computer system and prog

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Lecture notes

Computer systems and Progra

mming

Mechanical Engineering

1st

Semester

By: Adam khan Lecturer computer science Sarhad University of science and IT,

Peshawar.



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How is a computer defined?

What Is a Computer?

Electronic device operating under the co

ntrol of instructions

stored in its own memory

The computerfirst, Accepts data such as raw facts, figures, and symbol

then, Processes data into information (Data that is organized,meaningful, and useful )

finally, Produces and stores results



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The Components of a Computer

What is an input device?

Hardware used

to enter dataand instructions

_____



4


What is an output device?

Hardware that

conveys informationto a user

______



5


What is the system unit?

Box-like case

containingelectronic

components

used to process

data



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What is the magical inside the black box?

C P U

Memorycard

Sound

Card

VideoCard

S t o r a g e U ni t s

Power

Supply



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What are two main components on the motherboard?

Central Processing Unit (CPU)

Also called a processor

Carries out instructions

that tell computer what to do

Memory

Temporary holding place for dataand instructions



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What is storage?

Storage media

Physical material on which data, instr uctions,

and information are stored

Storage mediaStorage media

Physical material on which data, instructions,

and information are stored

Storage device

Records and retrieves items to and froma storage medium

Storage deviceStorage device

Records and retrieves items to and froma storage medium

Holds data, instructions, and information

for future use



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Storage deviceStorage device

What is a floppy disk ?

Thin, circular,

flexible disk enclosed in rigid

plastic shell

A Zip® disk looks

similar but has

much greaterstorage capability

(=170 floppy disk)



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What is a hard disk ?

Provides much

greater storagecapacity than a

floppy disk or

Zip® disk

Housed inside the

system unit



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What is a compact disc?

Flat, round, portable Optical disc

CD-ROM CD-RW

Capacity: 673~768 MB

DVD-ROM

DVD+RW

Capacity:4.7 ~ 17.1 GB



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What is miniature storage

media?

Digital

cameras

Digitalcameras

Handheld

computers

Handheld

computers

Portable, thin

memory cards

used in:

Portable, thin

memory cards

used in:



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Primary Memory

Primary memory refers to internal storage of a computer,

where the programs & data are stored.

Primary storage or primary memory provides temporary(RAM) storage during program execution.

Part of primary storage may also contain permanently

(ROM) stored instructions that tell the computer what to do,when it turned on.

Because primary storage is located inside the computer &

is linked directly to the other components of the CPU,access time to data is very fast.



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Primary Memory (continue…)

RAM: (Random Access Memory): HISTORY:

For many years main memory was one of the most expensivecomputer components to the manufacturer.

Their size has been dramatically reduced, & they have become lessexpensive as the manufacturing materials have changed from vacuum

tubes to magnetic cores & then to transistors & finally to the chips weknow today.

The earliest form of main memory was based on vacuum tubes.

There would have required a shelf of vacuum tubes more than a mile

long for very small memory. As the tubes were not so variable their power requirements were high

they generated heat, they failed frequently, & they were slow.



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The transistors, invented in 1947 were much smaller &more reliable provider of main memory.

smaller power requirements & failed less frequently thanvacuum tubes.

Magnetic cores were smaller still.

In mid 1970’s work had begun on new type of mainmemory technology.

A semiconductor material was used.

The main memory of almost all computers today is basedon this technology,

chips are very small & relatively inexpensive tomanufacturer, & they do not consume as much power as

older forms of main memory.



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Functions of RAM:

It is a part of primary storage

where data & programs instructions are held temporarily

They are referred to as Random Access Memory (RAM) chips

because any of the locations on chip can be randomly selected & used

to directly store & retrieve data & instructions.

RAM depends on a steady supply of electricity to maintain data

storage.

When the power of the computer is shut off, everything stored in

RAM is lost. So RAM is a volatile memory, which is subject to loss when the

power is turned off.



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Different types of software have different types of space in

memory

the instructions of any software which is currently running by computer will be stored temporary in RAM.

After closing of that software the memory (RAM) will be

empty. So it is concluded that more space of RAM faster will be

the computer.



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ROM: ( Read only Memory )

As the name implies the contents of read – only storage

memory (ROM), can only be read data can’t be written into it.

ROM may contain information on how to start the

computer & even the instructions to the entire operatingsystem.

The actual content of ROM are usually set by the computer manufacturer, they are unchangeable & permanent.

Because the contents cannot be altered & they are not lost.When the electric current is turned off, ROM is nonvolatile.



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Characters tics of computer

What makes a computer powerful?

Speed ( ideal for processing large amounts of data )

Accuracy (accuracy of a computer is consistently high)

Versatility (capable of performing any task provided)

Power of remembering (store and recall any amount of

information )



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Characteristics (continue…..)

Storage capability (able to store tremendous amounts of data )

No feelings (can’t make judgments on their own)



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Types of computers (According to work)

Three types:

1) Analog computers:

•Analog data (Temperature, pressure, speed, voltage)

•Continues

•E.g: Speedo meter (car speed)



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Types (continue…)

2) Digital computers:

•1-ON 0-OFF

•Process numeric and non numericdata

•General purpose



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Types (continue……)

3) Hybrid computers:

•Combination of digital and analog

•Speed of analog

•Memory & Accuracy of digital

•Used where both type of data

processed

•E.g:

In hospitals ,ICU: Analog device

measure temperature and B.P ,which

are then converted into digits.



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Classification of Computers

1)Super computers:

Largest, fastest and more

expensive50,000 times faster thanmicrocomputers

60 miles of wiring inside

Largely heat production

AC is used all around

Scientific purposeE.g: Earthatmosphere,airplane,oilcompanies



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Classification (continue…)

2) Main frame computers:

Slower, less powerful and less

expensive

Introduced by IBM

Temperature may be adjusted

Storage in Mb.

Uses : Banks, ATM : different

branches



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3) Mini computers:

General purpose

Smaller and less expensiveStorage as Tape,floppy,and

removable disks

Accounting, scientific and

databases



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Classification (continue…

4) Micro computers :

Smallest, less expensive

Keyboard, disk drives, monitors, printer, cables

Connected capability



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5) Desktop computers:

As micro computer

The mini computer that fits nicelyon the top of a desk at home or

office



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Classification (continue…

6) Laptop:

Briefcase computer

KeyboardLCD



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7) Handheld computers:

A Portable computer that is small enough to

be held in one's hand.

extremely convenient to carry

ipod, iphone, cell phones etc

Provides personal organizer functions

Calendar

Appointment book

Address book

Calculator

Notepad



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Types of computers (according to purpose)

1) General purpose:

Word processing

Databases Controlling security

Can store and execute data



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Types( continue…)

2) Special purpose:

Particular problem

Dedicated computers Games, control of traffic lights, weather prediction

Perform only one task



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Software's

Definition: “Software is made up of programs each of

which is a group of related instructions that perform very

specific task “ “Bridge”, between and a computer system

Software can generally be divided into two categories

System software Application software



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Types of software's

Software’s

System Software's Applications Software's

General Purpose s/w Special Purpose s/w



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Computer Software

What is system software?

Operating System (OS)

is a set of programsthat coordinates all

activities among

computer hardware

devices and allows

users to runapplication software

Operating System (OS)Operating System (OS)is a set of programs

that coordinates all

activities among

computer hardware

devices and allows

users to runapplication software

Utility Programs allow the user to perform maintenance-type tasks

usually related to managing a

computer, its devices or its programs

Utility ProgramsUtility Programs allow the user to perform maintenance-type tasks

usually related to managing a

computer, its devices or its programs

Programs that control the operations of the computer and

its devices



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Computer Software

What is application software?

Presentation

Graphics

Spreadsheet

Database

Word

Processing

Programs that perform specific tasks for users

Suite

Popular software applications bundled

together as a single unit

Application software categorizes in two groups.General purpose software.

Special purpose software.



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Types of Application Software's

General Purpose S/w:

Enough features to do a wide variety of tasks (jobs)

like Microsoft word which is a package includes word,excel, power point, & access

it can be used by a student to write a research paper

by an office secretary for mailing lists.etc

The student, the secretary, or the lawyer can use the same

software.

'



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Special Purpose Software's

Special purpose software performs a ver y specific task for a

user.

cannot be changed to perform specific task for specific user.

H d '



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Hardware's

“The computer and its associated equipments are called as Hardware devices”

Physically exist

We can touch

Can be replaced

There are four important areas in computer, which comes inHARDWARE

1) Input devices

2) Output devices

3) CPU

4) Secondary storage devices

H d ( i )



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Hardware (continue … )

Output devices: “to view information”

a) Printers

b) Monitorsc) Plotters

d) speaker

H d ( i )



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Hardware (continue …)

Processing Hardware(CPU): “ Interpret and direct the

execution of software's”

a) CPU b) Main Memory

H d ( ti )



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Hardware (continue…)

Storage devices: “ To store computer instr uctions and data in

a form that is relatively permanent.”

a) Hard drives b) Flash Memory

c) CD/DVD disks

H rd r d i ( ntin )



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Hardware devices (continue…)

1) Input devices: “To collect data and convert it into a

computer readable form.”

a) Key boardb) Mouse

c) Touch pad

d) Scanner

e) Touch screen

Operating system:



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Operating system:

“An operating system is a set of programs that allows the

computer to control and manage its own resources, such

as the central processing unit, memory and secondary

storage”.

intermediary between the hardware and software programs

(Application) such as word processing and data base

programs.

Much of work of an operating system is hidden from the

users; many necessary tasks are performed behind the

scene.

Operating System (continue )



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Operating System (continue…)

Evolution:

In early days The programmer first writes a pr ogram & operates the program directly from the operator console.

As time went on, additional, software & hardware were developed. First operating was developed in 1950’s which was only used by IBM

701, computer system.

After as the time was passed much operating system software wereintroduced, like windows, Apple Macintosh

Microsoft Macintosh

Dos (disk operating system) Apple (operating system)

(Text based) G U I Windows version

G U I (graphical user interface)




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Microsoft operating systems:

(1) DOS: (Disk operating system):

This operating system was used for earlier Intel’s personalcomputers.

It was early developed in 1981 for IBM personal computer.

Its interface is command line because it is text baseenvironment.

It supports only one user at a time & single processor.




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(2) Micro Soft windows:

(a) MS win 3.x:

This version enables the user to take full advantage of Intel’s processor 80386.

Other versions win 3.1, 3.11,

(b) Win 95 & win 98: It was true operating system, & key feature was

multitasking.

Its properties was internet connectivity, update driver including DVD-ROM discs & devices for USB

(Universal serial bus) connection



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(C) MS win Me ( millennium):

This operating system was released in 2000; it improved

capability of multimedia & digital video editing support.(d) Ms win CE ( consumer electronics):

This OS is designed for personal digital assistant (PDA),

and it is the light version of windows which used for mobiles, e.t.c




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(e) MS win NT ( network )

This OS designed for networking (client/ server)

(f) MS win 2000:

This OS was released in the year 2000.

It combines user friendly interface & features of win 98 withfile system, networking power & stability, and newimprovement was done.

It has four editions.

MS win professional MS win server standard edition

MS win advanced server MS win data center server




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(g) Windows XP

Microsoft has developed Windows XP is a line of operating

systems for applying on general functional computer systems which includes business and home desktops, media

centers and notebook computers.

Windows XP was released on 25th October 2001.

(h) Windows XP 64-bit Edition 2003

(i) Windows Server 2003

(j) Windows XP Professional x64 Edition




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(k) Windows Vista After a world-wide success of XP and its service packs Microsoft has

designed and created Windows Vista the operating system for use on

personal computers, including business and home desktops, Tablet PCs,

laptops and media centers.

It was first named as "Longhorn" but later on 22nd July 2005, the name was

announced as Windows Vista.

The development of Vista was finished on 8th November, 2006. In the next

three months Vista was available in steps to computer software and

hardware manufacturers, retail counters, and business organizations.

It was released globally on 30th January 2007, for the general public.

(l) Windows Home Server (m) Windows Server 2008

(n) Windows 7

Programming



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Programming

“A program is a set of step by step instructions that direct thecomputer to do the task user wants”.

Programming process:

Define the problem:Problem can be analyzed by the user’s wants & needs.

Planning the solution:

After the analysis a software engineer’s think that how to plane the

solution for the user needs.Coding:

Coding is done by different programming tools.

Testing:

After the coding the s/w which is build, should be tested.

Documenting:

The detailed description & the programming cycle.

Programming (continue…)



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g g ( )

Programming languages:

consists of all the symbols, characters.

There are several thousand programming languages,

programming languages consists of a vocabulary & set rules(called syntax ), that the programmer must learn.

Instruction of programming languages:

Input & output instructions ( data c.p.u )

Arithmetic instructions ------ mathematical operation

Logical instructions --------- comparison

Control instructions ---------- execution

Data movement instructions------- copy & move

Specification instructions--------- to specify memory allocation.




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g g ( )

Levels of Programming Languages:

Basically, programming languages are divided into different

levels.1) Low level languages

2) High level languages.




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g g ( )

Levels of Programming Languages:

Levels

Of

Prog: Languages

Low Level Languages High Level Languages

Machine Level Languages

Assembly Level Languages

V.High Level Languages

Natural Languages




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g g ( )

Low level languages:

Low level computer programming languages are machine

codes or close to it. Computer can’t understand instructions given in high level

languages or in English.

It can only understand & execute instructions given in theform of machine language, i.e. the language of 0, 1. There

are two types of low level language.

1. Machine Languages2. Assembly languages




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g g ( )

1)Machine language: ( first generation lan guage)

(Instruction that computer execute directly).

It is the lowest & most elementary level of programminglanguage & was the first type of programming languagewhich to be developed.

Computer can only understand machine language.

The computer manufacturer when design a computer so itwill be necessary to obey just one language,

i.e. machine code. 0, 1, where 0, stands for OFF & 1,

stands for ON, of electric pulse.




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Advantages:

It makes fast and efficient use of the com puter.

It requires no translator to translate the code i.e. directlyunderstood by the computer.

Disadvantages:

All operation codes have to remember. All memory addresses have to be remembered.

To find out the error, is difficult.

These are machine dependent.




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Assembly language: (second generation language)

designed to overcome the difficulties of machine language.

The operation codes & operands are given in the form of alphanumeric symbols instead of 0’s & 1’s.

These codes were called “mnemonic codes”, e.g. ADD for addition, SUB for subtraction, e.t.c.

there was very small English support language given to thislanguage.

The instructions of the Assembly language will also be

converted to machine codes by language translator to beexecuted by the computer. E.g. ADD CX AX.




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Advantages:

It is easy to use & understands as compared to machine

language. Its error may be located easily.

The modification is easy.

Disadvantages: It is also machine dependent

It was machine dependent so the programmer should have

the knowledge of the hardware.




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High level languages: (third generation language)

This type of computer language is very much like everydaytext & mathematical formulas.

It’s designed is to run on different computers with few or no change. It means the compatibility.

Its format close to English language these are basically

symbolic languages rather than mnemonic codes”. This type of languages depends on.

Type of the problem.

Purpose :business, educational e.t.c

Ease of learning & use.

Portability

Documentation provided.




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Advantages:

User friendly.

Similar to English vocabulary.

Less time required to write.

Easier to maintain.

It is problem oriented.

It is compatible.

Portable.

Disadvantages:

It should be translated for the convert in machine language, so thecomputer time is waste.




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Very high level languages: (fourth generat ion )

In this type of languages, programs are developed;

speed is much higher and also required minimum user effort.

The level of programming skills not required much more.

Its maintenance is less because it reduces error.

When we want to change the program so it is easy.

These languages usually used in conjunction with data base.i. Query languages

ii. Report generators

iii. Application generators

iv. Decision support system & financial planning language(information & data)

v. Micro computer application s/w (create s/w for specification)




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Natural languages:

The natural languages statements are very closely resemble

to human speech. These types of languages used in expert system, artificial

intelligence e.t.c.



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Assembler:

Translate assembly code to machine language supplied by

the manufacturer of computer.Complier:

Program written in high level language to convert in

machine instructions, before running the program, i.e.whole program.

Interpreter:

Program written in high level language to convert inmachine instruction, before running the program , i.e. each

& one statement of the code.

Data Communication and Networks



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Data Representation

Different forms of data Representation

Text: bit pattern i.e 0,1 Numbers: Bit pattern i.e 0,1

Images: Bit Pattern but mechanism is different , Image

is divide into pixels, called as resolution. Audio: converted into signals

Video: combination and image and video.

Direction of Data flow



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Communication b/w two devices can be of three types

Simplex : data is unidirectional, one device transmits and

the other receive, e.g. keyboard

Direction of Dataflow



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Half duplex: each device can transmit and receive data/message but

not at the same time, it is like one lane road. E.g walkie talkies, radios,

etc



Data communication



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Sharing of information

“exchange of data b/w two devices via some form oftransmission medium”.

Fundamentals characteristics of data communication:

Delivery: correct destination, sender or receiver Accuracy: in time of transmission data must secured

Timeliness: Timely manner

Components of data communication

Protocol



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1)Message

2)Sender

3)Receiver

4)Medium

5)Protocol

Message

Step#1

Step# 2

Step# 3

....

ProtocolProtocol

Step#1

Step# 2

Step# 3..

..

Sender Receiver

Medium

Message

Sender

Types of Networks



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There are three types of Networks:

1) LAN (Local Area Network)

2) MAN( Metropolitan Area Network)3) WAN (Wide Area Network)

Local Area Network



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Privately owned

Within single office, building or campus

May be as simple as two PC’s and a printer

Limited to few Kilometers

Limited users

Metropolitan Area Network



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Designed to extend over an entire city

May be a single network

It may be a means of connecting a number of LAN’s

A company can use a MAN to connect the LAN’s in all

its offices through a city

MAN may be wholly owned and operated by a privatecompany

E.g: cable TV network

Wide Area Network



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Provides long distance of transmission of data, voice,

image, video over large geographic areas

May be country to country, continent to continent

Unlimited number of users

Internet is best example of WAN

Networks and the Internet



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One type isa modem

What is a network ?

Enables a

connection

between

computers

Enables a

connection

between

computers

Cables

Cellular

radio

Telephone

lines

Satellites

Communications

Media

Communications

Media

Communications

Device

Communications

Device

Collection of computers and devices connected together




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To shareTo share

Why do we need network?

ResourcesResources

Hardware

devices

Hardware

devices Software

programs

Software programs

DataDataTo save

time

andmoney

To save

time

and

moneyInformationInformation

Internet



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Also called “internetworking”

Technically it is best defined technology for linking

LAN’s into a huge congested networks.

ISP( who sell internet subscription to the public

Interoperability

Global Network of computers More interactive than the other types of media

Internet



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Worldwide collection of networks that connects

millions of computers

Internet (History)



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The internet began way back in 1961, but it was called the“ARPANET” (Advanced Research project Agency), within the USdefense Department, in conjunction with a number of universities &military contractors.

Its purpose was to explore the possibility of a communication. Network that could survive a nuclear attack.

The “ARPANET” quickly developed into a communication tool.

It was used for e-mail, discussion groups & for exchanging files. In 1979 its capacity of users increased & popular & more universities

connected.

Some other communication networks were introduced, but these were

not go along with internet because they have very complications & problems in communication with other computers.

Internet (History)



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In 1983 a standard communication protocol was introducecalled as “TCP/IP” (transmission control protocol / internet

protocol).

So the internet became very sophisticated & increasinglygrowth of internet starts of its multi advantages.

Protocols: In data communication & networking, a standard

specifying the format of data & the rules to be followed iscalled “Protocol”.

The function of a network are the standards, these are

“Protocols”.

Internet (uses)



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(1) To find general information about a subject:

The web is like a huge encyclopedia of information.

The information find on the internet is amazing, It offers much different perspective on one single topic

Also we can access that information which is not easily

accessible, e.g. online apply to international universitiesreading books, much more information.

Internet Uses (Continue…)



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(2) To meet people:

The web is generally a very friendly place.

People may use e-mail which is cheap & very easy, also itis very faster.

Different types of chatting software's have been developed

for this purpose. It offers text chat as well as voice chatting also.

Internet Uses (continue…)



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(3) To learn:

On-line distance education courses can give you an

opportunity to gain a qualification over the internet.

(4) To find software’s:

The internet contains a wealth of useful downloadablesoftware’s.

Some are for limited time & some are full versions of

software.




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(5) To buy things:

If you want to buy something through internet, so there are

many companies who offering his services.

But “Security “for online shopping is still not good, as well

as some websites may have minimal security.

(6) To advertise a product:

Most company websites start up as a big advertisement for

their products & services. Companies may also give away some information for free

as an incentive for people to visit their pages.


(7) T ll d



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(7) To sell a product:

Internet shopping (E- commerce) is still is its growth ittakes a very good marketing strategy to actually make

money out of selling items over the web.(8) To make money:

A popular way to make money out of the web is from

advertising revenue. Popular websites have banners at the top of the page attract

people to click them and be taken to the advertiser’s

website. These banners are generally animated and veryappealing, with good messages, to make users wonder.


(9)T h k l d i h h ld



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(9)To share knowledge with the world:

Many individuals write webpage’s to share information

about their interest or hobbies.

They just feel that the web has given then so much

information that at least they can put something that can be

useful for others.



Internet (Features)

3) I t t li ht d



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3) Internet near light speed:

Digital information such as internet packets travel at 2/3of the speed of light on copper wire and on fiber optic

cables

Light speed is 300,000 km/sec

Internet (Features)

4) Universal internet access:



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4) Universal internet access:

Gives same powerful capabilities to everyone who has

connected and accessing the internet

Internet (Features)

5) Internet Growth rate:



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5) Internet Growth rate:

Depends upon three directions

a) size:

more than half the world’s population now using internet

b) Power:

more powerful software's have been developed

c) Functionality:

new software's and new browser’s



Internet (Features)

7) Internet freedom of speech:



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7) Internet freedom of speech:

Common area, Public place like village.

Any thing that any body wishes to say can be heard by

anyone else connected to internet.

Web Browser

A web Browser display a web documen

t and enables users



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A web Browser display a web document and enables users

to access linked documents

When the user chooses a hyperlink, the browser originates a

message to a web server

Browser also contains navigation tools

The first web browsers were “Text -only browsers”

first successful graphical browser, mosaic

Developed by the “National center for supercomputing

Application” (NCSA)

Web server

A web server is a program that waits for

browsers to request



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A web server is a program that waits for browsers to request

a web page.

When the server receives request for a specific resource, it

looks for the requested file & sends it to the browser


What is the World Wide Web (WWW)?



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What is the World Wide Web (WWW)?

A Web site is

a collection of

related Web pages

A Web site is

a collection of

related Web pages

A Web page contains

text, graphics, sound,

video, and links to

other Web pages

A Web page containstext, graphics, sound,

video, and links to

other Web pages

You can share

information by

creating Web pagesor posting photos on

a photo community

You can share

information by

creating Web pages

or posting photos on

a photo community

Billions of documents, called Web pages, available to

anyone connected to the Internet



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Prepared by: Adam Khan

computer system and prog

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