mishqen college department of ict this module covers: introducing information and communication...

Information and Communication

Technology (ICT)

Supportive Module - 1

MISHKEN COLLEGE

Mishqen College Department of ICT

Module Description

• This Module Covers:• Introducing Information and

Communication Technology (ICT)• Basics of Computers• Computer data representation and

numbering System• Basics of Data Communication• Computer Networking• Computer Hazards and Security

LEARNING OUTCOMES (OBJECTIVES)

• At the end of the module the learner will be able to:• Understand the constituents of

Information and Communication Technologies, familiarized with computer systems and application areas of IT and, link it with the subsequent vocational training modules.


Relationship to Unit of Competence Standards

• This Module is related with all competencies found in the EOS• ICT ITA S01 0108 Operate a personal computer• ICT ITA S02 0108 Migrate to new technology• ICT ITA S03 0108 Advice clients and provide first-level remote help desk

support• ICT ITA S04 0108 Protect computer hardware & application or system

software• ICT ITA S105 0108 Connect hardware peripherals • ICT ITA S06 0108 Support system software• ICT ITA S07 0108 Determine and take action client computing and network

problems• ICT ITA S08 0108 Implement maintenance procedures• ICT ITA S09 0108 Maintain equipment and software in working order• ICT ITA S10 0108 Install software applications• ICT ITA S11 0108 Create technical documentations• ICT ITA S12 0108 Record client support requirements• ICT ITA S13 0108 Maintain inventories for equipment, software &

documentation• ICT ITA S14 0108 Apply problem solving techniques to routine malfunctions


Module Contents at Glance

• Introducing Information and Communication Technology (ICT) Introduction to Information Technology Information and Data Processing Basics of Information Systems

• Basics of Computer System Definition, Concepts, History and evolution of Computers Types of Computers Characteristics of Computers Application of Computers Computers and Hunan Beings

• The Computer System The Computer Hardware The Computer Software



• Computer Data Representation and Numbering ystem Units of Data Representation The Numbering System Coding Systems (Schemes)

• Basics of Data Communication Overview of Data Communication Components of Data Communication System

• Basics Computer Networking Concepts and Importance of Computer Networking Types of Network Components of Network Network Architectures Basics Concepts of the Internet Basic Concepts of Intranet Versus Extranet

Mishqen College Department of

ICT


Network Layers, Protocols and Standards• Computer Hazards and Security

Physical Computer Hazards and Security Logical Computer Hazards and Security Computer Ethics


Chapter Two

Basics of Computers



Objectives of this Chapter

After the end of these Chapter, trainees will be able to: Define what computer is Understand the four basic computer operations Understand characteristics of computers Explain the computers evolution and their historical

development Identify the different types of currently used computers Discuss the capabilities of computers Explain how data is organized Discuss the applications of computers Identify the limitation of computers Comparing human being with computers


Basic Concepts About Computer

What is Computer? Computer is electronic device, operating under the control

of instructions stored in its own memory unit, which can accept data (input), manipulate the data according to special rules (process), produce information (output) from the processing, and store the results for future use.

Computer is a collection of devices that function together as a system.

Computer is an electronic data processing machine that’s designed and organized to automatically accept and store data, process them, and produce output under the direction of a stored detailed step-by-step sets of instruction.

Computer is a programmable electronic device. Computer is a system composed of hardware and

software components.


History and Evolution of Computers

The Origins Prehistoric man did not have the Internet, but it appears

that he needed a way to count and make calculations. The limitations of the human body’s ten fingers and ten

toes apparently caused early man to construct a tool to help with those calculations.

Scientists now know that humankind invented an early form of computers.

Their clue was a bone carved with prime numbers found in 8,500 BC.

The abacus was the next leap forward in computing between 1000 BC and 500 BD.

This apparatus used a series of moveable beads or rocks. The positions changed to enter a number and again to

perform mathematical operations.



Leonardo DaVinci was credited with the invention of the world’s first mechanical calculator in 1500.

In 1642, Blaise Pascal’s adding machine upstaged DaVinci’s marvel and moved computing forward again.

In 19th century England, Charles Babbage, a mathematician, proposed the construction of a machine that he called the Babbage Difference Engine.

It would not only calculate numbers, it would also be capable of printing mathematical tables.

The Computer History Museum in Mountain View, CA (near San Diego) built a working replica from the original drawings.

Visitors can see in the device in operation there. Unable to construct the actual device, he earned quite a few

detractors among England’s literate citizens. However, Babbage made a place for himself in history as the

father of computing.



Not satisfied with the machines limitations, he drafted plans for the Babbage Analytical Engine.

He intended for this computing device to use punch cards as the control mechanism for calculations.

This feature would make it possible for his computer to use previously performed calculations in new ones.

Babbage’s idea caught the attention of Ada Byron Lovelace who had an undying passion for math.

She also saw possibilities that the Analytical Machine could produce graphics and music.

She helped Babbage move his project from idea to reality by documenting how the device would calculate Bernoulli numbers. She later received recognition for writing the world’s first computer program.

The United States Department of Defense named a computer language in her honor in 1979.



The computers that followed built on each previous success and improved it.

In 1943, the first programmable computer Turing COLOSSUS appeared.

It was pressed into service to decipher World War II coded messages from Germany.

ENIAC, the brain, was the first electronic computer, in 1946.

In 1951, the U.S. Census Bureau became the first government agency to buy a computer, UNIVAC .

The Apple expanded the use of computers to consumers in 1977.

The IBM PC for consumers followed closely in 1981, although IBM mainframes were in use by government and corporations.



8,500 BC Bone carved with prime numbers found 1000 BC to 500 BC Abacus invented 1642 Blaise Pascal’s invented adding machine, France 1822 Charles Babbage drafted Babbage Difference Engine, England 1835 Babbage Analytical Engine proposed, England 1843 Ada Byron Lovelace computer program to calculate Bernoulli numbers,

England 1943 Turing COLOSSUS the first programmable computer, England 1946 ENIAC first electronic computer, U.S.A. 1951 UNIVAC first computer used by U.S. government, U.S.A. 1969 ARPANET Department of Defense lays groundwork for Internet, U.S.A. 1968 Gordon Moore and Robert Noyce found in Intel, U.S.A. 1977 Apple computers for consumers sold, U.S.A. 1981 IBM personal computers sold, U.S.A. 1991 World Wide Web consumer Internet access, CERN, Tim Berners-Lee

Switzerland/France 2000 Y 2K Bug programming errors discovered Current Technologies include word processing, games, email, maps, and

streaming



Abacus (5000BC) The first mechanical calculator with moving parts, which

used in performing arithmetic calculations.

Abacus



The Slide Rule (1632) Slide rule is a complex mechanical calculating device used

for logarithmic and compound interest calculations. It was invented by William Oughtred

Slide Rule



Pascal’s Calculator (1642) It was a mechanical calculating device used to perform

addition and subtraction only. Pascal's device used a series of toothed wheels, which

were turned by hand and which could handle numbers up to 999,999.999.

Pascal's device was also called the "numerical wheel calculator" and was one of the world's first mechanical adding machines.

Pascaline Calculator



Babbage’s Engines (1822) It was invented by Charles Babbage, British

Mathematician It was a multiple adding machine, designed to compute

and print tables of polynomials by repeated addition of differences.

Babbage invented two different engines which was considered as the forerunner of the modern computer, Differential and Analytical engines.


Generations of Computers

The history of computer development is often referred to in reference to the different generations of computing devices.

Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices.

Depending on the type of materials used and facilities available, the development of electronic computers are classified into five generations. First Generation Computers (1990-1959) Second Generation Computers (1956-1963) Third Generation Computers (1964-1971) Fourth Generation Computers (1971-Present) Fifth Generation Computers (Present and Beyond)


First Generation Computers (1940-1956) The age of Vacuum Tube

The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms.

They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time.

Input was based on punched cards and paper tape, and output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing devices.

The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.



UNIVAC


First Generation Computers (1940-1956) The age of Vacuum TubeVacu

um

Tu

bes

UNIVAC Vacuum Tube -- Shown are vacuum tube rectifiers of the type used in early UNIVAC computer power supplies.

The UNIVAC was produced in the 1950's by Remington Rand Univac.



ENIAC (Electronic Numerical Integrator and Computer), the first electronic computer that could handle large scale calculations. The 28-ton device, with nearly 18,000 vacuum tubes, could crank 5,000 addition problems in a second, and was used on projects relating to hydrogen bomb development. For comparison, an Intel Core Duo chip does about 21.5 billion operations per second.

Fine-tuning ENIAC. J. Presper Eckert (the man in the foreground turning a knob) served and John Mauchly (center) designed ENIAC to calculate the trajectory of artillery shells. The machine didn’t debut until February 1946, after the end of World War II, but it did launch the computer revolution.



Machine Language The lowest-level programming language (except for computers

that utilize programmable microcode) Machine languages are the only languages understood by computers.

While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers.

Programmers, therefore, use either a high-level programming language or an assembly language.

An assembly language contains the same instructions as a machine language, but the instructions and variables have names instead of being just numbers.

Programs written in high-level languages are translated into assembly language or machine language by a compiler.

Assembly language programs are translated into machine language by a program called an assembler.

Every CPU has its own unique machine language. Programs must be rewritten or recompiled, therefore, to run on different types of computers.


Second Generation Computers (1956-1963) The age of Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers.

The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s.

The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors.

Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.

Second-generation computers still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words.



High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN.

These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

The first computers of this generation were developed for the atomic energy industry.

Transistors amplify current, for example they can be used to amplify the small output current from a logic IC so that it can operate a lamp, relay or other high current device.

In many circuits a resistor is used to convert the changing current to a changing voltage, so the transistor is being used to amplify voltage.

A transistor may be used as a switch (either fully on with maximum current, or fully off with no current) and as an amplifier (always partly on).



Transistors



Transistor A device composed of semiconductor material that

amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become

the key ingredient of all digital circuits, including computers.

Today's microprocessors contains tens of millions of microscopic transistors.

Prior to the invention of transistors, digital circuits were composed of vacuum tubes, which had many disadvantages.

They were much larger, required more energy, dissipated more heat, and were more prone to failures.

It's safe to say that without the invention of transistors, computing as we know it today would not be possible.


Third Generation Computers (1964-1971) The age of Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers.

Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.

Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.


Integrated Circuit Another name for a chip, an integrated circuit (IC) is a small electronic

device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of

Texas Instruments and Robert Noyce of Fairchild Semiconductor. Integrated circuits are used for a variety of devices, including

microprocessors, audio and video equipment, and automobiles. Integrated circuits are often classified by the number of transistors and

other electronic components they contain: SSI (small-scale integration): Up to 100 electronic components per

chip MSI (medium-scale integration): From 100 to 3,000 electronic

components per chip LSI (large-scale integration): From 3,000 to 100,000 electronic

components per chip VLSI (very large-scale integration): From 100,000 to 1,000,000

electronic components per chip ULSI (ultra large-scale integration): More than 1 million electronic

components per chipMishqen College Department of ICT



Silicon A nonmetallic chemical element in the carbon family of elements. Silicon - atomic symbol "Si" - is the second most abundant element in

the earth's crust, surpassed only by oxygen. Silicon does not occur uncombined in nature. Sand and almost all rocks contain silicon combined with oxygen,

forming silica. When silicon combines with other elements, such as iron, aluminum or

potassium, a silicate is formed. Compounds of silicon also occur in the atmosphere, natural waters,

many plants and in the bodies of some animals. Silicon is the basic material used to make computer chips, transistors,

silicon diodes and other electronic circuits and switching devices because its atomic structure makes the element an ideal semiconductor.

Silicon is commonly doped, or mixed, with other elements, such as boron, phosphorous and arsenic, to alter its conductive properties.

Silicon was first isolated and described as an element in 1824 by Jöns Jacob Berzelius, a Swedish chemist.



Chip A small piece of semiconducting material (usually silicon) on which an

integrated circuit is embedded. A typical chip is less than ¼-square inches and can contain millions of electronic

components (transistors). Computers consist of many chips placed on electronic boards called printed

circuit boards. There are different types of chips. For example, CPU chips (also called microprocessors) contain an entire

processing unit, whereas memory chips contain blank memory. Chips come in a variety of packages. The three most common are:

DIPs : Dual in-line packages are the traditional buglike chips that have anywhere from 8 to 40 legs, evenly divided in two rows.

PGAs : Pin-grid arrays are square chips in which the pins are arranged in concentric squares.

SIPs : Single in-line packages are chips that have just one row of legs in a straight line like a comb.

In addition to these types of chips, there are also single in-line memory modules (SIMMs), which consist of up to nine chips packaged as a single unit.



Semiconductor A material that is neither a good conductor of electricity

(like copper) nor a good insulator (like rubber). The most common semiconductor materials are silicon

and germanium. These materials are then doped to create an excess or

lack of electrons. Computer chips, both for CPU and memory, are composed

of semiconductor materials. Semiconductors make it possible to miniaturize electronic

components, such as transistors. Not only does miniaturization mean that the components

take up less space, it also means that they are faster and require less energy.


Fourth Generation Computers (1971-Present) The Age of Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.

What in the first generation filled an entire room could now fit in the palm of the hand.

The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.

In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh.

Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet.

Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.



Microprocessor A silicon chip that contains a CPU. In the world of personal computers, the terms microprocessor and CPU are

used interchangeably. At the heart of all personal computers and most workstations sits a

microprocessor. Microprocessors also control the logic of almost all digital devices, from clock

radios to fuel-injection systems for automobiles. Three basic characteristics differentiate microprocessors:

Instruction set: The set of instructions that the microprocessor can execute.

bandwidth : The number of bits processed in a single instruction. clock speed : Given in megahertz (MHz), the clock speed determines

how many instructions per second the processor can execute. In both cases, the higher the value, the more powerful the CPU. For example, a 32-bit microprocessor that runs at 50MHz is more powerful

than a 16-bit microprocessor that runs at 25MHz. In addition to bandwidth and clock speed, microprocessors are classified as

being either RISC (reduced instruction set computer) or CISC (complex instruction set computer).



CPU Pronounced as separate letters it is the abbreviation for

central processing unit. The CPU is the brains of the computer. Sometimes referred to simply as the central processor,

but more commonly called processor, the CPU is where most calculations take place.

In terms of computing power, the CPU is the most important element of a computer system.

On large machines, CPUs require one or more printed circuit boards.

On personal computers and small workstations, the CPU is housed in a single chip called a microprocessor.

Since the 1970's the microprocessor class of CPUs has almost completely overtaken all other CPU implementations.



CPU The CPU itself is an internal component of the computer. Modern CPUs are small and square and contain multiple metallic

connectors or pins on the underside. The CPU is inserted directly into a CPU socket, pin side down, on

the motherboard. Each motherboard will support only a specific type or range of

CPU so you must check the motherboard manufacturer's specifications before attempting to replace or upgrade a CPU.

Modern CPUs also have an attached heat sink and small fan that go directly on top of the CPU to help dissipate heat.

Two typical components of a CPU are the following: The arithmetic logic unit (ALU), which performs arithmetic and

logical operations. The control unit (CU), which extracts instructions from

memory and decodes and executes them, calling on the ALU when necessary.


Fifth Generation Computers (Present and Beyond)

The Age of Artificial Intelligence Fifth generation computing devices, based on artificial

intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.

The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come.

The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.



The Age of Artificial Intelligence Artificial Intelligence

The branch of computer science concerned with making computers behave like humans.

The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology.

Artificial intelligence includes: games playing: programming computers to play games such as

chess and checkers expert systems : programming computers to make decisions in

real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms)

natural language : programming computers to understand natural human languages

neural networks : Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains

robotics : programming computers to see and hear and react to other sensory stimuli



The Age of Artificial Intelligence Voice Recognition

The field of computer science that deals with designing computer systems that can recognize spoken words.

Note that voice recognition implies only that the computer can take dictation, not that it understands what is being said.

Comprehending human languages falls under a different field of computer science called natural language processing.

A number of voice recognition systems are available on the market.

The most powerful can recognize thousands of words. However, they generally require an extended training

session during which the computer system becomes accustomed to a particular voice and accent.

Such systems are said to be speaker dependent.


The Age of Artificial Intelligence Voice Recognition

Many systems also require that the speaker speak slowly and distinctly and separate each word with a short pause.

These systems are called discrete speech systems. Recently, great strides have been made in continuous speech

systems -- voice recognition systems that allow you to speak naturally.

There are now several continuous-speech systems available for personal computers.

Because of their limitations and high cost, voice recognition systems have traditionally been used only in a few specialized situations.

For example, such systems are useful in instances when the user is unable to use a keyboard to enter data because his or her hands are occupied or disabled.

Instead of typing commands, the user can simply speak into a headset.

Increasingly, however, as the cost decreases and performance improves, speech recognition systems are entering the mainstream and are being used as an alternative to keyboards.




The Age of Artificial Intelligence Parallel Processing The simultaneous use of more than one CPU to execute a

program. Ideally, parallel processing makes a program run faster

because there are more engines (CPUs) running it. In practice, it is often difficult to divide a program in such a

way that separate CPUs can execute different portions without interfering with each other.

Most computers have just one CPU, but some models have several. There are even computers with thousands of CPUs.

With single-CPU computers, it is possible to perform parallel processing by connecting the computers in a network.

However, this type of parallel processing requires very sophisticated software called distributed processing software.

Note that parallel processing differs from multitasking, in which a single CPU executes several programs at once.

Parallel processing is also called parallel computing.



The Age of Artificial Intelligence Quantum Computing

First proposed in the 1970s, quantum computing relies on quantum physics by taking advantage of certain quantum physics properties of atoms or nuclei that allow them to work together as quantum bits, or qubits, to be the computer's processor and memory.

By interacting with each other while being isolated from the external environment, qubits can perform certain calculations exponentially faster than conventional computers.

Qubits do not rely on the traditional binary nature of computing. While traditional computers encode information into bits using

binary numbers, either a 0 or 1, and can only do calculations on one set of numbers at once, quantum computers encode information as a series of quantum-mechanical states such as spin directions of electrons or polarization orientations of a photon that might represent a 1 or a 0, might represent a combination of the two or might represent a number expressing that the state of the qubit is somewhere between 1 and 0, or a superposition of many different numbers at once.


Quantum Computing A quantum computer can do an arbitrary reversible classical computation

on all the numbers simultaneously, which a binary system cannot do, and also has some ability to produce interference between various different numbers.

By doing a computation on many different numbers at once, then interfering the results to get a single answer, a quantum computer has the potential to be much more powerful than a classical computer of the same size.

In using only a single processing unit, a quantum computer can naturally perform myriad operations in parallel.

Quantum computing is not well suited for tasks such as word processing and email, but it is ideal for tasks such as cryptography and modeling and indexing very large databases.



The Age of Artificial Intelligence Nanotechnology

A field of science whose goal is to control individual atoms and molecules to create computer chips and other devices that are thousands of times smaller than current technologies permit.

Current manufacturing processes use lithography to imprint circuits on semiconductor materials.

While lithography has improved dramatically over the last two decades -- to the point where some manufacturing plants can produce circuits smaller than one micron (1,000 nanometers) -- it still deals with aggregates of millions of atoms.

It is widely believed that lithography is quickly approaching its physical limits.

To continue reducing the size of semiconductors, new technologies that juggle individual atoms will be necessary.

This is the realm of nanotechnology.



The Age of Artificial Intelligence Nanotechnology

Although research in this field dates back to Richard P.Feynman's classic talk in 1959, the term nanotechnology was first coined by K. Eric Drexler in 1986 in the book Engines of Creation.

In the popular press, the term nanotechnology is sometimes used to refer to any sub-micron process, including lithography.

Because of this, many scientists are beginning to use the term molecular nanotechnology when talking about true nanotechnology at the molecular level.



The Age of Artificial Intelligence Natural Language

A human language. For example, English, French, and Chinese are natural

languages. Computer languages, such as FORTRAN and C, are not. Probably the single most challenging problem in computer

science is to develop computers that can understand natural languages.

So far, the complete solution to this problem has proved elusive, although a great deal of progress has been made.

Fourth-generation languages are the programming languages closest to natural languages.


Summary of the Trend in the Development of Computers

The computers are getting smaller in volume and size. They dissipate less heat. They consume less power. They have large memory capacity. They have n=better execution speed and power. The computers are getting more reliable. They became more affordable and user friendly.


Types of Computers(Based on Capacity, speed and

reliability)1. Microcomputers (Personal Computers)

a. Palmtop Computersb. Laptop Computersc. Desktop computers

2. Minicomputers3. Mainframes4. Supercomputers


Microcomputers

Personal computers or Microcomputers are the most widely used computers which have found application in everyday activity of the modern world.

The speed and accuracy of processing of the personal systems account for their high popularity.

Think of a world where share market trading had to be carried out manually and the times when the fastest means of communication was but for the telephones were the telegrams.

Those days are not even past 50 years, yet you cannot imagine life without the aid of personal computers or “PCs” as you abbreviate them.

Personal computers remind us mostly of Desktop computers or at the most Laptop computers.

But actually Personal computers refer to:-


Microcomputers

Desktop computers Desktop Computers are those Personal computers that one

comes across in business institutions, ATM s, Offices, etc. They have the second largest market among all kinds of PCs.

They are nonportable and long lasting. Laptop computers

Laptop Computers are a personal system sub-type. As the name goes, it is a portable computer which is usually

a light weight PC. The special feature of course, is that it is far lighter than a

Desktop PC and being a wireless system, you can use it even when there is a power cut or you are away from home where electricity is not available.


Microcomputers

Hand held computers or palm tops Palm tops like laptops are portable personal computers which

are even smaller and lighter and can be carried in a pocket. Ideally a palmtop is used for storage of personal information

like phone numbers, appointments and the likes. Nowadays with the improvement of technology palmtops

come with colored monitors, sound recording facilities, and even provision for access to the Internet.

Tablet Personal Computers Tablet PCs are also a kind of micro computers. They are mostly used in Graphics work is an electronic device

that utilizes digital ink to write or draw directly on the monitor of you PC.


Microcomputers

Work Stations This is slightly different from the regular PC in respect that it

has evolved from the mini computers. Originally used for Engineering, Graphics and such other non-

personal work or technical work, work station computers were designed for the purpose of singular interaction of computer with one person at a time.

The personal computers or Microcomputers are manufactured by several multinational companies such as the HP computers, HCL, Del Inspiration, Acer, Toshiba and many more.


Microcomputers

Laptops

Desktop

Tablet PC

Palmtop PCWorkstation

PC


Minicomputers

Minicomputers, what exactly are they? If supercomputers and mainframes are considered to be the best in terms of mathematical operations then minicomputer systems succeed them.

Previously, minicomputers were considered to be superior to personal systems.

But these days, advancement in technology has made minicomputers almost obsolete because the PCs today are highly advanced.

The Minicomputers were first built in in 1960s and they immediately became a huge success as 40,000 of the minicomputer systems were immediately sold of making the computers hugely available to the general public.

With such a successful market possibility many companies stepped in to venture in the minicomputer market. The most successful among these two hundred companies was DEC that launched the minicomputer models PDP-11 and VAX 11/780.


Minicomputers

Some significant aspects and historical facts about the mini computer system has been summarized as follows: They are much smaller in size than the mainframe

computer systems. As such they do not occupy an entire room but usually

occupy space similar in size to that of a standard refrigerator.

They are much less expensive than the mainframes. Their invention was possible because of the invention of

core memory technologies and transistors. Minicomputers can give parallel access to up to 100 users.

Hence they were used in places such as business organizations for maintaining billings and finances.

Some of the very first companies to manufacture the minicomputer systems were Hewlett Packard, DEC and Data General.


Minicomputers A few models of minicomputers which have been a marked

success over the years are: DEC VAX series and PDP series Hewlett Packard HP3000 series SDS,SDS-92 Prime Computers, Prime 50 Series Norsk Data, Nord-1, Nord-10, Nord-100 IBM Midrange Computers Control Data Corporation's CDC 160A, CDC-1700 Data General Nova Honeywell-Bull Level 6/DPS Level6/DPS 6000 series

Minicomputers have eventually evolved in to microcomputers. With the launch of microcomputers, the public have had a greater access to the advantage of incorporating computers in the daily stride of their lives.


Minicomputers

Minicomputers


Mainframes

Mainframes are computers that are the most bulky types and with the advancement of technology, they have almost become extinct.

Computers are of four types – Supercomputers, Mainframe computers, Minicomputers and Microcomputers.

Mainframe computer systems can be called the predecessor of servers because they could actually support multi users though as efficiently as the servers.

Usually, a main frame would occupy an entire room and could cost over million dollars.

Used for the purpose of research, engineering works, meteorological calculations, graphics and the likes, mainframes today constitutes Unix, Linux, and IBM's z/OS, OS/390, MVS, VM, and VSE.

Mainframe systems were manufactured extensively throughout the 1950s and were marketed by IBM, Control Data, General Electric, NCR, UNIVAC, Honeywell, RC, and Burroughs.


Mainframes

The three important Features of mainframe Computers: Mainframes provide for maximum I/O connectivity as they

accommodate huge disc farms. Mainframes excel in providing maximum I/O band width. Interestingly in spite of all the connected drives connected

to the mainframe system, no data blocking ever happens to mar its efficiency.

Mainframe systems also provide for very good single thread operations.

Most mainframe computers are today’s server computers.


Mainframes

Mainframe Computers


Supercomputers

Supercomputers are one of the many types of modern computing machines which are capable of giving very speedy calculations.

It is because of their high speed processing ability that Supercomputer systems are used in such works as animation graphics, weather forecasting, nuclear research work, petroleum research works, crypt analysis, molecular modeling and the likes.

You must be wondering then what is the difference between a supercomputer and a mainframe computer system?

While Mainframe machines are primarily used for a number of purposes, supercomputers are so designed to serve a singular purpose.

A brief time line of the development of supercomputers has been given as follows:


Supercomputers

1960s: Seymour Cray of Control Data Corporation (CDC) launches

the Supercomputer systems. 1970s:

Cray Research is founded by Seymour Cray after he leaves Control Data Corporation (CDC).

Most supercomputers were meant for running vector processor.

1985-1990: Cray's model of supercomputer takes over the market.

Today, supercomputers are designed by such companies as HP, IBM and of course, Cray Inc.

Supercomputer systems are now becoming almost the same as laptop computers and desktop systems.

Before the 1970s, supercomputers were mostly run on scalar process principle.


Supercomputers

But in order to improve its efficiency a number of new technologies were developed such as: Liquid Cooling Striped Disks (RAID) Parallel File systems Non-uniform memory access (NUMA) Vector Processing

When the hardware of the supercomputers are prepared to serve a special mathematical operation, they are called Special Supercomputers.

Currently there are many such types of supercomputers as the GRAPE for molecular dynamics and astrophysics, Deep Crack for cracking DES cipher, Deep Blue for playing chess, etc.


Supercomputers

Supercomputers


Types of Computers by Purpose General Purpose Computers

A computer designed to perform, or that is capable of performing, in a reasonably efficient manner, the functions required by both scientific and business applications.

Note: A general purpose computer is often understood to be a large system, capable of supporting remote terminal operations, but it may also be a smaller computer, e.g., a desktop workstation.

Special Purpose Computers A computer that is designed to operate on a restricted

class of problems.


Types of Computer by Technology(Classification based on operational

principle)1. Digital Computers2. Analog Computers3. Hybrid Computers

Digital computers Digital Computers are that kind of computing machines

which work on the principle of binary mathematics. Digital computing machines when clubbed with Analog

computers produce Hybrid computers. The digital systems work on the principle of binary

mathematics. In binary mathematics all calculations are represented through “0” and “1”.

You have often heard about the word “Byte”, “Mega Byte”, “Kilo Byte”.

But what is a Byte? A single Byte is a group of 8 numbers or bits represented

through a code series comprising of “0” and “1” . The combination of the digital signal can solve a number of

mathematical operations. It is interesting to note that the fundamentals of mathematics

applied are addition, subtraction, multiplication and division.



Digital computers

But the chief problem is that though it can solve mathematical problems at a tremendous speed, it cannot perform bulk operations simultaneously.

For this purpose, digital systems by themselves cannot give very precise results. Hence, for greater efficiency, the Digital systems do not find much application.

Data Processing In Digital Computers Digital computers function with the help of logic circuits.

A reliable oscillator helps in the proper synchronization of various logic circuits that are responsible for processing data in the digital computers.

In better quality computers, the oscillation rate might even be a billion cycles per second.

Operating at such high speed, it can process more than billions of logic and arithmetic problems.


Digital computers

A digital computer with the help of binary system cannot only perform mathematical problems but also combine the bytes to produce desired graphics, sounds, images and other such commands.


Analog computers Analog Computers and Digital computers are the two kinds of

computers, the combination of which is responsible for the invention of the modern Hybrid computers.

The analog systems carry out arithmetic and logical operations by manipulating and processing data which you input such as the weight, temperature, voltage, power density, etc.

But unlike the digital computer that changes all inputs to binary digits of “1” and “0”, the analog computer does not change inputted data to any such sign language.

The analog computer has become obsolete type of computer these days. It is different from a digital computer as it can perform numerous mathematical operations simultaneously.

The digital computers, however could not operate the more complex operations.

The Analog System is also unique in terms of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation.


Analog computers Mathematical Principles Applied For The Data Processing In

Analog Computers: Logarithm Summation Exponentiation Calculus Multiplication and Division Inversion

The analog computer which is a complex machine is an integration of various mechanical parts which has pipes, valves, levers, gears and several key parts which can be named as follows:- Fixed function generators Operational amplifiers Potentiometers Integrators


Advantages and Disadvantages of Analog Computers

The advantage of an analog computer is that it can simultaneously find solutions to several mathematical problems and that too while being precise unlike the digital computer.

But it is not free of drawbacks. Unlike the digital computer it lacks speed of calculation.

There are other functional problems which mar the efficiency of analog systems.

Of these, the problems of non-linearities, temperature co-efficient, parasitic effects and noise floor are the main problems so to say.


Hybrid Computers

Hybrid computers are, as the name suggests, a combination of both Analog and Digital computers.

The Digital computers which work on the principle of binary digit system of “0” and “1” can give very precise results.

But the problem is that they are too slow and incapable of large scale mathematical operation.

In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control.

Most computers available nowadays are hybrid computers.


Characteristics of Computers

Speed The computer is a very high speed electronic device. The operations on the data inside the computer are

performed through electronic circuits according to the given instructions.

The data and instructions flow along these circuits with high speed that is close to the speed of light.

Computer can perform million of billion of operations on the data in one second.

The computer generates signals during the operation process therefore the speed of computer is usually measure in mega hertz (MHz) or gega hertz (GHz).

It means million cycles units of frequency is hertz per second. Different computers have different speed.


Characteristics of Computers Arithmetical and Logical Operations

A computer can perform arithmetical and logical operations.

In arithmetic operations, it performs the addition, subtraction, multiplication and division on the numeric data.

In logical operation it compares the numerical data as well as alphabetical data.

Accuracy In addition to being very fast, computer is also very

accurate device. It gives accurate output result provided that the correct

input data and set of instructions are given to the computer.

It means that output is totally depended on the given instructions and input data.

If input data is in-correct then the resulting output will be in-correct, i.e., Garbage In, Garbage Out (GIGO).

In computer terminology it is known as garbage-in garbage-out.


Characteristics of Computers Reliability

The electronic components in modern computer have very low failure rate.

The modern computer can perform very complicated calculations without creating any problem and produces consistent (reliable) results. In general, computers are very reliable.

Many personal computers have never needed a service call. Communications are also very reliable and generally available whenever needed.

Storage A computer has internal storage (memory) as well as external or

secondary storage. In secondary storage, a large amount of data and programs (set

of instructions) can be stored for future use. The stored data and programs are available any time for

processing. Similarly information downloaded from the internet can be saved

on the storage media.



Retrieving data and programs The data and program stored on the storage media can be

retrieved very quickly for further processing. It is also very important feature of a computer.

Automation A computer can automatically perform operations without

interfering the user during the operations. It controls automatically different devices attached with

the computer. It executes automatically the program instructions one by

one.



Versatility Versatile means flexible. Modern computer can perform different kind of tasks one

by one of simultaneously. It is the most important feature of computer. At one moment your are playing game on computer, the

next moment you are composing and sending emails etc. In colleges and universities computers are use to deliver

lectures to the students. The talent of computer is dependent on the software.



Communications Today computer is mostly used to exchange messages or

data through computer networks all over the world. For example the information can be received or send

through the internet with the help of computer. It is most important feature of the modern information

technology. Diligence

A computer can continually work for hours without creating any error.

It does not get tired while working after hours of work it performs the operations with the same accuracy as well as speed as the first one.


Characteristics of Computers No Feelings

Computer is an electronic machine. It has no feelings. It detects objects on the basis of instructions given to it.

Based on our feelings, taste, knowledge and experience: we can make certain decisions and judgments in our daily life.

On the other hand, computer can not make such judgments on their own.

Their judgments are totally based on instructions given to them.

Consistency People often have difficulty to repeat their instructions

again and again. For example, a lecturer feels difficulty to repeat a same

lecture in a class room again and again. Computer can repeat actions consistently (again and

again) without loosing its concentration:



To run a spell checker (built into a word processor) for checking spellings in a document.

To play multimedia animations for training purposes. To deliver a lecture through computer in a class room etc.

A computer will carry out the activity with the same way every time.

You can listen a lecture or perform any action again and again.

Precision Computers are not only fast and consistent but they also

perform operations very accurately and precisely. For example, in manual calculations and rounding fractional

values (That is value with decimal point can change the actual result).

In computer, however, you can keep the accuracy and precision up to the level you desire.

The length calculations remain always accurate.


Limitations of Computers

Programmed by human: Though computer is programmed to work efficiently, fast

and accurately but it is programmed by human beings to do so.

Without a program, computer is nothing. A program is a set of instructions. Computer only follows these instructions. If the instructions are not accurate the working of

computer will not accurate. Thinking:

The computer can not think itself. The concept of artificial intelligence shows that the

computer can think. But still this concept is dependent on set of instructions

provided by the human beings.


Limitations of Computers Self Care:

A Computer can not care itself like a human. A computer is dependent still to human beings for this purpose.

Retrieval of memory: A computer can retrieve data very fast but this technique is

linear. A human being's mind does not follow this rule. A human mind can think randomly which a computer machine

can not. Feelings:

One of the main limits in the computer is of feeling. A computer can not feel about some like a human. A computer can not meet human in respect of relations. Human can feel, think and caring but a computer machine itself

can not. A computer can not take place of human because computer is

always dependent of human.


Application of Computers Word Processing

Word Processing software automatically corrects spelling and grammar mistakes.

If the content of a document repeats you don’t have to type it each time.

You can use the copy and paste features. You can printout documents and make several copies. It is easier to read a word-processed document than a

handwritten one. You can add images to your document.


Application of Computers

Internet It is a network of almost all the computers in the world. You can browse through much more information than you

could do in a library. That is because computers can store enormous amounts

of information. You also have very fast and convenient access to

information. Through E-Mail you can communicate with a person sitting

thousands of miles away in seconds. There is chat software that enables one to chat with

another person on a real-time basis. Video conferencing tools are becoming readily available to

the common man.



Digital video or audio composition Audio or video composition and editing have been made

much easier by computers. It no longer costs thousands of dollars of equipment to

compose music or make a film. Graphics engineers can use computers to generate short

or full-length films or even to create three-dimensional models.

Anybody owning a computer can now enter the field of media production.

Special effects in science fiction and action movies are created using computers.


Application of Computers Desktop publishing

With desktop publishing, you can create page layouts for entire books on your personal computer.

Computers in Medicine You can diagnose diseases. You can learn the cures. Software is used in magnetic resonance imaging to

examine the internal organs of the human body. Software is used for performing surgery. Computers are used to store patient data. Telemedicine is one of computer applications in health.

Mathematical Calculations Thanks to computers, which have computing speeds of

over a million calculations per second we can perform the biggest of mathematical calculations.



Banks All financial transactions are done by computer software. They provide security, speed and convenience.

Travel One can book air tickets or railway tickets and make hotel

reservations online. Telecommunications

Software is widely used here. Also all mobile phones have software embedded in them.

Defense There is software embedded in almost every weapon. Software is used for controlling the flight and targeting in

ballistic missiles. Software is used to control access to atomic bombs.


Application of Computers E-Learning

Instead of a book it is easier to learn from an E-learning software.

Gambling You can gamble online instead of going to a casino.

Examinations You can give online exams and get instant results. You can check your examination results online.

Computers in Business Shops and supermarkets use software, which calculate the bills. Taxes can be calculated and paid online. Accounting is done using computers. One can predict future trends of business using artificial

intelligence software. Software is used in major stock markets. One can do trading online. There are fully automated factories running on software.


Application of Computers Certificates

Different types of certificates can be generated. It is very easy to create and change layouts.

ATM machines The computer software authenticates the user and

dispenses cash. Marriage

There are matrimonial sites through which one can search for a suitable groom or bride.

News There are many websites through which you can read the

latest or old news. Classmates

There are many alumni websites through which you can regain contact with your classmates.



Robotics Robots are controlled by software.

Washing Machines They operate using software.

Microwave Oven They are operated by software.

Planning and Scheduling Software can be used to store contact information,

generating plans, scheduling appointments and deadlines. Plagiarism

Software can examine content for plagiarism. Greeting Cards

You can send and receive greetings pertaining to different occasions.



Sports Software is used for making umpiring decisions. There are simulation software using which a sportsperson

can practice his skills. Computers are also to identify flaws in technique.

Airplanes Pilots train on software, which simulates flying.

Weather analysis Supercomputers are used to analyze and predict weather.


The Advantage of Humans over Computers

“Humans are indispensable” Humans have the unique quality of thinking.

People are creative Computers are only consistent

People are motivated and take initiatives Humans are more flexible in their thinking. People are mobile than computers. People are biological whereas computers are artificial.


Components of a Computer

Computer is programmable (instructable) electronic device. Computer system ahs two main components:

The hardware components of a computer system are the electronic and mechanical parts.

The software components of a computer system are the intangible parts: the data and the computer programs.


Hardware Component of the Computers System

Hardware: Is the visible, tangible and physical component of the

computer system. It is the assemblage of metallic and plastic components

that make up the computer. The hardware carries out the activities of capturing,

processing, storing and communicating data and information.

The computer hardware has the following main componenets.

Input Devices Processing Devices Storage devices, and Output devices

In addition, the hardware components comprises of power supplies, Cables, Connectors and ports, expansion cards and expansion slots, and the motherboard.


1. Input Devices Any hardware device that sends data to the computer. without any input devices, a computer would only be a

display device and not allow users to interact with it, much like a TV.

Below is a full listing of all the different types of computer input devices found on a computer. Keyboard Mouse (pointing device) Trackball Scanner Digital camera MICR (Magnetic Ink Character Recognition) OCR (Optical Character Recognition) OMR (Optical Mark Recognition)


Input Devices

Barcode reader Microphone Touch Screen Light Pen Joystick Digitizing Tables Webcam Gamepad MIDI keyboard


The Keyboard

Keyboard is one of the main input devices used on a computer A PC's keyboard looks very similar to the keyboards of electric

typewriters, with some additional keys. Today most users use the QWERTY style keyboards Keyboard has keys with a variety of functions.

Escape (Esc) key - Equivalent to clicking the Cancel button. Tab Key - This key can be used to move forward through

options in a dialog box. Caps Lock Key - Locks the keyboard in "Capitals" mode (only

applies to Alpha keys). Shift Keys (Left and Right) - The obvious use of this key is to

allow selection of capital letters when depressing the alphabet characters, or selecting the characters above other non-alpha keys.


The Keyboard

Control (Ctrl) Keys (Left and Right) - Depressing the Ctrl key while clicking allows multiple selections. Holding the Ctrl key down and pressing other key combinations will initiate quite a few actions.

Alternate (Alt) Keys (Left and Right) - Located on either side of the space bar. Holding the Alt key down and pressing another key will initiate various actions.

Function Keys (F1 to F12) - Windows Key (Left and Right) - On either side of the

spacebar, outside the Alt key, is a key with the Windows logo. Holding the Windows key down and pressing another key will initiate quite a few actions.

Spacebar Key - Insert a space between words.


The Keyboard Application Key – Key with cursor symbol used as right-clicking Enter Key - Creates a new Paragraph <p> () or what is referred

to as a Hard Return. Backspace Key - While working with text, use this key to delete

characters to the left of the insertion point. Home Row Keys – Keys where typing hands’ fingers rest Alphanumeric Keys – Keys with uppercase and lowercase

letter, numbers, punctuation marks, arithmetic operators, equality operators, logic operators and other special characters.

Arrow Keys – used to navigate up, down, left and right Insert Key – Used to insert commands alone or in combination

with another keys Delete Key - While working with text, use this key to delete

characters to the right of the insertion point. This key can also be used to delete selected files. If you use the keyboard combination Shift + Delete the item is permanently deleted, bypassing the Recycle Bin.

Home Key - Depress and hold the Ctrl key as you select Home to go to the first line of a document.


The Keyboard

End Key - Depress and hold the Ctrl key as you select End to go to the last line of a document.

Page Up Key - In a browser window use the Page Up key to move up one full screen on a web page.

Page Down Key - In a browser window use the Page Down key to move down one full screen on a web page.

PrtScn/SysRq Key – Used to capture and print active window screen

Scroll Lock Key - The scroll lock key is intended to temporarily stop the scrolling of text or halt the operation of a program.

Numeric Keypad - If you want to use the numeric keypad on the right end of the keyboard to display numbers, the Num Lock key must be selected (usually a light above the Num Lock will indicate that it is on). If you want to use the keypad to navigate within a document, turn off Num Lock by pressing the key (the light will go off).


The Keyboard

New Model Multimedia Computer Keyboard


The Mouse

Mouse: Is a device that controls the movement of the cursor or

pointer on a display screen. A mouse is a small object you can roll along a hard, flat

surface. Its name is derived from its shape, which looks a bit like a

mouse, its connecting wire that one can imagine to be the mouse's tail, and the fact that one must make it scurry along a surface.

As you move the mouse, the pointer on the display screen moves in the same direction.

Mice (plural form of mouse) contain at least one button and sometimes as many as three, which have different functions depending on what program is running.

Some newer mice also include a scroll wheel for scrolling through long documents.


The Mouse

Invented by Douglas Engelbart of Stanford Research Center in 1963, and pioneered by Xerox in the 1970s, the mouse is one of the great breakthroughs in computer ergonomics because it frees the user to a large extent from using the keyboard.

In particular, the mouse is important for graphical user interfaces because you can simply point to options and objects and click a mouse button.

Such applications are often called point-and-click programs.

The mouse is also useful for graphics programs that allow you to draw pictures by using the mouse like a pen, pencil, or paintbrush.


The Mouse

There are three basic types of mice:mechanical

• Has a rubber or metal ball on its underside that can roll in all directions.

• Mechanical sensors within the mouse detect the direction the ball is rolling and move the screen pointer accordingly.

Optomechanical• Same as a mechanical mouse, but uses optical sensors to detect

motion of the ball. optical:

• Uses a laser to detect the mouse's movement.• You must move the mouse along a special mat with a grid so

that the optical mechanism has a frame of reference.• Optical mice have no mechanical moving parts.• They respond more quickly and precisely than mechanical and

optomechanical mice, but they are also more expensive.


The Mouse

Mice connect to PCs in one of several ways:Serial mice

• connect directly to an RS-232C serial port or a PS/2 port.• This is the simplest type of connection.

PS/2 mice• connect to a PS/2 port.

USB mice. Cordless mice

Aren't physically connected at all. Instead they rely on infrared or radio waves to communicate

with the computer. Cordless mice are more expensive than both serial and bus

mice, but they do eliminate the cord, which can sometimes get in the way.


The Mouse

A mouse has three buttons. Left Button

Used for left single and double clicking It can also used for dragging and dropping if the mouse is set

as primary button Middle Button

Used for scrolling Right button

Used for right single and double clicking It can also used for dragging and dropping if the mouse is set

as primary button


The Mouse

Left Button

Mid

dle

Butto

n

Righ

t Bu

tton

Optical Mouse


The Trackball

Trackball is another pointing device used to input data into the computer system

Essentially, a trackball is a mouse lying on its back. To move the pointer (cursor), you rotate the ball with your

thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which

you use just like mouse buttons.

The Trackball


The Scanner Scanner is an input device that can read text or illustrations

printed on paper and translate the information into a form that the computer can use.

Scanner is visual information or data processing input device. A scanner takes a picture placed on the scanner screen and

digitizes the information in order to present it on the computer screen for manipulation.

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display.

Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color.

Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display.

Scanners usually come with software, such as Adobe's Photoshop product, that lets you resize and otherwise modify a captured image.


The Scanner

Flatbed Scanner

Sheet-fed

Scanner

Flatbed Scanner

Flatbed Scanner


The Digital camera

Digital Camera is a camera that stores images digitally rather than recording them on film.

Once a picture has been taken, it can be downloaded to a computer system, and then manipulated with a graphics program and printed.

Unlike film photographs, which have an almost infinite resolution, digital photos are limited by the amount of memory in the camera, the optical resolution of the digitizing mechanism, and, finally, by the resolution of the final output device.

Even the best digital cameras connected to the best printers cannot produce film-quality photos.

However, if the final output device is a laser printer, it doesn't really matter whether you take a real photo and then scan it, or take a digital photo.

In both cases, the image must eventually be reduced to the resolution of the printer.


The Digital camera The big advantage of digital cameras is that making photos is

both inexpensive and fast because there is no film processing.

Interestingly, one of the biggest boosters of digital photography is Kodak, the largest producer of film.

Kodak developed the Kodak PhotoCD format, which has become the de facto standard for storing digital photographs.

Most digital cameras use CCDs to capture images, though some of the newer less expensive cameras use CMOS chips instead.

Digital cameras can be still cameras, video cameras and webcams.

Digital Camera


The Magnetic Ink Character Recognition (MICR)

In computing, a technique that enables special characters printed in magnetic ink to be read and input rapidly to a computer.

MICR is used extensively in banking because magnetic-ink characters can be machine-read with much greater accuracy than human reading or other optical character recognition (OCR) systems, and are therefore ideal for marking and identifying the account and sort code numbers on cheques.

MICR allows the computer to recognize characters printed using magnetic ink.

Magnetic Ink Character Recognition is a character recognition system that uses special ink and characters.

When a document that contains this ink needs to be read, it passes through a machine, which magnetizes the ink and then translates the magnetic information into characters.

MICR technology is used by banks. Numbers and characters found on the bottom of checks (usually

containing the check number, sort number, and account number) are printed using Magnetic Ink.

To print Magnetic Ink need, you need a laser printer that accepts MICR toner.

MICR provides a secure, high-speed method of scanning and processing information.

The Magnetic Ink Character Recognition (MICR)


Magnetic Ink Character Recognition, or MICR, is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques.

The technology allows computers to read information (such as account numbers) off of printed documents.

Unlike barcodes or similar technologies, however, MICR codes can be easily read by humans.

MICR characters are printed in special typefaces with a magnetic ink or toner, usually containing iron oxide. As a machine decodes the MICR text, it first magnetizes the characters in the plane of the paper. Then the characters are passed over a MICR read head, a device similar to the playback head of a tape recorder. As each character passes over the head it produces a unique waveform that can be easily identified by the system.

The use of magnetic printing allows the characters to be read reliably even if they have been overprinted or obscured by other marks, such as cancellation stamps. The error rate for the magnetic scanning of a typical check is smaller than with optical character recognition systems. For well printed MICR documents, the "can't read" rate is usually less than 1% while the substitution rate (misread rate) is in the order of 1 per 100,000 characters.

MICR

MICR


The Optical Character Recognition (OCR)

OCR reads text from paper and translate the image into a form that the computer can manipulate, i.e., into ASCII, EBCDIC, UNICODE and so on Schemes).

All OCR systems include an optical scanner for reading text, and sophisticated software for analyzing images.

The potential of OCR systems is enormous because they enable users to harness the power of computers to access printed documents.

OCR (optical character recognition) is the recognition of printed or written text characters by a computer.

This involves photoscanning of the text character-by-character, analysis of the scanned-in image, and then translation of the character image into character codes, such as ASCII, commonly used in data processing.

In OCR processing, the scanned-in image or bitmap is analyzed for light and dark areas in order to identify each alphabetic letter or numeric digit.

When a character is recognized, it is converted into an ASCII code. Special circuit boards and computer chips designed expressly for OCR are used to speed up the recognition process.

OCR is being used by libraries to digitize and preserve their holdings. OCR is also used to process checks and credit card slips and sort the mail.

Billions of magazines and letters are sorted every day by OCR machines, considerably speeding up mail delivery.


The Optical Character Recognition (OCR)

OCR

OCROCR

OCR Stands for "Optical Character Recognition." This technology is what allows you to scan that paper you lost on your hard drive, but fortunately printed out, back into your computer. When a page of text

is scanned into a computer without OCR software, all the computer sees is a bunch graphical bits, or an image. In other words, it has no idea that there is text on the page, much less what the text says.

However, an OCR program can convert the characters on the page into a text document that can be read by a word processing program. More advanced OCR programs can even keep the formatting of the document in the conversion.


The Optical Mark Recognition (OMR)OMR is also

called mark sensing.

It is a technology where an OMR device senses the presence or absence of a mark, such as a pencil mark.

OMR is used in tests such as aptitude test

OMR System

OMR System


The Barcode Reader

A barcode reader (or barcode scanner) is a computer peripheral for reading barcodes printed on various surfaces.

Like a flatbed scanner, it generally consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones.

Additionally, nearly all barcode readers currently produced contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output port.

However, in contrast to a flatbed scanner, a typical barcode scanner's optical components do not move as the barcode is one-dimensional and can be scanned all at once.

Many different types of barcode scanners are available. They can be distinguished as follows:


The Barcode Reader A barcode reader (or barcode scanner) is a computer

peripheral for reading barcodes printed on various surfaces. Like a flatbed scanner, it generally consists of a light source,

a lens and a photo conductor translating optical impulses into electrical ones.

Additionally, nearly all barcode readers currently produced contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output port.

However, in contrast to a flatbed scanner, a typical barcode scanner's optical components do not move as the barcode is one-dimensional and can be scanned all at once.

Barcode reader is photoelectric scanners that read the bar codes, or vertical zebra strips marks, printed on product containers.

Barcode readers are popularily used in supermarkets and bookshops, etc.

The Barcode Reader Many different types of barcode scanners are available. They can be distinguished as follows:

By light source: LED scanners

• also referred to as CCD scanners -- even if the CCD is in fact the photo conductor

laser scanners • much more expensive than LED scanners but are capable of scanning

barcodes at a distance of up to 25cm (~10")

By housing: handheld scanner

with a handle and typically a trigger button for switching on the light source

pen scanners (or wand scanners) a pen-shaped scanner that is swiped across a barcode

stationary scanners wall- or table-mounted scanners that the barcode is passed under or

beside. These are commonly found at the checkout counters of supermarkets and

other retailers.



The Barcode Reader Most barcode readers use a PS/2 wedge cable for output:

This cable is connected to the host computer's PS/2 keyboard port with its first end, to the keyboard with its second, and to the barcode reader with its third end.

The barcode characters are then received by the host computer as if they came from its keyboard.

Many readers can be also equipped with an RS-232 output port so that the decoded characters arrive at the computer via one of its RS-232 connectors.

However, USB-based barcode readers are quite rare to date.

Today's barcode scanners handle all popular barcode symbologies like EAN/UPC, Code 39 or Code 128.

Advanced models also understand rather rarely used symbologies. A special type of barcode reader is the matrix-code reader for decoding two-dimensional codes such as PDF417.


The Barcode Reader

Barcode

B

a

r

c

o

d

e

R

e

a

d

e

r

s


The Microphone

Microphone is speech input device. Microphone is used to gather sound information to the

computer when the computer is a multimedia system. Microphone converts sound into signals that can then be

stored, manipulated, and played back by the computer. A microphone, sometimes called a "mic" (pronounced

"mike"), is a device that converts sound into an electrical signal.

Microphones are used in many applications such as telephones, tape recorders, hearing aids and in radio and television broadcasting.

The invention of a practical microphone was crucial to the early development of the telephone system.

Emile Berliner invented the first microphone on March 4, 1877, but the first useful microphone was invented by Alexander Graham Bell.

Many early developments in microphone design took place in Bell Laboratories.


The Microphone In all microphones, sound waves (sound pressure) are

translated into mechanical vibrations in a thin, flexible diaphragm.

These sound vibrations are then converted by various methods into an electrical signal which varies in voltage amplitude and frequency in an analog of the original sound.

For this reason, a microphone is an acoustic wave to voltage modulation transducer.

The following are the most commonly used types of microphones. capacitor microphone, also known as a condenser

microphone foil electret microphone dynamic microphone ribbon microphones carbon microphone piezo microphone

Microphone can also be categorized as wired (corded) and wireless or cordless.


The Microphone

Different types of

Microphones

Cordless Microphone

Corded w

ith st

anding

Microphone

Corded Microphone

Vast Range of Microphones


The Touch Screen A display screen that is sensitive to the touch of a finger or

stylus. Widely used on ATM machines, retail point-of-sale terminals, car

navigation systems, medical monitors and industrial control panels, the touch screen became wildly popular on handhelds after Apple introduced the iPhone in 2007.

Touch screens offer several advantages, the primary one being the infinite ways the user interface can be designed and changed compared to a fixed set of physical buttons.

If there is no hardware keyboard on the unit, a "soft" keyboard can be displayed on screen whenever text must be typed in.

Touch screens are also able to accept hand printing, handwriting, graphics and finger movements.

Touch screens can also be made resistant to harsh environments, compared to ordinary computer monitors.

All touch screens "digitize" the point of contact on screen into an X-Y coordinate. They fall into two major categories: active digitizer and passive touch screen.


The Touch Screen

Touch Screen Technologies


The Light Pen

A lightpen is a device similar to a touch screen, but is facilitated by use of a special light sensitive pen instead of the finger.

The advantage of using a pen is more accurate screen input than possible with a touch screen, also a light pen needs no special screen but can work with any CRT-based monitor.

However, light pens cannot work with LCD screens, projectors etc.

A lightpen is fairly simple to implement, but is rather dependent on the video hardware which drives the display.

This is one reason it fell out of use - it would require a special port on every video display card, whereas the mouse can be implemented solely in software.

In addition, ergonomic factors favour the mouse - it can be tiring to operate a computer using a lightpen over long periods.

The lightpen works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot.


The Light Pen

By noting exactly where the scanning has reached at that moment resolves the X,Y position of the pen.

This is usually achieved by making the lightpen cause an interrupt, at which point the scan position can be read off from a special register, or computed from a counter or timer.

The pen position is updated on every refresh of the screen. Lightpens operate best with relatively slow-scanning displays of low resolution, such as a television screen.

The light pen became moderately popular during the early 1980s It was notable for its use in the Fairlight CMI, and the BBC Micro.

However the lightpen's usage greatly declined later in the decade with the adoption of mouse-based WIMP interfaces as well as changes in monitor technology.

The first light pen was used around 1957 on the Lincoln TX-0 computer at the MIT Lincoln Laboratory.


The Light Pen

Light pens


The Joystick

A joystick is an input device commonly used to control video games. Joysticks consist of a base and a stick that can be moved in any direction.

The stick can be moved slowly or quickly and in different amounts.

Some joysticks have sticks that can also be rotated to the left or right.

Because of the flexible movements a joystick allows, it can provide much greater control than the keys on a keyboar

Joysticks typically include several buttons as well. Most joysticks have at least one button on the top of the stick and another button in the front of the stick for the trigger.

Many joysticks also include other buttons on the base that can be pressed using the hand that is not guiding the stick.

Joysticks typically connect to your computer using a basic USB or serial port connection and often come with software that allows you to assign the function of each button.


The Joystick

Since joysticks emulate the controls of planes and other aircraft, they are best suited for flight simulators and flying action games.

However, some gamers like to use joysticks for other types of video games, such as first-person shooters and fighting games.

Others prefer using the basic keyboard and mouse, with which they are already accustomed to.

Joysticks


The Digitizing Tablets

A graphics tablet (or digitizing tablet) is a computer peripheral device that allows for a relatively simple method of inputing hand-drawn graphics or art into a computer in real time.

They typically consist of a large flat surface for drawing on, and an attached "stylus" for drawing on the surface, originally as a part of the electronics, but later simply to provide an accurate but smooth "point".

Early graphics tablets, known as spark tablets, used a stylus that generated clicks with a spark plug.

The clicks were then triangulated by a series of microphones to locate the pen in space.

Needless to say this was a complex and expensive system, one that was also rather sensitive to outside noise.


The Digitizing Tablets

Digitizing Tablets


The Webcam The term webcam is a combination of "Web" and "video camera." The purpose of a webcam is, not surprisingly, to broadcast video on the Web. Webcams are typically small cameras that either attach to a user's monitor

or sit on a desk. Most webcams connect to the computer via USB, though some use a Firewire

connection. Webcams typically come with software that allows the user to record video or

stream the video on the Web. If the user has a website that supports streaming video, other users can

watch the video stream from their Web browsers. Webcam is a camera that is attached to someone's computer. This camera takes pictures every few minutes and updates those pictures to

a Web page where everyone can watch. Some Webcams are set up in people's houses and allow you to watch them

as they go about their day to day business. Others are set up outside and allow you to watch the scenery of a particular

area. They are also called Web cam, or web camera. Most laptops nowadays come with built-in webcam.


The Webcam

Webcams


The Gamepad A gamepad (also called joypad or control pad), is a type of

game controller held in the hand, where the digits (especially thumbs) are used to provide input.

Gamepads generally feature a set of action buttons handled with the right thumb and a direction controller handled with the left.

The direction controller has traditionally been a four-way digital cross (also named a joypad, or alternatively a D-pad), but most modern controllers additionally (or as a substitute) feature an analog stick.

The most common game controller devices are: Gamepad Paddle Trackball Joystick Arcade style Joystick


The Gamepad

Throttle quadrant Steering wheel Yoke Pedals Keyboard and mouse Gaming keypads and programmable PC controllers Touch screen Motion sensing Light gun Others


The Gameoad

Gamepads


MIDI Keyboard

A MIDI keyboard is a piano-style digital keyboard device used for sending Musical Instrument Digital Interface (MIDI) signals or commands to other devices connected to the same interface as the keyboard.

The basic MIDI keyboard does not produce sound. Instead, MIDI information is sent to an electronic module

capable of reproducing an array of digital sounds or samples that resemble traditional analog musical instruments.

These samples are also referred to as voices. An encoding scheme is used to map a MIDI value to a specific

instrument sample. Also, other sound parameters such as note volume and

attack are included in the MIDI scheme. The keyboard merely acts as a MIDI controller of sound

modules and other MIDI devices, including DAW software.


MIDI Keyboard

MIDI keyboards are a very common feature of a recording studio, and any DAW setup.

Most include a transpose function and the ability to set different octaves.

Many MIDI keyboards have pitch bend and modulation wheels. Some also have extra sets of assignable rotary knobs and/or buttons

for sending custom MIDI messages to the synthesizer, sampler or DAW software.

Other features that some MIDI keyboards might include are: Input for foot switch (usually used as a sustain pedal) Input for a foot expression controller Semi-weighted or fully weighted keys Capability of sending after touch Direct USB connection for use with computers

MIDI keyboards come in a range of sizes, from 25 keys (two octaves) to full 88-key length.

MIDI keyboards with fewer than 61 keys tend not to have weighted keys.


MIDI Keyboard

MIDI Keyboard


2. Processing devices The sole processing device in the computer system is CPU. CPU stands for Central Processing unit. CPU has four main components.

CUControl Unit, this sequences, controls and times the other

functions of the CPU. ALU

Arithmetic Logic Unit, this carries out simple mathematical equations on the binary data stored inside the data registers.

Registers These are temporary memory locations which hold binary data and

store the results of ALU calculations. There are also memory address registers which, as the name

suggests, hold data concerning where in the memory certain instructions and data is held.

BUS (FBS – Front Bus Side) This carries data between the memory and registers.


2. Processing devices CPU is also called processor or microprocessor. The processor (often called the CPU) is the brain of your PC

and is where the majority of the work is performed. As its name suggests a processor processes something, that

something is data, this data is made up of 0's and 1's (zeroes and ones).

Central Processing Unit, Computer CPU, is the component installed in your motherboard socket.

The CPU executes and interprets programs, and processes data.

Like a calculator it reads the information you give, interprets it, executes the equation, then writes back the result.

This gives you the big picture. CPU comes in 2 brands, AMD and Intel. Both build equally good CPUs, with their own features. I think, Intel tend to be more stable and AMD faster for

games.


2. Processing devices


Software Component of the Computers System

mishqen college department of ict this module covers: introducing information and communication...

Documents

computer systems

personal computer ict

system software ict

computer hardware application

standards computer hazards

eos ict ita s01

basic computer operations

computer history museum