IT101 lecture1 and 2
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Transcript of IT101 lecture1 and 2
Week 1Lecture #1, 2
Introduction to computer
SystemA set of detailed methods, procedures, and
routines established or formulated to carry out a specific activity, perform a duty, or solve a problem.
Sub-systemA major part of a system which itself has
the characteristics of a system, usually consisting of several components.
Computer SystemA complete, working computer along with
softwares and peripheral devices that are necessary to make the computer function is called Computer system. Every computer system requires an operating system to operate.
Computer System
Lets enter in the world of computers…..!!!!
Computer Literacy (Digital Literacy)
Why we use Computers ?
Why we need It ?
Computers are present in every aspect of daily living –in the workplace, at home, in the classroom, and for
entertainment
An electronic machine that can accept data (input), manipulate the data according to specified rules (process), produce results (output), and stores the results for future use.
What is a Computer?
What is a Computer?An electronic device designed to accept
data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.
Data VS Information
Data Collection of raw facts and figures.Information processed form of data which is
meaningful.
Information processing cycleSeries of input, processes, output and
storage.
A computer often holds data, instructions and information for future use.
The Components of a Computer
Input devicesOutput devices System unitStorage devicesCommunications devices
The Components of a Computer
AdvantagesIt helps you automate various tasks that you
can/cannot do manually.It helps you organize and store your bulky
data and information in a better way. It has much more computing and calculating
power than an ordinary human. It may help your work to be a lot easier. It may be the storage of your important data
and files.
AdvantagesIt may be your handy book. It may help you solve problems faster than
an ordinary human being can do. It has speed, storage, reliability,
consistency and communications.It helps you to find useful information using
the Internet. It helps in businesses, factories, offices,
schools and homes.
Disadvantage It destroys your social life and interactions
with humans if you do not maintain the balance.
It may effect to the destruction of your eye sight due to radiation.
It may damage your studies and life.
Disadvantage The way it distracts and can deviate our
thoughts and activities towards un-productive activities.
It could cause violation of privacy, impact on labor force, health risks, impact on environment, distraction from work, and antisocial influences.
Types of Computer Computer types can be divided into 3 categories
according to electronic nature.Analog Computer Digital Computer Hybrid Computer
Analogue ComputerAnalogue types of Computer uses analogue
signals that are represented by a continuous set of varying voltages and are used in scientific research centers.
Analogue Signal and Analogue Devices
Digital Computer A computer that stores data in terms of digits
(numbers) and proceeds in discrete steps from one state to the next. The states of a digital computer typically involves binary digits which may take the form of the presence or absence of magnetic markers in a storage medium. In digital computers, even letters, words and whole texts are represented digitally.
0,1False trueLow high
Digital Signal and Digital Devices
Hybrid ComputersDesigned to display the features and
characteristics of both analog and the digital computers.
When the hybrid computers are used in the form of digital computers then they are deigned to act as the controller for the operations carried out in the system.
When analog is taken into account then in that case the computer acts as a solution provider for different problems that exit.
By depicting both the feature, it is found to be a beneficial computer.
Examples of Hybrid Computer
Classification of Computer
There are two types of classesClasses by size Classes by Functions
Classes by size
Microcomputers (Personal computers)Minicomputers (Midrange computers)Mainframe computersSupercomputer
Classes by functions ServersWorkstationsInformation appliancesEmbedded computers
Microcomputers Microcomputers are the most common type of
computers used by people today, whether in a workplace, at school or on the desk at home. e.g.
Desktop computers Game consoles LaptopsNotebook computersPalmtop computersTablet PC Programmable calculator
Palmtop Computers
Tablet PC
Notebook Computers
Programmable calculators
Game Console Laptops
MinicomputersContemporary term for this class of system
is midrange computer.Lies in the middle range of the computing
variety in between the smallest multi-user systems (mainframe computers) and the largest single-user systems (microcomputers or personal computers), Power between mainframe and desktops.
Class of multi-user computers handled by hundred of users.
MinicomputersUsed in smaller organizations.Initially these had category between
mainframe and personal computers.Now a days we use server machine instead
of mini computers.such as the higher-end SPARC, POWER and
Itanium -based systems from Sun Microsystems, IBM and Hewlett-Packard.
Mini computers
Mainframe computersUsed in large organizations.A very large and expensive computer
capable of supporting hundreds, or even thousands, of users simultaneously.
Also called enterprise servers.There are multiple processors in these
computers(2,4,12).Banks and shopping marts are
interconnected through mainframe computers.
Main frame computers
Super Computers All of the resources to tackle one problem Used for very complex operations 1. Rocket launching 2. Assembling 3. Weather prediction 4. Aeronautics 5. Testing of nuclear weapons Cray one 160 millions instructions /second 160 trillion bytes storage 6 trillion bytes memory
Super Computers
Comparison between Minicomputer, Mainframe & SupercomputerIn some ways, mainframes are more
powerful than supercomputers as they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.
The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.
Hierarchy of Computers In the hierarchy starting with a simple
microprocessor (watches) at the bottom supercomputers at
the top, mainframes are just below super
computers.
Comparison TableCategory of computer
Number of simultaneous users
Size of computer
Personal computer(desktop)
Fits on a desk Usually one(more if networkerd)
Mobile computer and Mobile devices
Fits on your lap or in hand
Usually one
Game console Small box or hand held device
One to several
Server Small cabinet Two to thousands
Mainframe Partial room to full room of equipment
Hundred to thousands
Super computer Full room of equipment
Hundred to thousands
Embedded computer
Miniature Usuaally one
Servers
Server is a physical computer (a hardware system) dedicated to running one or more such services (as a host) to serve the needs of users of the other computers on the network.
Types of ServerDepending on the computing service that it
offers it could be1.Database server2.File server3.Mail server4.Print server 5.Web server
Database ServerProvides database services to other computers
as defined by the client-server model.DBMS provide database server functionality, In a master-slave model, database master
servers are central and primary locations of data while database slave servers are synchronized backups of the master acting as proxies.
e.g.Oracle, DB2, SQL server
File Server Computer attached to a network with
primary purpose of providing a location for shared disk access,
i.e. shared storage of computer files (such as documents, sound files, photographs, movies, images, databases, etc.) that can be accessed by the workstations that are attached to the computer network
Mail ServerEvery email that is sent passes through a
series of mail serversA complex series of transfers takes place. Without this series of mail servers, email
can be sent to the email address of the same domain.
Server
Client Server Network
Workstations
In networking, workstation refers to any computer connected to a local-area network. It could be a workstation or a personal computer.
Information applianceIn information appliance or information
device is any machine or device that is usable for the purposes of computing, telecommunicating, reproducing, and presenting encoded information in innumerable forms and applications.
Information appliances
Embedded Computers Embedded computers can be compared to
"computers on a chip". All in one , so to speak. You will find them in all kind of devices surrounding us where you need to regulate something, control or check something
e.g. Home automation devices e.g. Washing
machines, Sewing machines, Microwave Ticket machines at the subway, Cameras, clocks Cell phone, Video games, Global
Positioning System Automobiles, cars, motors (antilock brakes)
Mobile DevicesHandheld ComputersPDASmart PhonesGPS
Hand Held Computers
Personal Digital Assistant (PDA)
Smart phones
Global Positioning System