Computer Knowledge

 What is a Computer?

Computer: A Computer is a General-purpose machine, commonly consisting of digital circuitry, that accepts (inputs), stores, manipulates, and generates (outputs) data as numbers, text, graphics, voice, video files, or electrical signals, in accordance with instructions called a program.

• Father of the computer – Charles Babbage.
• Father of the modern computer – Alan Turing.
• Basic Architecture of Computer: John Von Neumann (1947-49).
• First Programmer: Lady Ada Lovelace (1880).
• First Electronic Computer: ENIAC (1946) – J.P. Eckert & J.W. Mauchly.
• The first computer for the home user introduced – IBM in 1981.

Full form of Computer:

• C – Commonly
• O – Operated                     
• M – Machine
• P – Particularly
• U – Used for
• T – Technical
• E-Education
• R – Research

Characteristics of Computer

    

• Speed
• Accuracy
• Storage
• Diligence
• Versatility
• Automation

Computer – An Introduction

• A computer is a device that can receive process and store data.
• However, all computers have several parts in common:
• Input devices allow data and commands to the computer (Mouse, Keyboard etc.)
• Memory for storing commands and data.
• Central Processing Unit which controls the processing.
• Monitor Process the information in the form of output.

Desktop computers

1. Desktop computers design is made for use at a desk or table.
2. They are typically larger and more powerful than other types of personal computers.
3. The main component, called the system unit, is usually a rectangular case that sits on or underneath a desk.
4. Other components, such as the monitor, mouse, and keyboard, connect to the system unit.

Laptops

1. The Laptops are lightweight mobile PCs with a thin screen.
2. Laptops can operate on batteries, so you can take them anywhere.
3. Unlike desktops, laptops combine the CPU, screen, and keyboard in a single case.
4. The screen folds down onto the keyboard when not in use.

Handheld computers (PDA)

1. Handheld computers, also known as personal digital assistants (PDAs), are battery-power computers small enough to carry almost anywhere.
2. These are useful for scheduling appointments, storing addresses and phone numbers, and playing games.
3. Some have advanced capabilities, such as making telephone calls or accessing the Internet.
4. Instead of keyboards, handheld computers have touch screens that you use with your finger.

Peripheral Devices

1. The peripheral device connects to a computer system to add functionality. Examples are a mouse, keyboard, monitor, printer and scanner.
2. A computer peripheral is a device that connects to a computer but is not part of the core computer architecture.
3. The core elements of a computer are the central processing unit, power supply, motherboard and the computer case that contains those three components.

Types of Peripheral Devices

• There are many peripheral devices, but they fall into three general categories:
• Input devices, such as a mouse and a keyboard
• Output devices, such as a monitor and a printer
• Storage devices, such as a hard drive or flash drive

Hardware

• Computer hardware is what you can physically touch includes the computer case, monitor, keyboard, and mouse.
• It also includes all the parts inside the computer case, such as the hard disk drive, motherboard, video card, and many others.

Input Devices

• In computing, an input device is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system.
• It will control devices such as a computer or information appliance.

Examples: keyboards, mice, scanners, digital cameras and joysticks.

Keyboard

• A Keyboard is the most fundamental input device for any computer system.
• It helps to enter data on the computer.
• The computer keyboard is to enter text information into the computer.
• The main use of the keyboard is to type commands directing the computer to perform certain actions.

Mouse

• A mouse is used to input data by sending a signal to the computer, based on hovering the cursor and selecting with the left mouse button.
• The left mouse acts as an ‘enter’ button. The right mouse button can be selected and will often pop up a window of choices.
• The scrolling wheel is used to move the view of the screen up or down.
• By moving your mouse to a location in a document, on a digital photo or over a choice of music, you can click the left mouse button to place the cursor.

Trackball

• A trackball is an input device used to enter motion data into computers or other electronic devices.
• It serves the same purpose as a mouse but is designed with a moveable ball on the top, which can be rolled in any direction.
• Instead of moving the whole device, you simply roll the moveable ball on top of the trackball unit with your hand to generate motion input.

Basic Knowledge of Computer – Main Parts of Computer

Barcode reader 

• A barcode reader (or barcode scanner) is an electronic device that can read and output printed barcodes to a computer.
• Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones.

Digital camera 

• A camera which produces digital images that can be stored in a computer and displayed on the screen.

Gamepad 

• The gamepad is a handheld controller for video games.

Joystick

• The joystick is a lever that can be moved in several directions to control the movement of an image on a computer or similar display screen. It mainly used in playing games.

Microphone

• Micro Phone is an instrument for converting sound waves into electrical energy variations which may then be amplified, transmitted, or recorded.

Scanner

• The scanner is a device that scans documents and converts them into digital data.

Webcam

• A webcam is a video camera connected to a computer, allowing its images to be seen by Internet users.

Optical character recognition (OCR)

• Optical character recognition is the mechanical or electronic conversion of images of typed, handwritten or printed text into machine-encoded text.

Digitizer

• It converts analogue information into digital form.

Optical Mark Reading (OMR)

• Optical Mark Readers reads pencil or pen marks made in pre-defined positions on paper forms as responses to questions or tick list prompts.

Input and Output devices

Input Devices – Computer Knowledge

An input device feeds data to the computer system for processing.

We are going to discuss the most commonly used input devices in this article.

Graphics Tablet

• A graphics tablet consists of an electronic writing area and a special “pen” that works with it.
• A graphics tablet allows creating graphical images with motions and actions.

Computer Knowledge – Output Devices

Monitor

1. Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer.
2. It forms images from tiny dots, known as pixels that make an arrangement in a form of a rectangular form.
3. The sharpness of the image depends upon the number of pixels.

Printers

The printer is an output device, which is to print information on paper.

There are two types of printers:

1. Impact Printers
2. Non-Impact Printers

Plotters

1. A plotter is a printer that interprets commands from a computer to make line drawings on paper with one or more automated pens.
2. Unlike a regular printer, the plotter can draw continuous point-to-point lines directly from vector graphics files or commands.

Memory is of three types

• Cache Memory
• Primary Memory
• Secondary Memory

Cache Memory

Cache memory is a very high-speed semiconductor memory which can speed up CPU. It acts as a buffer between the CPU and main memory.

Primary Memory (Main Memory)

1. Primary memory holds only those data and instructions on which computer is currently working.
2. It has limited capacity and data is lost when power is switched off.
3. It is generally made up of the semiconductor device.
4. The data and instruction require being processed reside in main memory.

There are two sub-categories ROM and RAM in Primary memory.

RAM 

The RAM (random access memory) is the place in a computer where the operating system, application programs, and data in current use are kept.

RAM is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM.

It has two parts:

A. SRAM: Static Random Access Memory

B. DRAM: Dynamic Random Access Memory.

ROM

As the name suggests ROM, stores information that can only be read. Modifying it is impossible or very difficult.

ROM is also a type of non-volatile storage, which means that the information in it stays even if the computer loses power.

This is another type of ROM that is impossible or difficult to change.

• PROM – Programmable Read Only Memory.
• EPROM – Erasable Programmable Read Only Memory.
• EEPROM – Electrically Erasable Programmable Read Only Memory.