource allocation10.Protection

• Language processors are given below:i. Assembler: converts program written in

assembly language to machine language.ii. Interpreter: converts a HLL program to machine

language by converting and executing it line by line.

iii. Compiler: converts the HLL program to machine language by converting it in one go and report all the errors by line.

Since a computer cannot understand the language other than machine language therefore it becomes necessary to process a HLL program to make it understandable. This job is performed by Language Processors.Examples: FORTRAN, C++, java, COBOL, etc.,

Application Software is a set of programs necessary to carry out operations for a specified application.

• Customised Application software: it is developed to meet all the requirements specified by the user. However it cannot be directly installed on any other computer as the requirement may differ.• General Application software: it is

developed by keeping all the general requirements in mind required to carry out a specific task.

Strength and Weakness of computers:

StrengthI. SpeedII. High storageIII. AccuracyIV. ReliabilityV. versatility

WeaknessI. Lack of decision

of power makingII. IQ zero

EVOLUTION OF COMPUTERS

1. ABACUS(3000BC)2. NAPIER’ S LOGS AND BONES(1662)3. PASCALS ADDING MACHINE(1642)4. LEIBNITZ COMPUTER(1671)5. JACQUARDS LOOM(1801)6. BABBAGES DIFFERENCE ENGINE(1822)7. BABBAGES ANALYTICAL ENGINE(1833)8. HOLLERITHS MACHINE(1887)9. MARK-1(1943)

GENERATION OF

COMPUTERS

3RD GENERATION

4TH GENERATION

5TH GENERATION

THE FIRST GENERATIONS COMPUTER

• ENIAC(1946)-----------

• EDVAC(1950)----------

• EDSAC(1949)----------

• UNIVAC-1(1951)------

• Electronic Numerical Integrator And Calculator

• Electronic Discrete Variable Automatic Computer

• Electronic Delay Storage Automatic Computer

ENIAC

EDVAC

EDSAC

UNIVAC

THE SECOND GENERATION COMPUTERS• KEY FEATURES OF SAME:1. Transistor replaced vacuum tube2. Smaller compared to 1st generation3. Generate less heat4. Low electricity consumption5. More reliable and faster6. Core memory developed7. Magnetic tapes and disks used8. First operating systems developed

Lists of some second generation computers::::

Model Size Area of application

IBM 1401 Small to medium Business

IBM 1620 Small Scientific

IBM 7094 Large Scientific and business

CDC 1604 Medium to Large Scientific

CDC 3600 Large Scientific

RCA 501 Medium Business

UNIVAC 1108 Large Scientific and business

AND SO ON………………….TILL 5TH GENERATION

THANK YOU

SEERAT &&&& TANIYA