By: Mr. Birbal Jat PGT-Computer Sc.

Kendriya Vidyalaya No 3 Jaipur

Computer Fundamentals

Chapter-1

COMPUTER MEANSC : CommonlyO : OperatorM : MachineP: ParticularU: UserT : TradeE : EducationR: Research

The First in Computer World World’s first electronic digital computer- ENIAC. India’s first built digital computer-SIDHARTH Made by ECI. India’s first built super computer-PARAM Made by C-DAC. First computer was established in main post office of Bangalore on 16 Aug 1986. First computerized Post office – New Delhi. PRADESH is computer language for Hindi Commands. In 1971 census – IBM1401 computer was used in India. Dr. Raj Reddy is the first Indian who get Ph.Ed. in computer Science. SYSTMAIL is email service for Indian languages, provided by C-DAC. MONTRA ONLINE- India’s first international internet service. SIKKIM is the first state where telephone directly is available on internet.

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COMPUTER- AN INTRODUCTION Computer is an electronic machine which calculates data very fast and

provides results accurately. It is considered that when we provide accurate inputs in the computer, it provides 100% accurate outputs.

COMPUTER SYSTEM: It is set of hardware and software devices which are connected to each other to solve a specific problem.

DEVICES: Monitor, keyboard, Mouse, Printer etc. COMPUTER HARDWARE is a set of physical and magnetic devices which are

used to make computers. We can see and touch these peripherals.

Example: The outside border of a computer system.

COMPUTER SOFTWARE is a set of programs which are written in computer languages i.e. machine, binary. These are used to work on computer system. These provide instructions to various parts of a computer system.

Example: Windows 98. COMPUTER FIRMWARE is a combinatin of S/w & H/w. Computer Chips that have data

recorded on them. Example: iPod, Bluetooth, iBook LIVEWAREi : is the term used for the people associated with and benefited from the computer

system. Example: getting feedback from users.

Characteristics of Computers

Advantages: Speed: Computers are much faster as compared to human beings. A computer

can perform a task in a minute that may take days if performed manually.

Accuracy : Computers can perform all the calculations and comparisons accurately.

High Storage: Computers can store a large amount of information in very

small space. Reliability: Computers are immune (unaffected) to tiredness and boredom

(dullness) or fatigue (weakness). Thus they are more reliable than human beings.

Versatility : Computers can perform repetitive jobs efficiently. They can work with different types of data and information like graphic, audio, visual, characters etc.

Disadvantage: Lack of Decision Making Power: Computers cannot decide on their own.

They do not have this power which is a great asset of human beings. IQ Zero: Computers are dumb machines with zero IQ. They need to be told

each and every step.

EVOLUTION OF COMPUTER

Year Device Inventor

Description

3000 BC ABACUS China The first mechanical calculating device in the history of computer.

1600 Arabic math China (1234567890) numbers are began to used in counting.

1614 Logarithm John Napier

Used in calculating big numbers.

1642 Mechanical Calculator or Pascaline

Blasé Pascal

Used o add two numbers

1673 Advanced Pascaline

Gottfried Wilhelm

Used to perform addition, subtractions, multiplication, division.

1801 Jacquard’s Loom

Joseph M. Jacquard’s

Used to store information based on principle of Punch cards.

1812 Differential Engine

Charles Babbage

I/O unit, Calculation Unit, Memory Unit

1816 Analytical Engine

Charles Babbage

Advanced version of Differential Engine. Now it can do 60 additions in one minute.

NOTE: CHARLES BABBAGE IS CALLED FATHER OF COMPUTER BECAUSE HE WAS THE FIRST PERSON WHO IMAGINE ABOUT STORED PROGRAM CONCEPT.

EVOLUTION OF COMPUTERYear Device Inventor Description

1872 Calculator Frank Boldwin Used for normal calculation

1890 Electro Card Herman Hollerith Punch cards used in first electro Card Machine

1908 Parallel Punching Machine

James Power Used to store data

1910 Tabulator Machine

Herman Hollerith Used in census of America

1942 Mechanical Analog Computer

Venever Bush Work on physical values as temperature, Pressure, Current etc. instead of digits.

1944 Electrical Analog Computer

Venever Bush Used in chemical plants, petroleum refineries, aircraft and electronic power plants.

1945 Digital Computer

Turing The First digital Computer

1946 ENIAC J.P. Eckert and John Mauchly

The first electronic digital Computer stands for (Electronic Numerical Integrator and Calculator)

1947 EDVAC Von Newman It stands for (Electronic Discrete Variable Automatic Computer). It stores instructions alongwith data.

1948 EDSAC Mauris Wilkes It stands for ( Electronic Delay Storage Automatic Calculator) . It calculates very fast.

Functional Components of Computer

Input Unit:

◦ It reads the data from the outside world.

◦ It converts these data in computer acceptable form.

◦ It supplies the converted data to the computer system for further processing.

◦ Computer uses input unit for data entry and instructions feeding purposes. Some of the input devices are keyboard, mouse, MICR, OCR, OMR, Scanner, joystick , light pen, bar code reader etc.

CPU (Central Processing Unit):

◦ It consists of ALU (Arithmetic Logic Unit) , CU (Control Unit) and Memory Unit.

◦ It is also called the heart of the computer. It directs the operation of the I/O devices.

Output Unit:

◦ It accepts result produced by the computer.

◦ It converts these data in human acceptable form.

◦ It supplies the converted data to the outside world.

◦ The result given by the computer is called output . It can be obtained on output devices like monitor, printer, plotter etc.

Computer Generations

Base I Gen. II Gen. III Gen. IV Gen. V Gen.

Period 1947-58 1959-64 1965-75 1976-90 1991-2001

Electronic Component

Vacuum Tubes

Transistor Integrated Circuits (IC)

LS -IC VLS-IC

Access Time

Milliseconds Microsecond (

Nanosecond Nanosecond Nanosecond

Memory (Min.)

20 KB 128KB 1MB 16MB 256MB

Speed 300 IPS 300 IPS 1 MIPS 8 MIPS 100 MIPS

Languages Machine BASIC,COBOL FORTRAN C & C++, ADA

Java, dotNet

Storage Device

Magnetic Drum

Magnetic Tape

Magnetic Core

Semi-conductor

Optical

Examples IBM 650ENIACEDSAC, EDVAC

IBM 704ICT 1300

IBM 360,1401ICL 1900

IBM 3081SPECTRA-70CRAY-I

CRAY-IV INTEL P I-IVPARAM

Classification of Computers

On the Basis of Purpose

• General• Special

On the basis of

Application• Analog• Digital• Hybrid

On the basis of

Size• Micro• Mini• Mainframe• Super

Note: General computers are used for ordinary tasks like banking , pay-roll systems.Special computers are used for specific task like space research, weather forecasting, traffic control etc.Analog computers work on physical values and transmits signal constantly. Example – Petrol Pump where analog computer displays quantity & price of Petrol.Digital Computers work only on binary digits and transmit signals discretely (isolated). Hybrid computer is combination of both analog & digital computers. These are very costly and mainly used in hospitals to measures the BP/Temp/ other symptoms of Patients.

Comparison of Computer based on Size

Types

RAM (Min.)

HDD (Min.)

Word-length

Speed (Min)

OS Usage Example

Micro 8-64 MB 10-100 GB

8-32 bit 100 MIPS

Windows Home Intel Pentium

Mini 64-128MB

100-200GB

32-64 bit 200MIPS Windows, Unix

Bank IBM 6000PDP-8

Main Frame

128-256MB

200-500 GB

64-128 bit

500 MIPS

Windows, Linux

Railway IBM 4300 HP 9000

Super

256-1024MB

500-1000 GB

128-256 bit

1000 MIPS

Unix, Mac

Research& aircraft

CRAY, HITAC, CYBER 205, PARAM

PARAM was India’s first super computer built by C-DAC Pune in guidance of Dr. Vijay P. Bhatnagar & Team. PARAM 10000 is the latest version of PARAM which provides weather report of one day within 01 minute and is the largest super computer of Asia.PACE (Processor for Aerodynamic Computation and Evaluation)was another Indian super computer produced by ANURAG (Advanced Numerical Research & Analysis Group)

Other Computer Types In recent years, design changes have reduced the size of micro

computers, making computer technology portable and affordable. Laptop computers are roughly the size of a large notebook. PC (Personal Computer) defines a computer designed for general use

by a single person. Desktop : PC that is not designed for portability. Palmtop: also known as PDAs (Personal Digital Assistants) that use

flash memory instead of a hard drive for storage. Workstation: a desktop computer that has a more powerful

processor and additional memory, such as 3D graphics or game development.

Server: A computer that has been optimized to provide services to other computers over a network.

Client: A computer that sends request for some information to the Server over a network.

Wearable: The latest trend in computing is wearable computers, which have applications like (e-mail, multimedia) etc.

Ex.- cell phones,

Computer SoftwareSystem Software

Operating System

Utilities

Language Processor

Assembler

Compiler

Interpreter

Application Software

Word Processing

Spreadsheets

DBMS

Graphics

Browsers

Operating System OS is a set of programs that operates all activities of

computer system. An OS is prepared to increase the efficiency of computer system. It is a link between user and hardware.

Functions of Operating System:◦ Memory Management: decides where and How files will be

stored in memory.

◦ Processor Management: Provides various tasks to CPU.◦ I/O Management: Performs various I/O functions.

◦ File Management: Transfers and arranging of files.◦ Communication: provides communication between user

and Screen.

◦ Internal time Control: operates internal system clock.

Memory ManagementThe different types of policies & techniques for memory management

are:◦ Single Contiguous Allocation: it is the simplest allocation

technique. But has the poor usage of Processor and main memory.

◦ Partitioned Allocation: it allows more than one job in the main memory at one time. But increases the complexity of the OS. It is the simplest for supporting the multiprogramming.

◦ Paged Memory Allocation: In this each job is divided into pieces of the same size, called pages. The physical memory is divided into pieces of same size called blocks. Any page can be placed into any block. This scheme eliminates fragmentation and increases memory and processor utilization. But it slow down the processor and increases cost of system.

◦ Demand Paged Allocation: When a page is needed in main memory, the page which are loaded on demand, are present on Hard Disk. This is known as Demand Paged Allocation. It is beneficial when we have large virtual memory and some times it makes processor overloaded.

Process Management We know that program is a set of instructions written in a programming

language. Process is a state of a program in execution. Or process is running

program with some specific tasks to do. A program is a passive entity whereas a process is an active entity. When OS creates and kills processes it is called Process Tree. The life time of a process can be divided in to 5 states:

◦ New: The process has been created.

◦ Ready: The process is waiting to be allocated to a processor.

◦ Running : Instructions are being executed. When a process gets a control from CPU , it starts executing.

◦ Suspended : A suspended process lacks some resource other than the CPU. Such processes are normally not considered for execution until the related suspending conditions is fulfilled.

◦ Terminate: When the Process finally stops. A process terminates when it finishes executing its last statement.

The OS groups all information that it needs about a particular process into a data structure called PCB (Process Control Block)

It contains Process No., Priority No., Process State and Program Counter.

Process Scheduling Scheduling refers to a set of techniques supported by

operating system that controls the order in which the work to be done is completed.

The main objective of scheduling is to increase CPU utilization and performance.

We have to use some performance criteria to maximize the system performance . These are:◦ Throughput: it is measure of amount of work completed in a given

time interval. Higher throughput means better system performance. It can be calculated by using the formula The no of jobs completed / Total time to complete the jobs

◦ Time slice / Time Quantum : a small unit of time (in milliseconds) given to a process by CPU.

◦ Turnaround Time: It is the delay between job submission and job completion.

◦ Waiting Time: It may be expressed as turnaround time, less than the actual processing time.

Types of Scheduling Non-Pre-emptive : In this Scheduling , Scheduled job

always completes before another scheduling decision is made. Therefore, finishing order of the jobs is also same as their scheduling order. The following Techniques use Non-Pre-emptive Scheduling:◦ FCFS (First Come First Served)

◦ SJF (Shortest Job First) or SJN (Shortest Job Next)

◦ Deadline Scheduling

Pre-emptive Scheduling: In this a Scheduling decision can be made even while the job is executing . It is more useful in high priority, which requires immediate response. The following Techniques use Pre-emptive Scheduling:◦ Round Robin Scheduling

◦ Response Ratio Scheduling

Scheduling Techniques FCFS(First Come First Serve): This is the simplest scheduling

technique which is managed by FIFO (First In First Out) queue. i.e. The Process which requests the CPU first, is allocated the CPU First. ◦ The CPU executes the jobs in the ready queue one by one.

◦ Batch Processing is one obvious example of FCFS Technique in which all jobs in the batch are executed one by one. But Turnaround time for the very first job in the batch is the best and for the very last job it is worst.

SJF/SJN : In this technique, whenever a new job is to be admitted, the shortest of the arrived jobs is selected and given the CPU time. Throughput remains the same as in FCFS scheduling but waiting time improves. SJN associates with each job the length of its next CPU burst. (CPU burst is the CPU time required by a job to execute its continuous executable part.)

DEADLINE : In deadline scheduling the job with earliest deadline is selected for scheduling. Deadline of a job is the time limit within which a job must be over. If a job overshoots its deadline, it is said to be Deadline over run. Deadline over run is calculated as K=C-D where K is Deadline overrun ; C is job completion time and D is Deadline for a job.

Scheduling Techniques…ROUND ROBIN : Round Robin (RR) Scheduling is aimed

at giving all programs equal opportunity to make progress. This is implemented by ensuring that no program gets a second opportunity to execute unless all other programs have had at least one opportunity. ◦ A small unit of time, called a time quantum or time slice, is

defined. The ready queue (queue of programs waiting for CPU time )is treated as a circular queue. The programs in the ready queue are processed for the defined time slice, one by one.

RESPONSE RATIO : Response Ratio is calculated as follows Response Ratio =Elapsed

time / Execution time received

The job with highest response ratio is preferred over others. When a short job arrives, its response ratio is high, it is scheduled for execution immediately. A longer job would achieve high enough ratio only after a subsequent wait.

TYPES OF OPERATING SYSTEMs

SINGLE USER: Single user operating system is a type of operating system which allows only one user at a time. ◦ The most popular single user OS is MS DOS (Microsoft Disk Operating System).

MULTIPROCESSING : In this OS two or more independent Processors are linked together in a coordinated system and the instructions are executed simultaneously.◦ It is used for major control applications like Rail , Road and Airways.

MULTIPROGRAMMING: In this OS more than one user programs are executed at the same time. It increases the resource utilization of CPU.◦ It is used to support multiple interactive tasks simultaneously.

Some Popular Operating Systems: MSDOS, UNIX,WINDOWS , LINUX. Mac, BOSS, Solaris…

TYPES OF OPERATING SYSTEMs

Time Sharing: This OS operates in an interactive mode with a quick response time. The user sends a request and the OS processes it and a response is displayed.

Real Time: In this OS the jobs have fixed deadlines and the jobs have to be completed within their deadlines. It is used in Airlines booking, Wholesale market and manufacturing to see the current status.

Distributed : In this OS , the user can access remote resources in same manner as they do local resources. Data and process migration from one site to another is under the control of this OS.◦ It is used for Resource Sharing, Load Sharing, Reliability and

Communications. Network OS: it is used to support networking and servers. It

provides file sharing , print sharing, backup of data etc.◦ Example : Windows NT server, Windows 9x, OS/2 and Macintosh

Internal Parts of Computer Microprocessor: is a computer processor on a microchip

made of silicon metal. It is sometimes called a logic chip. Intel 4004 was the first Microprocessor. It has four major components like:◦ Control Unit : it controls all the functions like input ,

output , storage and process.◦ Arithmetic Logic Unit: it is capable to perform

addition ,subtraction, multiplication, division as well as comparisons.

◦ Register: it is a special temporary storage location within the CPU. To execute an instruction , the CU retrieves it from main memory and places it into a register.

◦ BUS: it refers to an electrical pathway through which bits are transferred between the various computer components. Or we can say a bus is a collection of wires over which the computer sends information.

Internal Parts of Computer… Clock Speed: it refers to the no. of pulses per second generated

by an oscillator (Alternator). Usually it is measured in MHz (Megahertz pulses per second).

Processor: is the logic circuitry that responds to and processes the basic instructions that drive a computer. These have 8 to 64 bit word lengths. These are divided in two categories: RISC & CISC.

RISC CISC

Reduced Instruction Set Computer

Complex Instruction Set Computer

All HLL support is done in Software

All HLL support is done in Hardware

Simple , Single-Cycle Instructions set that perform only basic functions

Large and Varied instructions set that perform simple and complex tasks

Direct execution control unit A microcode control unit

Spend more transistors on registers

Spend fewer transistors on registers

Example: Apple, Mac G3, PowerPC

AMD, Cyrix and Intel

Internal Parts of Computer…System Bus: it carries bits between CPU and

only one peripheral at a time. There are three main buses: ◦ Data Bus: it is an electrical path that carries 32 bits of

data at once between CPU and Memory and vice versa.◦ Address Bus: it carries 32 bits memory address to

read/ write from Memory to CPU.◦ Control Bus: it carries signals created by processor and

other devices. PCI ( Peripheral Component Interconnect) is a data bus standard

developed by Intel Corporation. It is a 64 bit bus with 66 MHz speed. We can add various devices through it.

EISA ( Extended Industry Standard Architecture) is also a data bus standard developed by Compaq. It is a 32 bit bus and useful for multiprocessing and multitasking. It is expensive but has better data transfer rate.

Various Registers:Register Functions

Accumulator To store numbers and arithmetic calculations

Program Counter

To store the address of the instructions which has to be executed next.

Decoder To decode and interpret the instructions given to computer through input.

Memory Address Register (MAR)

To contain the address of a word currently required and to fetch next instruction.

Memory Buffer Register (MBR)

To store a word as it is read from memory and to place the instructions in MAR.

Instruction Register

To handle instruction and data at a speed about 10 times faster than other registers and to generate the required signals.

INPUT DEVICESDevice-Name UsageKeyboard The main input device that is used to enter data into computer. It

has 104 keys.

Mouse A handheld pointing device that controls curser position on the screen.

OCR Optical Character Reader is a input device used to read handwritten and printed documents.

OMR / ORS Optical Mark Recognition is used to scan a printed form and reads predefined positions of records. ORS (Optical Response Sheet)

MICR Magnetic Ink Character Recognition is used to read special symbols printed on a cheque in the banks.

Light Pen It is used to draw lines or curve on the screen. Mostly used for graphics works.

Joystick Just like a mouse, mostly used for computer games

New Devices Now a days, the following input devices are mostly used :- smart card, bar code readers, Bio-metric sensors, Graphic Tablets and scanners.

Output DevicesDevice-Name

Usage

Monitor The main output device which displays information on screen. Also known as LCD,CRT, VDU , TFT, Monochrome. It many adapters that decides the picture quality based on resolution and pixels. SVGA (Super Visual Graphics Adapter) with 640x480 (640 pixel and 480 rows), 256 colors

Printer It prints an output on paper. Also known as hardcopy. These are of two types: (i) impact (ii) Non-Impact.

Impact The impact printers work like electronic typewriter in which a key is pressed to take impress of Ink on Paper. Example: DMP, Line Printer ,Drum Printer , Daisy Wheel etc.

Non-impact While in a Non-impact there is no need of pressing key to take impression of Ink. It use photo sensitive technology. Example: Inkjet, Laser

Plotters Used to print big pictures or maps of buildings, master plans and to create 2-D/3-D graphs.

Memory

Introduction: After CPU, memory is the most important part. Memory is the place where data & instructions are stored.

Types of Memory: ◦ Primary (Main) Memory◦ Secondary (Auxiliary) Memory◦ Cache Memory

Primary Memory is the internal part of computer. Data & instructions are stored on electronic circuits. It is also called semi-conductor memory. It can be of two types:◦ RAM (Random Access Memory)◦ ROM (Read Only Memory)

RAM v/s ROMRandom Access Memory Read Only Memory

It is a temporary memory. It is a permanent memory

We can read & write data in it. Information can be only read in it.

It is a volatile memory because when power is off, the data are lost.

It is Non-Volatile. So information remains safe even when power is off.

Operating System is loaded in it at booting time.

The information is written at the time of manufacturing by the programmers

Transistors & capacitors are the main part of RAM.

The user cannot change the programs of ROM.

Data are kept in Row & Columns in it. It is also used in automatic washing machine & toys.

Static ,Dynamic, DDR are types of it. PROM,EPROM,EEPROM are types of it.

Static RAM: (SRAM)◦ Data are stored

permanently.◦ Expensive but fast.◦ Useful in multi-media.◦ No need of refreshing.◦ Used in cache memory & PC.

Dynamic RAM: (DRAM)◦ Data are transferred like

electronic current.◦ Data are kept in micro-

capacitors.◦ Refresh is essential otherwise

data will be destroyed after sometime.

Types of RAM

EDO RAM: (Extended Data Out)

◦ Advance form of DRAM◦ Used in Pentium-I PCs◦ Faster than DRAM.

SD RAM: (Synchronous DRAM)

◦ Faster than EDO RAM◦ Used in Pentium-II & III PCs◦ Increased access speed in MHz

RDRAM (Rambus DRAM): is the high speed memory but very expensive. DDR RAM (Double Data Rate RAM): is the latest memory used in recent PCs.

Types of ROM• PROM:

– Programmable ROM– User can store

programs only once.– User can make micro

code program can be made that are needed mostly.

– The process of making program in PROM is called ‘Burning’.

– Example: CD-R

• EPROM:– Erasable PROM– Information can be

removed by ultra violet rays.

– Information can be re-write after removing previous information.

– It is cheaper than PROM because it is re-useable.

– Example: CD(RW)

EEPROM:◦ Electrically Erasable

PROM◦ Information can be

removed by electric signals.

◦ It is the simplest way to store info in ROM.

◦ Now it is used to store BIOS in Memory.

◦ Example :Pen Drive

Cache Memory: is a semi-conductor (buffer)memory which lies between main memory and processor. It is mainly used for increasing the speed of RAM.

Secondary Storage DevicesDevices Usage

Magnetic Disk It offers high storage capacity, reliability and the capacity to directly access stored data.

Floppy Disk These are quite cheap and allow to copy files from one computer to another. Available in different size : 8-inch,5.25- inch and 3.5-inch. But have a limited capacity.

Hard Disk It is a disk storage device having very large capacity in GB with a mechanism for reading & writing to the hard disk.It is divided in to Tracks , Cylinders and Sectors.

Optical Disks The following optical disks are available in markets which are mostly used to store, record and play multimedia files.CD-ROM (Compact Disk Read Only Memory)DVD (Digital Versatile/Video Disk) ; Blue Ray Disk WORM (Write Once Read Many) also called CD-R.

Zip Drive It is a great replacement of Floppies. These are expensive and come with USB interface. These are portable , fast and easy to use.

Pen Drive/Flash Memory It is a memory chip that is portable, fast and easy to use and. Also known as removable disk. Mostly used for storing and transferring data from one computer to another.

Bluetooth It is a short range wireless technology used for connecting and transferring data between two devices.

Various Ports of ComputersPorts Usage

Serial Port Generally, in a motherboard there are two serial ports. One serial port is for a serial mouse and another is for external modem.

Parallel Port It a connector through which a computer communicates with impact Printers. Almost all motherboard provide one parallel port.

USB Port Universal Serial Bus- is a bus standard becoming more common everyday. Now-a-days almost devices are connected through these ports.

PS-2 Port It is mostly used to connect keyboard, mouse, trackball and touch pad.

SCSI Port It is a High Density 30- pin connector set on a motherboard, used to connect external hard disk or a removable disk.

Infrared Port It is a wireless technology used to connect a computer and a device to communicate each other. For this a IR adapter and Software installation required. Example: Wireless Keyboard/mouse.

Terms used in Computers Buffer: it is a temporary storage area. A buffer will take information

from one device and hold it until another device is ready to receive it. Spooling: The collection of information from several sources at one

point, followed by orderly delivery of that information to the device. E.g. a printer .

Access Time: is the time from the start of one storage device access to the time when the next access can be started.

Seek Time: is the time to position the head on a specific track on a fixed head disks. It is the time taken by electronic circuit to select the required head.

Latency Time: The time required by a sector t reach below the R/W head. On an average.

Heatsink: is a device that is attached to a microprocessor chip to keep it from overheating by absorbing its heat and dissipating (dissolve) it into the air. There are two types of heatsink.

(i) Active heatsink that comes with a Fan.

(ii) (ii) Passive heatsink that comes without fan.