The Hardware Parts

The Hardware Parts
What we will describe here is a desktop personal computer complete with the ability to connect you to the Internet through your telephone line and play mu8sic and video for your entertainment. Virtually all personal computer (or PC) available in the market will fall in this category, with some additional or omissions.

Most PCs have a Central Processing Unit or CPU as their brain, a monitor as their output device and a keyboard plus a mouse as their input devices, In addition, the computer will have permanent memory known as Read Only Memory or ROM on fixed or hard disk drives and temporary memory as silicon chips called Random Access Memory or RAM. The permanent memory includes your computer’s software programmers as well as data that you wish to retain for future use. The permanent memory is not lost when you switch off your computer. On the other hand, temporary memory is used by the computer’s CPU while the computer’s temporary memory is lots when you shut your computer down.

These hardware items from the bare essentials of the physical parts of a working PC. In your PC, these there may be many additional hardware items called peripherals such as CD-ROM f\drive or a printer. Let us now discuss the hardware items one by one by one.

The computer is box-shared. It may be flat for use on the desktop, or a vertical tower for placing below the dust. It consists of:

1.A Processor,
such as Intel’s Pentium or MAD Catholic. These processors range from 100 MHz to the latest 2,200 MHz clock speeds. This is not the final speed, however. Processors continue to become faster relentlessly. According to Moor’s law, the processor speed doubles every 18 months.

2.A Motherboard,
which functions as an organizer for the hardware parts that must work in unison with the processor. For example, the RAM, the ports for connecting the keyboards and the mouse, the video cards for connecting the keyboards and mouse, the video card that controls the monitor’s display and many such components are mounted on or plugged into the motherboard.

These components are electrically connected to each other through a bus or trucking of copper conductors etched on the motherboard. The processor speed is controlled by a quartz crystal clock that provides the pluses required to synchronizes the working component are electrically connected to etched on the motherboard. The processor speed is controlled by a quart.

3.One or more Hard Disk (s)
whose magnetic memory is used to save the data and programmer files. Hard Disks are fixed inside inside the computer reads as soon as it is switched on. The ROM program, called the bootstrap programmer provides the start-up instructions. After ROM programmer, called the bootstrap programmer provides the start-up instructions. After the bootstrap programmer is loaded, it instructs the computer to load the operating system such as Windows and memory.

4.Some PCs have a Graphic Ace;aerator Card. This card is usually used for video games and for graphics rendering, which require a great deal of fast calculations to produce rapidly changing and complex pictures and graphics on the monitor;s screen.

5.To produce the stereophonic sound requi8red for m,multimedia games and movies, the computer may have a separate sound card or, the sound capability may be built into the motherboard itself.

Characteristics of computers- Features of Computers

Characteristics of computers- Features of Computers



The increasing popularity of computers has proved that it is a very powerful and useful tool. The power and usefulness this popular tool is mainly due to its following characteristics:

1.Automatic:

A machine is said to be automatic, if it works by itself without itself without human interventions. Computer is automatic machines because once on a job, they carry on, until the job is finished, normally without any human assistance. However, computers being machines cannot start themselves. They cannot go out and find their own problems and solutions. They have to be instructed. That is, a computer works from a program of coded instructions, which specify exactly how a particular job is to be done. Some of the other characteristic of computers, such as speed and accuracy, are due to the fact they are automatic, and work on a problem without any human intervention.

2.Speed:

A computer is very fast device. It can perform in a few seconds, the amount of work that a human being can do in an entire year- if he worked day and night and did nothing else. To put it in a deference manner, a computer does in one minute what would take a man his entire lifeline.

3.Accuracy:

In additions to being very fast, computers are very accurate. The accuracy of computer is consistent high, and the degree of accuracy of particular computer depends upon its design. However, these are mainly due to performed with the same accuracy.

4.Diligence:

Unlike human beings, a computer is free from monotony, trendless and lack of concentration. It can continuously work for hours, without creating much error and without grumbling, hence, computers score over human beings in doing routine type of jobs, which require great accuracy. If ten million calculations have to be performed, a computer will perform the ten millionth calculations with exactly the same accuracy and speed as the first one.

5.Versatility:

Versatility is one of the most wonderful things about the computer. Once moment, it is preparing the results of examinations, the net moment, it is busy preparing electronic bills, and between, it may be helping an offices secretary to trace a important letter in seconds. All that is required to change its talent is to slip in a new program into it. Briefly a computer is capable of performing almost many tasks, if the task can be reduced to a series of logical steps.

6.Power of Remembering: As a human being acquires new knowledge, the brain subconsciously selects what it feels to be important and worth retaining in memory, and relegates unimportant details what it feels. This is not case with computers. A computer can store and recall any amount of information because of its secondary storage (a type of detachable memory) capability. Every piece of information can be retained as long as desired by the user, and can be can be recalled. As and when it was fed to the computer several years, the information recalled would be as accurate as on the day when it was fed to the computer. A computer. A computer forgets or looses certain information only when it is asked to do so. Hence, it is entirely up to the user, to make a computer retain or forget particular information.

7.No Feelings:

Computers are devoid of emotions. They have no feelings and no instincts because they are machines. Although men have succeeded in building a memory for the computer, but no computer possesses the equivalent of a human heart and soul. Based on your on our day-to-day life. However, computer to then in the form of programs that are written by us.







Characteristics of computers- Features of Computers

Introduction

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Computer ! an amazing machine! We are living in the computer age today and most of our day activities cannot be a accomplished without using computers. sometimes knowingly and sometimes unknowingly we use computers. Whether we have to withdraw money from the ATM(Automated Teller Machines, retranslated as Any Time Money), publish a newsletter, drive a motorbike, design a building or even a new dress, go to a grocery shop and by from cookies to types for our car – all involve computer in one way or the other.
We are breathing in the computer age and gradually computer has becomes such are breathing in the computer age and gradually computer has become such a dire necessity of life that it is difficult life without it.
Computer is affecting every sphere of our life. Be it government, business, education, legal practice, entertainment, defense or home – computer has becomes an indispensable and multipurpose tool.

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Computer Definition

For most of the people, computer is a machine used for calculations or computation, but actually, it is much more than that. Precisely, “Computer is a device for performing arithmetic and logical operations”, or “Computer is a device or flexible machine to process data and convert it into information”.
Now, in the above two definitions, three words are tricky that need some explanations. Let us start with logical operation-these are the type of operation in which decision(s) is/are involved. Data is simply raw fact or figure collected whereas the information is what one gets after processing the data. Information is always useful and meaningful for the user. Let us consider and example in which marks of various subjects are collected for a particular group of students. Now, these marks independently(data) are of no use as such for the class teacher, but once she he adds the marks of all the students and calculates their respective percentages, this becomes information and it serves her/him in finding out the answer for the queries like Who has 1st in the class? Or How many people have got distinctions in the class? What is the overall performance of the class? “A program is a set of instructions telling the computer what to do.”

Need for Computer Literacy

Computers have shaken up the world. They have made us dependent upon them. We expect them to be present at every place: be it the reservation counter, the microwave cooking or even driving a car. Now that computers have moved in our society so rapidly, one needs, at least the basic computer skills to pursue one’s career goals and function effectively and effectively. We can say that computer literacy is the need of today and voice of tomorrow to survive on the fast changing world of computers.

For most of the people computer literacy is restricted to using the keyboard for typing a document or making use of it for the calculations. But this is not enough. One must know the fundamental concept about what computers constitute of and how the they work. Take an example, you drive a motorbike and you take it for the servicing. There is one way that you tell the service boy to service the motorbike and I will collect it in the evening. The another way could be that you tell him that, apart from servicing, please change the engine oil and clean the carburetor too. This way the service man would be more careful while doing the job of your motorbike and you too will be able to solve at least some of the small problems when the machine is not available. The lack of knowledge can cause mistakes while using the computer also. Sometimes this lack of knowledge can cause mistakes while using the computer also. Lack of knowledge can cause mistakes while using the computer also. Sometimes this lack of knowledge cause some fear in the people. This is termed as CYBERPHOBIA

Characteristics of Computers

Speed: A computer is a very fast and accurate device. It can process thousands of instructions within a few seconds for which a human being can take several days or months.

Accuracy: Degree of accuracy of the computer is very high. Errors can occur in computerized system also but most of them occur due to human mistakes rather than technical problems is the computer.

Versatility: We can perform many different tasks on the computer. One moment it might be busy in calculating the statistical data of a business organization for annual performance evaluation and at next moment it is capable of working on inventory control.

Permanent Memory: We can store very large amount of information in the secondary storage devices. This information stays with the computer for further use where as humans tend to forget things.

Diligence: Computer is free from problems like exhaustion, lack of concentration, confusion, etc., unlike human beings.
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Basic Anatomy of Computers

Broadly computer can be said to be made up of hardware and software. The computer hardware(actual machine) is defined in such a way that it does whatever the software(computer programs) tells it to do.
There are 4 basic operation which a computer performs irrespective of the program which is running on it. They are classified as:-

1-Input :-









This is for the purpose of inserting or feeding data into the computer by means of an input device like keyboard.








2- Processing:-









Some kind of processing is done in the computer to take out or transform the data in some way.










3- Output:-










The computer produces output on a device, such as printer or out or monitor, that show the result of processing operation .








4- Storage:-







The computer stores the result of processing operations for future use in some storage device like hard disk or floppy disk.

Components of Digital Computers

A digital computer can be broadly classified as a collection of four components. They are:


1. Input Unit-
The input Unit provides an interface between the users and the machine, for inputting data and instruction etc. one of the most common examples is the keyboard. Data can be input in many more forms – audio, visual, graphical etc.
Some input device are:


1. Keyboard
2. Mouse
3. Voice data entry
4. Joy stick
5. Light pen
6. Scanner
2. Output Unit


Like the input Unit, the Output Unit also provides an interface between the user and the machine. A common example is the visual display unit of a personal computer. The output unit receives the data from the CPU in the form of binary bits. This is then converted into a desired form (graphical, audio, visual etc) understandable by the user.

Some common output devices are:
1. VDU(Visual Display Unit).
2. Printers Speakers
3. Secondary Storage Devices.
4. The Central Processing Unit

The central processing unit is the brain of the computers system. The input and output devices may vary for defferent application, but there is only one CPU for a particular Computer. The specifications of computer are basically characterized by its Central Processing Unit.

1. The Arithmetic Logic Unit.
2. The Control Unit
3. Main Memory


5. The Main Memory Unit
The main memory also known as the primary memory is a part of the central processing unit and is a combination of both RAM and ROM. We shall discus the RAM and ROM later .

RAM- Random Access Memory is a read write memory i.e. information can be read as well as written into this type of memory. It is volatile in nature, i.e., the information it contains is lost as soon as the system is shut down unless ‘saved’ for further usage by users. It is basically used to store programs and data during the computer’s operation.

ROM- Read Only Memory as the name may suggest contains information that can only be read, i.e., you cam’t write on this type of memory. It is non-volatile or permanent in nature. It is basically used to store permanent programs such as program for the functioning of the monitor.

The Computer Generation

In recent years, the computer industry has grow at a phenomenal pace. In a short time of 35 years or so computers have improved tremendously. In the last decade the speed of computer has increase. The cast per unit of calculating has gone down by 500 times. The storage capacity is increasing so fast that now it seems that nothing is impossible to store. Large data can be stored in very small devices. Read More

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First Generation of computer(1942-1955):-




Until 1951, electronic computers were exclusive possession of scientists and the military. Till then nobody tried to use them for business purpose. The idea of marketing them was conceived mushily and Eckert, creators of ENIAC’S. as US census bureau was already using IBCP cards, they were the pioneers in US buying this computer for the first time in 1951. the company created by M and ETS become UNIVAC division of Sperry and Corporation (later known as UNISYS).




Computer belonging to this generation had the following characteristics:


1. Comparatively large in size as composed to present day computers.
2. Generated lot of heat, they were not consistent and reliable as the valves tended to fall frequently.
3. low capacity internal storage.
4. individual, non-related models.
5. processors operated in the milliseconds speed range.
6. internal storage consisted of magnetic drum and delay lines.




Second Generation (1955-1964):






FGC were very unreliable, mainly because of vacuum tubes which kept on burning out. Users had to be prepared all the time with dizen of extra tubes to replace them. The computers of this generation were characterized by the use of Solid State devices(transistors) misted of vacuum tubes. Transistorized circuits were smaller, generated little heat, were expensive and consumed less power than vacuum tube circuits and were much greater in processing capacity.


Since transistors had a faster switching action, this generation than first generation computers. The use of magnetic cores as the primary internal storage medium and the introduction of removable magnetic disc pack were other major developments of the second generation. Although magnetic tapes were still used commonly. These computers had built in error detecting devices and more efficient means were developed to input and retrieve from the computer.






Some of the popular models in this generation of computer systems, we IBM-1401, IBM-1620, BURROUGHS B-200 SERIES, HONEY-WELL H-400, these computers were used for business applications.


Third Generation of Computer(1964-1975)






A revolution in the computer developments took place with the development of integrated circuits (IC) on a single silicon chip. In 1958, jack St Clair Kebly and Robert Noyce invented the first IC. IC incorporated number of transistors and electronic circuits on a single wafer or chip of silicon IC is called chip beause of the way they are made. They are also called as semi conductors as combining layers of materials that have varying capacity to conduct electricity from them.


This ushered in the third generation of computer systems in 1964. the integrated circuits enhanced considerably the processing capability of placing 12 or more logic gates on a single chip was developed into a well-defined technology was redefined to a point where hundreds or more gates could be placed on a chip of silicon and incorporated as functional logic block in an overall system.




Computers of this generation have the following characteristicts:




1. Smaller in size as compared to second generation computers.
2. Higher capacity internal storage.
3. Remote communication facilities.
4. Multiprogramming facilities.
5. Reduced cost of access storage.
6. Processors, which operate in nanosecond speed range.
7. Use of high level languages such as COBOL.
8. Wide range of optional peripherals.


Fourth Generation of Computer (1975-1989)






The 1970’s marked the beginning of a new generation of computers, produced by computer giants like IBM, ICL, CNR and Burrought. From design viewpoint, the new generation provided increased input-output capability, longer component life as well as greater system reliability. From the functional view point, new powerful language were developed to broaden the use of multiprogramming and multiprocessing and major shift from batch processing to on line, remote interactive processing.




The development of microprocessor chip, which contains an entire Central Processing Unit(CPU) on a single silicon chip led to the mushroom growth of inexpensive computers. They are not computers by themselves but they can perform all the functions of arithmetic logic unit and control units of the CPU. When these microprocessor are connected with memory and input-output devices, they become microcomputers.


The use of very large integrated circuits (VLSI) has made the froth generation (micro) computers very compact, much less expensive, faster, more reliable and of much greater data processing capacity than equalized third generation computers.


Some computers belonging to fourth generation are DEC-10, STAR-1000, PDP-11 AND APPLE Series Personal computers.




Fifth Generation Computers (1989-Present)






Till fourth generation of computers, the major stress was on improving the hardware from values to transistors and then to integrated circuits, which resulted in miniaturization and fast speed of computers. Hardware, the lack of thinking power has forced the scientists to work further for fifth generation computers.


The concept of “Artificial Intelligence” is being used in these computers and Japanese call them “Knowledge Processors”. Automatic programming, computational logic, pattern recognition and control of robots, the processes and which need skill and intelligence are examples of Artificial Intelligence. These computers, when developed, will have be able to execute billion of instructions per second and will have unimaginable storage capacities. The present day high level languages will become obsolete on these machines and new computer language and related software will be needed.


Computers of this generation have the following characteristics:


1.Easy to computers with high intelligence and natural human input and output mechanism;


2.Reliable and efficient software development by new languages, new computer architectures and systems software which overcome previous problems;


3.Improved overall functions and performance aimed at making computers smaller, lighter, faster, faster, of greater capacity, more flexible and more reliable

The Central Processing Unit

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The Central Processing unit is the brain of the computers system. The input and output devices may vary for different application, but there is only one CPU for a particular computer. The specifications of a computer are basically characterized by its Central Processing Unit.

The CPU processes the data it receives as input (either through input devices or through the memory). As mentioned earlier the CPU receives the data in the from of binary bits, which it can understand.

1. the CPU can perform arithmetic calculation such as addition, subtraction etc.
2. the CPU can perform logical decisions.
3. The CPU with the help of other devoices can perform data transmission.
4. The CPU can perform manipulating tasks such as word processing.
5. After performing the required task the CPU may place results in memory or send results to the output device according to the instruction given to it.



The central processing unit can be further divided into:


1. Arithmetic Logic Unit(ALU)-

As the name may indicate the arithmetic logic unit performs all arithmetic and logic calculations on the data it receives.


2. Arithmetic Calculations-

The arithmetic calculations may be addition, subtraction, multiplication, division, exponentiation etc.

3. Logical Calculation-

Logical calculations are basically decision making statements. For example, A>B, decides whether is A is greater B or not; IF A is greater than B the statement is true and logical ‘1’ would be generated, otherwise a logical ‘0’ would be generated. Some logical decide the further routing of the program.

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Processor and Memory

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Introduction-

The processing unit in a computer interest instructions given in a programs and carries out the instructions. Processors are designed to interpret a specified number of instruction codes. Each instruction code is a string of binary digits. All processors have input/outputs instructions, arithmetic instructions, to manipulate characters. The number and type of instructions available differ from processor to processor.

A memory or store is required in a computer to store programs and the data processed by programs. A memory is made up of a large number of cells, with each cell capable of storing one bit. The cells may be organized as a set of addressable words, each word storing a sequence of bits. In one such address of the word. This organization, called a Random Access Memory (RAM), is used as the main memory of computers. Another organization arranges cells in a linear sequence to from a serial access memory.


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Control Unit –

Control Unit –

The control unit controls the entire operations of the computer and the CPU. It controls all the other devices connected the CPU. Input devices, output devices, auxiliary Memory etc. hence, the control acts as the never centre of the computer.
The control unit upon receiving an instruction decides what is to be done with it. That is, whether it is to be sent to the ALU for further processing or to the output devices or to the memory etc. in other words the control unit coordinates and controls all hardware operations.

The control unit has an electronic clock that transmits electronic pulses at equal interval of time. The control unit gives instructions to other devices based upon these pulses. Suppose there are three instructions to be performed. Let the first instructions take three clock pulses to complete; when the fourth clock pulse is received the control unit would start processing the second instruction and so on. Suppose an instruction takes three and for the fourth clock pulse to complete and take up the next instruction with the fifth clock. Pulse.

Registers –

The CPU consists of a set of registers which are used for various operations during the execution of instructions. CPU needs registers for storing instructions as well as for storage and manipulation of temporary results.

1. Fetch: To bring the instructions from main memory into the instruction register.

2. Decode: Decoding means interpretation of the instruction to decide which course of action is to be taken for execution of the instruction and what sequence of control singles must be generated for it.



3. Execute: The instruction is execute after the fetching of operands is complete. The control unit is responsible for sequencing the steps necessary to complete.

Input Devices

Keyboard Devices:

Most input data is entered input the computer by using a keyboard. This input methods is similar to typing on a typewriters.

Most typewriters and computer keyboards are Qwerty Keyboards. The alphabetic keys are arranged so that the upper-left row of letters begins with the six letters QWERTY. Designers of other keyboards claim that their boards are easier to learn than the QWERTY keyboard.

Computer keyboards

Include keys that are designed to perform specific tasks. These special keys include function keys, directional keys and special-purpose keys such as Alt, Ctrl, Enter, Ins, and Esc. These keys enable the user to perform complex tasks easily when using the application.

Some of keyboards have even 112 keys, with three new keys designed to simplify working with Windows 98. two of these keys, next to the Alt key, bring up Start menu. The third key, next to the right Ctrl key, brings up a menu of functions that are frequently accessed in whichever application is currently being used.


Point and Draw Devices : Many people use devices instead of keyboards whenever possible. Pointing devices minimize the amount of typing (consequently, the number of errors). The many pointing devices available include the mouse, trackball, light pen, digitizing tablet, touch screen and pen-based systems.




The Mouse and Track Ball: The mouse is a palm-size device with a ball built into the button. The mouse is usually connected to the computer by the cable (computer wires are frequently called cables) and many have from one to four buttons (usually two). The mouse may be mechanical or optical and comes in many shapes and sizes. When you move the mouse over a smooth surface, the calls rolls, and the pointer on the display screen moves in the same direction. The Apple Macintosh, with its graphical user interface, made the mouse popular. Now, most microcomputer systems, regardless of the manufacturer, use a mouse. With the mouse, you can draw, select options from a menu and modify or move text. You issue commands by pointing with the pointer and clicking a operating a microcomputer easier for beginning users.



Touchpad:

The touch pad is a stationary pointing devices that people find less tiring to use than a mouse or a track ball. The movement of a finger across a small touch surface is translated into cursor movement on the computer screen. The touch sensitivity surface may be just 1.5- 2 inch square, so the finger does not have to move much. Its size makes it most suitable for the notebooks or the laptops.

A device

That was released in 1995 enables the user to move the cursor using and infrared pen. The pen is cordless and works when it is as fifteen feet from the screen. Although the mouse is still the most pointing device, these innovations may change that in future.



Joysticks:
A joysticks is a pointing device often used for playing games. The joystick has a gearshift-like lever that is used to move the pointer on the screed. On most joysticks, a button on the top is used to select options. In industry and manufacturing, joysticks are used to control robots. Flight simulators and other training simulators also use joysticks.


Touch-Sensitive Screens:

Perhaps the easiest way to enter data is with the touch of finger. Touch screens enable the user to select and option by pressing a specific part of the screen. Touch screens are commonly used in grocery stores, fast-food restaurants and information kiosks.

Data Scanning Devices

Data Scanning Devices



Optical Recognition System:

Optical Recognition System provide another means of minimizing keyed input by capturing data at the source. These systems enable the computer to “red” data by scanning printed text for recognizable patterns.

The banking industry developed one of the earliest scanning systems in the 1950’s for processing cheque. The Magnetic link Character Recognition (MICR) system is still used throughout the banking industry. The bank, branch, account number and cheque number are encoded on the cheque before it is sent to the customer. After the customer has used the cheque and it comes back to the bank to the bank, all that needs to be entered manually is the amount. MICRO has not been adopted by other industries because the character set has only fourteen symbols.



Bar Code Reader:

Of all the scanning devices, you are probably most familiar with BAR CODE READES. Many retail and grocery stores use some from of bar code reader to determine the item being sold and to retrieve the item price from a computer system. The code reader may be a handled unit or it may be embedded in a countertop. The bar code reader reads the Universal Product Code(UPC), a pattern of bars printed on merchandise. The UPS has gained the use of the code because the system was used to check their accuracy and speed. Today, bar codes are used to update inventory and ensure correct pricing. Federal Express employees can usually tell a customer within a matter of minutes the location of any package.


Optical Mark Reader:

By taking exams, you are familiar with Mark Sense Character Recognition systems. Every time you take a test with a “fill in the bubble” Scranton from and use a #2 lead pencil, you are creating input suitable for and OPTICAL MARK READER (ORMO. A #2 lead pencil works best because of the number of magnetic particles in that weight lead. The OMR sense the magnetized marks, enabling the reader to determine which responses are marked.

Optical Scanners:

Can scan typed documents, pictures, graphics or even handwriting into a computer. Photographs scanned into a microcomputer appear clearly on the screen and can be displayed whenever desired. The copy that the computer stores never yellows with age. Early scanners could recognize only text printed in a special OPTICAL CHARACTER RECOGNITION(OCR) typeface. A scanner converts the image that it sees into numeric digits before storing it in the computer. This conversion process in known as DIGIZING.

Depending on the volume and type of material to be scanned, you can use drum scanner, flatbed scanner, sheeted scanner and even small handheld scanners. The small, hadheld scanner sheeted scanners(priced at about $150) are used most frequently with micro microcomputer; however, only 5 per cent of all microcomputer systems are equipped with scanners. Manufacturers responded to user reluctance to use scanners by releasing in 1995 a number of new, small paper scanners priced between $500 and $700.) most of these new devices sit between the keyboard and the monitor and can interface with a fax machine, send e-mail, and store documents on disk for archive purposes.

Digitizer:

Digitizer is used to create drawing and pictures using a digitizer tablet by a process called digitizing. Digitizing is a process by which graphic representations are converted into digitizer consist of 3 main parts – a flat surface called tablet, a small hand held mouse-like device called puck and a special pen like device called stylus. The puck is used to input existing drawings into the computer. The stylus is used to trace exiting drawing placed on the tablet. The user makes contact to the tablet with stylus. As the stylus is connected to the tablet by a write, the traced image is stored in RAM and displayed on the monitor.


Electronic Card Reader:

Before discussing electronic card reader, let we discuss electronic credit cards. Electronic credit card make it possible to charge online payments to one’s credit card account. It is card details can be encrypted by using the SSL. Protocol in the buyer’s computer, which is available in standard browsers. The number of input devices are common in association with ash transactions. The most common are ATMs and POS terminals.

1. ATM:

Automatic Taller Machine are interactive input/output devices the enable people to make bank transactions from remote locations. ATMs utilize screen input as well as magnetic card readers.

2. POS:
Point of Sale: terminals are computerized cash registers that also often incorporate touch screen technology and bar-code scanners. These devices allow the input of numerous data such as item sold, price, method of payment, name or Zip code of the buyer, and so on. Some inputs are automated; others may be entered by the operators.

Vision Input System:

Are the latest input devices that can recognize the vision/image which appears in the range of its lens. It seems to be vary useful and are becoming popular in different Got. Departments like licensing, passport department and other authorities where personal identification is required.

Output Devices

Output devices are hardware components which are used to display or print the processed information. We are discussing below the structure, working and uses of the common output devices are:

Monitor:

Visual Display Unit(VDU), commonly called as monitor is the main output devices of a computer. It consists of a Cathode Ray Tube(CTR), which displays characters as an output. It forms images from tiny dots called pixels, that are arranged in a rectangular form. The sharpness of the image (screen resolution) depends upon the number of pixels.

Types of monitors:

There are different kinds of monitors depending upon the number of pixels. Depending upon the resolution, monitors can be classified as follows.

a.CGA (Color Graphics Adapter).
b. MDA (Monochrome Display Adapter).
c. HGA (Hercules Display Adapter).
d. EGA (Enhanced Graphics Adapter).
e. VGA(Video Graphics Adapter).
f. SVGA(Super VGA).

Printer

Printer

Printer is the most important output device, which is used to print information on paper. Printers are essential for getting output of any computer based application.

Types of Printers:

There are many types of computer which are classified on various criteria. Printers can be broadly categorized into the following two types:


a. Impact Printers:

The characters by striking against the ribbon and onto the paper, are called Impact Printers. These printers are of two types –


1. Character Printer. 2. Line Printers.




b. Not Impact Printers:

The printers that print the characters without striking against the ribbon and onto the paper, are called Non-Impact Printers. These printers print a complete page at a time, therefore, also Printers.

1. Ink Jet Printers. 2. Thermal Printers.

Plotter

Plotter


Plotter
is an important output device. Used to print high quality graphics and drawings. Although the graphics can be printed on printers, the resolution of such printing is limited on printers. Plotters are generally used for printing/drawing graphical images such as charts, drawings, maps. Of engineering and scientific application.

Some important types of printers are:

a.) Flat Bed Plotters:
These plotters print the graphical images by moving the pen on stationary flat surface material. They produce very accurate drawings.

b.) Drum Plotters:
These plotters print graphical images by moving both the pen and the drum having paper. They do not produce as accurate drawings as printed by flat bed plotters.

c.)Inkjet Plotters: These plotters use inkjet in place of pens. They are faster than flat bed plotters and can print multi-colored large drawings.