COMPUTER APPLICATION SUMMARY

Group Members Rubab shafique Barira Nashal Rimsha Arshad Warda Shadab Hoor-ul-ain

COMPUTER APPLICATIONBit: A computer is an electronic machine. Computer have two states: on and off. Each one or zero is called a bit. It's the smallest unit of information.

Byte (Eight Bits): 8 bits grouped together are called a byte.

American Standard Code for Information Interchange (ASCII) : 128 64 32 16 8 4 2 1

"A" is stored on computer as 0 1 0 0 0 0 0 1 (ASC.65)

"&" is stored on computer as 0 0 1 0 0 1 1 0 (ASC.38)

kilobyte(KB) :Normally defined as 1,000 bytes . Exactly, kilobyte is 1,024 bytes.

A megabyte (MB) :Normally defined as 1,000 kilobytes . Exactly, 1 Megabyte = 1,024 kilobytes

Data: Collection of raw facts or unprocessed information.

Field: Data Item or Unit of Information. ( R.No., Name, Address)

Record: Group of interrelated Fields or information item.

File: One or more records or group of records (Table, Sheet, doc)

Data base: Group of interrelated files.

HISTORY OF COMPUTERS

Abacus; counting.

1st computer like machine Mark I machine. Used mechanical telephone relays

The ENIAC (Electronic Numerical Integrator & Computer) First electronic general-purpose computer, It was Turing-complete, digital, and

capable of being reprogrammed to solve "a large class of numerical problems.

First Generation Machines (Vacuum Tubes):

Computers without moving parts . Based on the flow of electricity . Resistors & vacuum tubes . It Contained over 17,000 tubes.

Second Generation (Transistors):

Transistor made smaller & Cheap computers (1948). Computers shrank in size . Growth of computer industry in the world.

Third Generation (Integrated Circuits)

Integrated circuits, or IC (1970s) . IC - single component containing many transistors . Smaller, cheaper and more reliable

Fourth Generation (microprocessor):

Central processing unit. The Brain of the computer on a single chip .Chip called microprocessor

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COMPUTER: PROGRAMMABLE ELECTRONIC DEVICE THAT CAN STORE, RETRIEVE, AND PROCESS DATA

Accept Information

Hold Information

Process Information

Return Information

Input

Store

Process

Output

HOW COMPUTER HANDLES THE TASK

How computer handle taskInput Devices

Storage Devices

CPU

Output Devices

TYPES OF COMPUTERDigital computer Fast computer

General Purpose

Special Purpose

Analog computer Made of mechanical or electronic parts

Hybrid computer Combination of both

Classification of computerMainframe computer Large , expensive , many terminals etc

Mini computer Less expensive , smaller than mainframe,

Less terminal.

Micro computer Computer at SITT, easy to use, inexpensive.

Super computer Fastest Computer , very expensive , used

for heavy stuff.

CPU consist of three parts CU Control programs

ALU Perform arithmetic operations MU Holds Data and Instruction

RAM Random access memory

Temporary memory

Fastest memory

Volatile

ROM Read only memory

Permanent memory

Non-volatile

TYPES OF ROM PROM Programmable read only memory

non-volatile

EPROM Erasable programmable read only memory

non-volatile

MOTHERBOARD COMPONENTS

The different components of motherboard are as follows:

PCI stands for Peripheral Component Interconnect. PCI slots are used for connecting cards, like modems, extra ports (USB, serial, parallel, etc), sound cards, etc. PCI cards replaced ISA cards some years ago, the previous standard.

ISA stands for "Industry Standard Architecture. used in PCs for adding expansion cards. For example, an ISA slot may be used to add a video card, a network card, or an extra serial port.

AGP stands for "Accelerated Graphics Port." AGP is a type of expansion slot designed specifically for graphics cards.

Expansion slots are used to place additional feature cards.

Power Supply converts 220V (AC) to 5V or 12V (DC).

All the circuits are placed on the motherboard. Interface cards are used to add new features to the computer.

RAM stands for Random Access Memory. It is the temporary memory i.e volatile memory

CPU stands for Central Processing unit. It is the brain of computer.

Hard drive is the permanent storage which is used to store information.

DVD or CD- ROM are used to read information stored on CD.

Floppy Disks store information on floppy.

PORTSThe different ports are as follows:

Serial ports are of 9 or 25 pins which is used to connect mouse or modem. Parallel port are used to connect printer and tape drive. USB ports stands for Universal Serial Bus ports. These ports are used to connect multiple devices. Ethernet port are used to connect a computer to a network. VGA port are used to connect a monitor.

INPUT DEVICESInput devices are used to enter data in the computer. They are of two types

Manual input devices: data is entered manuallyDirect data entry (DDE) devices: data is entered through a source

Keyboard is a board with 100 keys. The keys are arranged in four groups.Mouse is a common pointing device.Trackerball is a replacement to mouse and is used where space is less because it has a ball which move pointerScanner is used to input printed images into computer.Any picture is taken by a webcam.Video camera is used to capture moving images.

DDE devices include bar code reader, OMR, OCR, etc.

MonitorCRT Monitors (cathode ray tube)LCD (liquid-crystal display)

PrintersTwo types: Impact and Non Impact

Output Devices

PlottersEssential for graphical applications like Computer Aided Design (CAD) Provide a better quality graphics output than printers Allow the use of different colours .Application package will translate graphic into plotter instructions

SpeakersSound can be output through speakers or headphones.

HARD DISK Provides quick access to large amounts of data Stores data on rotating disk. Rotation speed varies from 4500 to 15000 rpm.

SECONDARY STORAGE DEVICES

Connection Types:1.PATA : (Parallel Advance Technology Attachment) 2. SATA: (Serial Advance Technology Attachment)3. External HDD:

REMOVEABLE STORAGE DEVICEJaz Drive: LS-120 Drive

Zip Drive USB Drive

CD-ROM

CD-ROM

CD-R

CD-RW

DVD-ROM DRIVEDVD Recordable Formats

DVD-R DVD+RW

DVD-RW DVD-RAM

DVD+R

TAPE DRIVE Tape Drive Applications

• Transfer Data

• Back Up Data

• Archive Data

COMPUTER NETWORKINGA computer network is a group of computer systems and other computing hardware devices that are linked together through communication channels to facilitate communication and resource-sharing among a wide range of users.

NETWORK MODELS

1) Peer-to-peer: A network of computers configured to allow certain files and folders to be shared

with everyone or with selected users. Peer-to-peer networks are quite common in

small offices that do not use a dedicated file server.

• Also called workgroup

• Ideal for small networks (10 users)

2) Server-based: • Resources at central location

• Well Organized

administrator controls access to network resources

• Withhold permission for a user to access files, printers, etc

Local Area Networks (LANs)

Group of computers and network

communication devices interconnected

within a geographically limited area

They transfer data at high speeds

They exist in a limited geographical area

Their technology is generally less expensive

Wide Area Networks (WANs) Located within a state or country, or may be

interconnected around the world Interconnect multiple LANs. More Complicated Expensive Unsafe Unlimited rangeEnterprise WANs: Single organization, Security, e.g. SUPARCO Net

Global WAN: Several organizations, No Security, e.g. Internet

All devices connect to a common, shared cable

Wired in a circle. Each node is connected to its

neighbors

All devices connect to a central hub

BUS TOPOLOGY RING

TOPOLOGY

STAR TOPOLOGY

NETWORK TOPOLOGYNetwork Topology refers to layout of a network, how different nodes in a network are connected to each other and how they communicate.

CABLE MEDIA COAXIAL CABLE Thin net (Bandwidth 10MBps)

Thick net (Bandwidth 10MBps)

TWISTED PAIR CABLE STP (capacity of 500 Mbps)

UTP (bandwidth 10 to 100Mbps)

FIBER OPTIC CABLE Most expensive

Data rates 200,000 Mbps

Network Devices

RepeaterSignals weaken as they travel over long distance

Operates at Data Link layer

similar to bridge

Gateway

Router

Hub

Bridge