itis- components of it

7/30/2019 ITIS- Components of IT

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Components OfInformation Technology

Dr. Gita A. KumtaSchool of Business Management

NMIMS (Deemed University)


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What is a Computer?

An electronic device that stores, retrieves,

and processes data, and can be programmed with

instructions.

A computer is composed of hardware and

software,

Can exist in a variety of sizes and configurations.


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Types of Computers

Mini and Mainframe Computers

Very powerful, used by large organisations such as

banks to control the entire business operation.

Personal Computers

Cheap and easy to use. Often used as stand-alone

computers or in a network. May be connected to largemainframe computers within big companies.


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Packaging the Computer

The many physical forms of the

general purpose computer

All follow general organization:

Primary memory

Input units

Output units

Central Processing Unit

Super Computers

Mainframe Computers

Minicomputers

Microcomputer

Palmtop Computer

Calculator

Fast Expensive Complex Large

Slow Cheap Simple Small


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Basic Concepts of Computer

Hardware The term hardware refers to the physical components of your

computer such as the system unit, mouse, keyboard, monitor etc.

Input / Output (I/O): Refers to the process of getting

information into and out of the computer.

Input: Those parts of the computer receiving information to

programs.

Output: Those parts of the computer that provide results of

computation to the person using the computer.


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Computer System

Cont.


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The Central Processing Unit

The Central Processing Unit ( CPU)

Often referred to as the brain of the

computer.

Responsible for controlling all activities of thecomputer system.

Motherboard: The place where most of

the electronics including the CPU aremounted.


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Major Components of CPU

The three major components of the CPU are:

Arithmetic Unit (Computations performed)

Accumulator (Results of computations kept here)

Control Unit (Has two locations where numbers

are kept)

Instruction Register (Instruction placed here for

analysis) Program Counter (Which instruction will be performed

next?)

Instruction Decoding Unit (Decodes the instruction)


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Input Devices

Connecting Hardware to the computer

Hardware needs access through some general

input/output connection.

Port: The pathway for data to go into and out of the

computer from external devices such as keyboards.

There are many standard ports as well as custom

electronic ports designed for special purposes.

Ports follow standards that define their use. SCSI, USB: Multiple peripheral devices (chain).

RS-232, IDE: Individual peripheral devices.


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Input Devices

How to tell it what to do and capture input?

Two categories of input hardware:Those that deal with original data.

Those that handle previously stored data.


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Input Devices

Input hardware: Those that deal with originaldata.

Keyboard

MouseVoice recognition hardware

Scanner

Digital camera

Digitizing: The process of taking a visual

image, or audio recording and converting it to a

binary form for the computer.


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Input / Output DevicesCategory Name of the Device

Keying Device Keyboard

Punch Card Reader

Pointing Device Mouse

Touch Screen

Joy Stick

Light Pen

Optical Character Recognizer Bar Code Reader

Optical Character Reader

Other Devices Cameras

Digitizers ( for maps a, graphs etc )

Smart Cards

Telephone

Output Devices Printer, Plotter, Fax, Monitor


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Input Devices

Peripheral device: A piece of hardware

like a printer or disk drive, that is outside

the main computer Hardware needs software on the computer

that can service the device.


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Input Devices

Basic Technologies for Storing

Common Basic Technologies for Storing

Binary Information:

Electronic

Magnetic

Optical


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Input Devices

Electronic Circuits Most expensive of the three forms for

storing binary information.

A flip-flop circuit has either one electronic

status or the other. It is said to flip-flop from

one to the other.

Electronic circuits come in two forms:

Permanent

Non-permanent


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Input Devices

Optical

Uses lasers to read the binary information

from the medium, usually a disc. Millions of tiny holes are burned into the surface of

the disc.

The holes are interpreted as 1s. The absence of holes are

interpreted as 0s.


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Secondary Memory Input Devices

These input devices are used by a computer to storeinformation and then to retrieve that information as

needed.

External to the computer.

Commonly consists of floppy disks, hard disk drives, or

CD-ROMs.

Secondary memory uses binary.

The usual measurement is the byte. A byte consists of 8 binary digits (bits). The byte is a

standard unit.


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Storage Devices

How it saves data and programs for retrieval? The four most important characteristics of

storage devices:

Speed and access timeCost / Removable versus non-removable

Capacity

Type of access


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Storage Devices

Speed (Access time) - How fast information

can be taken from or stored onto the

computer memory devices medium.

Electronic circuits: Fastest to access.

40 billionths of a second.

Floppy disks: Very slow in comparison.

Takes up to 1/2 second to reach full speed beforeaccess is even possible.


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Storage Devices

Type of Access

Sequential - Obtained by proceeding

through the storage medium from the

beginning until the designated area isreached (as in magnetic tape).

Random Access - Direct access (as in

floppy and hard disks).


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Output Devices

How it shows you what it is doing / done?

Monitor

The monitor (the screen) is how the computer sendsinformation back to you.

Printer

A printer is also an output device. There are many differenttypes of printers. In large organizations laser printers are used

as they can print very fast and give a very high quality output.


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Output Devices

Storage Requirements: How much storage

capacity is needed for One keystroke on a keyboard. 1 byte (8 bits)

One page single-spaced document. 4.0 K

Storage Capacity: How much data can be

stored on One inch of 1/2 in. wide magnetic tape. 4 K

One DVD. up to 17 GB


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Output Devices

Plotters

A plotter is an output device similar to a printer,

but normally allows you to print larger images.

SpeakersEnhances the value of educational and presentation

products.

Speech synthesisersGives you the ability not only to display text on a

monitor but also to read the text to you.


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Software

The software is a set of programmes, datastructures and documentation.

Programmes are a set of instructions that

makes the computer work with data.

Software is held either on your computers hard

disk or a storage device and copied into the

RAM (Random Access Memory) as and whenrequired.


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Types of Software

System Software

Application Software

Business Application Software


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System Software

Controls various internal computer

activities.

Covers the following categories:

Operating system,Utility software

Data Base Management System.

Device driver that will allow thecomputer to communicate with a

particular device.


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Used to perform specialized functions or

specific jobs.

Specific jobs might be to create a family tree,

learn basic math, create a plot for a novel, do

payroll and accounting, collect payment, or

draw flowcharts.

Users can choose from thousands of

applications to facilitate the job.


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Cont.

Type Software

Word Processing Microsoft WordCorel Word Perfect

Spreadsheet Microsoft Excel , Open Office /

Star Office

Graphics Adobe Macromedia

Desktop Publishing Corel

Major Categories of



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Business Application Software

Software that enables Business functions.

From a batch process to on-line, real-time.

Billing system, inventory system, accounting.

Enterprise Resource Planning System

Data Warehousing

Business Intelligence


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Programming Languages

Various methods of writing computer

instructions.

Instructions adhere to a particular set ofprotocols for each language.

Regardless of which language a program

was written in, a computer can only

process binary code.


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Generations of Computer Languages

First generation of computer languages wasmachine language.

Second generation is assembly language

developed in the 1950s.

Third generation (3GL) languages, called

high-level languages.

Fourth generation (4GL) languages, called

very high-level languages which rely onobjects of code that are reusable.


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Information:

Refers to data that is viewed in some context. May involve some processing also, e.g., a list of month-

wise sales with the total yearly sales calculated. Information helps the user reveal trends or patterns in the

data.

Database:

It is a shared and organized collection of logically relevantdata designed to meet the information needs of multiple users

in an organization, e.g., a database of all the addresses.

Database Concepts


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Data Versus Information

Monthly Sales Report

for West Region

Sales Rep: Charles Mann

Emp No. 79154Item Qty Sold PriceTM Shoes 1200 $100


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Logical Data Elements

NameField

PayrollRecord

PayrollFile/Table

PersonnelDatabase


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Views of Data

There are different ways in which we can

view the data.

A database system typically has two levelsof abstraction of data:Physical level: Describes how a record (e.g., a

customer) is physically stored on the computer

Logical level: Describes data stored in thedatabase and the relationships among them,


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Data Modeling

Analysis of data objects that are used in a

business or other context and the identification

of the relationships among these data objects.

Is a collection of logical constructs used to

represent the data structure & the data

relationships found within the database.


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Categories of Data Models

Conceptual models Focus on the logical nature of the data representation.

Concerned with what is represented rather than how it is

represented.

Entity-Relationship Diagram (ERD) is a popular conceptualmodel.

Implementation models Place the emphasis on how the data are represented in the

database : Hierarchical, Network, Relational, Object-oriented.


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Hierarchical Model

In 1966, IBM released the first commercially availableDBMSIMS (Information Management System) based on

the hierarchical data model. The basic structure of this

model is:

Collection of records is logically organized to conform to

the upside-down tree (hierarchical) structure. The top layer is perceived as the parent of the segment

directly beneath it.

The segments below other segments are the children of the

segment above them. A tree structure is represented as a hierarchical path on the

computer's storage media.


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Network Model

General Electric (GE) developed a DBMS calledIDS (Integrated Data System) based on the

network data model in 1967.

In this model, a relationship is called a set.

Each set is composed of at least two record types:

an owner (parent) record and a member (child)

record.

A set represents a 1:M relationship between the

owner and the member.


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Network DBMS


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DBMS between the Database and the End Users


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Data Dictionary Management

A data dictionary (or metadata) is the collection ofdescriptions of the data objects or items in a data

model for the benefit of the programmers and others

who need to refer to them.

Data storage management Data transformation and presentation

Security management

Multi-user access control

Backup and recovery management

Data integrity management Database access languages and application programming interfaces

Database communication interfaces.


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Sources of Data for the Computer

Two types of data stored within a computer: Original data orinformation: Data being introduced to a

computing system for the first time.

Computers can deal directly with printed text, pictures,

sound, and other common types of information.

Previously stored data orinformation: Data that has already

been processed by a computer and is being stored for later use.

These are forms of binary data useful only to the computer.

Examples: Floppy disks, DVD disks, and music CDs.


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Moving Information

Within the Computer How do binary numerals move into, out of,

and within the computer?

Information is moved about in bytes, ormultiple bytes called words.

Words are the fundamental units of information.

The number of bits per word may vary per

computer.

A word length for most large IBM computers is 32

bits:


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A network provides the following major

benefits:

Simultaneous (or concurrent) access tocritical program and data

Sharing of peripheral devices (e.g.,

printers) Streamlined personal communications

Easier back-up processes.

Networking Concepts


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Any network can be studied in either of the following ways:

LAN

WAN

MAN

Geography

Bus

Star

Ring

Mesh

Server-based

Client/server

Peer-to-peer

Interactions

Network Design

Topology


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Types Of Networks

LANLocal Area Network

Is a small Geographical area such as Institute.

MANMetropolitan Area Network

Is a network over a larger geographical area such as the

provincial government.

WANWide Area Network

Is a network used over an extremely large geographicalarea such as the federal government.


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Bus Topology

Allows information to be directed from one computer to the other.


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Is the most common type used.

All computers are attached to a hub.

Less collisions and most efficient.

Star Topology


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Uses a token to pass information from one computer to

the other.

A token is attached to the message by the sender to

identify which computer should receive the message. As the message moves around the ring, each computer

examines the token. If the computer identifies the token

as its own, then it will process the information.

If one computer is broken or down, the message cannotbe passed to the other computers.

Ring Topology


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Ring Topology


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Mesh Topology

A network setup where each of the computers andnetwork devices are interconnected with one

another

Allows most transmissions to be distributed, even

if one of the connections go down.

Not commonly used for most computer networks

as it is difficult and expensive to have redundant

connection to every computer. Commonly used for wireless networks.


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Mesh Topology


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Syntax

Structure or format of the data

Indicates how to read the bits - field delineation

Semantics

Interprets the meaning of the bits

Knows which fields define what action

Timing

When and what data should be sent. Speed at which data should be sent or speed at

which it is being received.

Elements of a Protocol

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