Intro To Computing

What is Computer?

Computer…..

A computer is an electronic device that accepts raw data, processes it according to a set of instructions and required to produce the desired result.

What does a Computer Do?

The operation of every computer can be divided into four basic functions.

Input: Information you put into the computer by way of keyboard, mouse etc.

Processing :Also known as the "Brain" of the computer. Processes the information you put in into human readable form.

Cont……

Output: The information you put into the computer is seen on the monitor screen and can be printers out on paper and is readable.

Storage : Either the computers memory, CD's, DVD's, Floppy Disc's, USB Flash Drives, etc.

INTRODUTON OF COMPUTER C COMMANLY O OPERATED M MACHINE P PURPOSELYU USED FOR T TRAINING E EDUCATION & R RESEARCH

History Of Computers

•Before the 1500s, in Europe, calculations were made with an abacus

Invented around 500BC, available in many cultures (China, Mesopotamia, Japan, Greece, Rome, etc.)

•In 1642, Blaise Pascal (French mathematician, physicist, philosopher) invented a mechanical calculator called the Pascaline

•In 1671, Gottfried von Leibniz (German mathematician, philosopher) extended the Pascaline to do multiplications, divisions, square roots: the Stepped Reckoner

None of these machines had memory, and they required human intervention at each step

• In 1822 Charles Babbage (English mathematician, philosopher), sometimes called the “father of computing” built the Difference Engine

• Machine designed to automate the computation (tabulation) of polynomial functions (which are known to be good approximations of many useful functions)– Based on the “method of finite difference”– Implements some storage

• In 1833 Babbage designed the Analytical Engine, but he died before he could build it– It was built after his death, powered by

steam

HISTORY OF COMPUTERSYEAR NAME OF

INVENTOR NATIONALITY DEVICE /

MACHINE1.

5000 B.C

ABACUS CHINESE ABACUS

2. 1642

BLAISE PASCAL

FRENCH MECHANICAL, CALCULATING & MACHINE.

3. 1830

CHARLES BABBAGE

ENGLISH MATHEMATICIAN (U.S.)

MECHANICAL, DIGITAL COMPUTER, ANALYITICAL ENGINE.

Components of Computer

Hardware Components Software Components

Hardware Components

The term hardware refers to the physicalcomponents of your computer such as the system unit, mouse, keyboard, monitor etc.Simply We Can sayo Input Deviceso Output Deviceso Storage Deviceso RAMo ROM

Software Components

The software is the instructions that makes the computer work. Software is held either on your computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required.

Input Devices "How to tell it what to do“

A keyboard and mouse are the standard way to interact with the computer. Other devices include scanner, Tracker Ball, Touch Pads, Joystick.

Output Devices "How it shows you what it is doing"

The monitor (the screen) is how the computer sends information back to you. Other Devices includes Printers, LCD Screens, Plotters, Speakers.

Storage Devices "How it saves data and programs“

Hard disk drives are an internal, higher capacity drive which also stores the operating system which runs when you power on the computer.

RAM

RAM stands for Random Access Memory. It is the part of main memory where data and program

instructions are held while being manipulated or executed [44].

It is also known as Read and Write Memory. It is a volatile (temporary) memory of computer

system and stores the data as long as the computer is on.

Once the computer is turned off, the contents (data) of the RAM are washed out. RAM is divided into two categories

RAM Categories DRAM

DRAM stands for Dynamic Random Access Memory. It is combination of cells that store data as charge on capacitors. It is simpler and smaller but storage capacity is high and hence used for large memory requirements.

SRAM SRAM stands for Static Random Access Memory. In SRAM, binary values are stored using traditional flip-flops logic-gate configuration. It is faster then DRAM but its storage capacity is less.

ROM

ROM stands for Read Only Memory. As the name implies, the contents of ROM can only be read. Data cannot be written into read-only memory. ROM may contain the information on how to start the computer and even instructions to the entire operating system

It is a permanent memory of computer and user cannot change it contents

Processing Unit(CPU Hardware Component)

The processing unit is the most important and powerful part of computer system. It is the heart of computer system. All calculations and other operations are performed in this unit

Functions of Processing Unit

Accepts data or instructions from input unit and stores them in memory.

Stores intermediate and final result of processing. Interprets (translate) or manipulate the instruction

and send commands to relevant units. Does all arithmetic operations on the data i.e.

addition, subtraction, multiplication, division etc. Does all logical and decision-making operations on

data, i.e. comparison of data. Sends the result to the output devices when required.

Central Processing Unit -CPU Consist of CU (control Unit) ALU (Arithmetic & logic Unit) Registers

Control Unit It is the most important part of the CPU. It controls and

coordinates the activities of all other units. It performs this function by issuing necessary commands to various components of the computer.

The control unit fetches an instruction from the main memory by sending an address to main memory, decode this instruction and then execute it. Thus we can say that CU’s function is to fetch, decode and then finally execute the instructions, which are in main memory.

OR The control unit interprets any instructions it receives

from memory and directs the sequence of events necessary to execute each instruction. The control unit also establishes the timing of these events.

Arithmetic and logic unit All the arithmetical and logical activities are

performed in the ALU. It is the place where all calculations are performed and all decisions are made. The data is temporarily transferred to ALU for processing and results are sent back to memory.

The ALU perform all the arithmetic operations such as Addition, Subtraction, Multiplication or Division and Logic operations such as the operations in which first comparison is made and then decision is taken

Registers

The processor contains special storage locations called registers. These are temporary storage devices and all the data is temporarily stored in them before and after processing.

How Computer Memory Measured?

BitAll computers work on a binary Numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit.o ByteA byte consist of 8 bits.o KilobyteA Kilobyte(KB) consists of 1024 byteso MegabyteA Megabyte (MB) consists of 1024 Kilobyteso GigabyteA Gigabyte (GB) consists of 1024 Megabyteso TerabyteA Terabyte Consist of 1024 Gigabytes

How Does a Computer Know what to do?

It must be given a detailed list of instructions, called a compute program or software, that tells it exactly what to do.

Before processing a specific job, the computer program corresponding to that job must be stored in memory.

Once the program is stored in memory the compute can start the operation by executing the program instructions one after the other.