7- COMPONENTS OF A COMPUTER SYSTEM

The computer (Hardware), users (Liveware) and programs or applications (Software) works together, which is called computer system. In a computer system, the CPU, input device and output device called hardware are interconnected.

 

COMPONENTS OF COMPUTER:  

• Computer hardware.
• Computer software.
• Liveware.

COMPUTER HARDWARE:

Includes a physical parts of a computer, called hardware. They are interconnected to each other. The hardware of a computer are given below:

1. Input device.
2. Central Processing Unit (CPU).
3. Output device.

 

1- INPUT DEVICE:

These components help users enter data and commands into a computer system. Data can be in the form of numbers, letters, signs, symbols, images, sounds, actions, commands, etc. The main function of input device is to direct commands and data into computers. Computers then use their CPU to process this data and produce output as results. 

 

Some main input devices are given below:

• Key board
• Mouse
• Joystick
• Light pen
• Graphic tablet
• Touch screen
• Track ball
• Scanner
• Touch pad
• OMR, OCR, BCR, MICR, QR Code etc. 

KEY BOARD:

A keyboard is one of the primary input devices, used with a computer. Similar to an electric typewriter, a keyboard is composed of buttons used to create letters, numbers, signs/symbols, and perform additional functions.

 

 

The standard computer keyboards typically contain 101 keys for inputting character sets including alphabets, numbers, symbols, or functions. Other keyboard configurations may include more than 104 keys. Gaming keyboards, Multimedia keyboards, or programmable keyboards often have 110 to 115 keys.

 

There are six types of keys in a standard key board given below:

• Alphabetical keys: (A to Z, small or capital letters)
• Numerical keys: (0 to 9, in two sets)
• Function keys: (F1 to F12 keys)
• Arrow keys (cursor keys, direction keys, navigation keys): Left, Right, Up, Dn arrow keys.
  
• Sign or symbol keys: ~,`,!,@,#,$,%,^,&,*,(,),_,-,+,=,{},[],\,|,:,;,',",<,>,?,/ etc.
  
• Special keys: Esc, Tab, Capslock, Shift, Ctrl, Alt, Windows, Spacebar, Application, Backspace, Enter, Insert, Del, Home, End, PgUp, PgDn, Srcnprint, Scroll lock, numluck, Sleep, Wakeup, Pause/Break etc.

MOUSE:

A computer mouse is a main handheld hardware input device that controls a cursor in a GUI (graphical user interface) based operating system and can move or select text, icons, files, and folders on your computer. It is also used for processing instant commands and drawing a design. 

 

There are two main button and wheel in a mouse with their functions given below:

• Left Button (Single click): Select an icon (click & drag), opens drop down menu's, toggle buttons or switches.
• Left Button (Double click): Open an icon, image and flowers. 
• Right Button (Single click): Often brings up shortcut menus and other options not normally shown on the screen.
• Wheel and Center button: This button is not found on all mice however it is very useful. Rolling the button will allow you so scroll up and down a long document. The wheel also acts like a 3rd button on the mouse and can be depressed. If one clicks the wheel button one will be able to automatically scroll up or down a page. Moving the whole mouse will allow one to adjust the direction and speed of the scrolling. This Page has intentionally been made long. You may practice using your mouse to scroll here.
  
  
  

TYPES OF MOUSE:

The main three types of mouse as given below:

• Mechanical Mouse: Houses a hard rubber ball that rolls as the mouse is moved. Sensors inside the mouse body detect the movement and translate it into information that the computer interprets.
  
• Optical Mouse: Uses an LED sensor to detect table top movement and then sends off that information to the computer for merry munching.
• Cordless Mouse: With both these types, the mouse relays a signal to a base station wired to the computer’s mouse port. The cordless mouse requires power, which comes in the form of batteries.
  

 

JOYSTICKS:

A joystick is an input device that can be used for controlling the movement of the cursor or a pointer in a computer device. Joysticks are often used to control video games, in graphic applications and usually have one or more push-buttons whose state can also be read by the computer.

LIGHT PEN:

A light pen is a light-sensitive computer input device, basically is that used to select text, draw pictures and interact with user interface elements on a computer screen or monitor.  It allows the user to point to displayed objects or draw on the screen in a similar way to a touchscreen but with greater positional accuracy.

 

It consists of a photocell and an optical system placed in a small tube. When its tip is moved over the monitor screen, and pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signals to the CPU. 

 

GRAPHIC TABLET:

A graphics tablet, also called digitizer is a computer input device that enables a user to hand draw images, animations and graphics, similar to the way a person draws images by pencil on the paper. This tablet is also be used to capture data or handwritten signatures. The computer converts the drawing strokes into digital form, displaying them on the computer screen.

TOUCH SCREEN:

A touch screen is a computer screen that allows the user to give commands to the computer by touching of the screen rather than by using the keyboard or other input device.

The touchscreen technology works similar to a computer mouse. Instead of moving your pointer with a mouse and then clicking on a location, you press on the location with your finger. However, multi-touch technology makes it possible to interact with the computer display in many different ways. Tasks like scrolling up and down a webpage, selecting text and drag-and-drop have become very easy to us by touchscreen technology.

TRACK BALL:

A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes. Users roll the ball to position the on-screen pointer, using their thumb, fingers, or commonly the palm of the hand while using the fingertips to press the mouse buttons. 

 

The user rolls the ball to direct the cursor to the desired place on the screen and can click one of two buttons (identical to mouse buttons) near the trackball to select computer objects or position the cursor for text entry.

 

 

SCANNER:

Scanner is an input device, which works more like a photocopy machine. It is used when some information is available on paper and it is to be transferred to the hard disk of the computer for further manipulation. 

 

Scanner captures images from the source which are available in physically then converted into a digital form that can be stored in the computer. These images can be edited before they are printed.

TOUCH PAD:

A flat surface which is senstive to touch, used mostly in laptop computer to control an on-screen cursor. 

When you move your finger across the touch pad surface or place your finger on the touch pad surface and move the slightly in any direction, the corresponding mouse pointer moves around your computer screen. With a touch pad, which have on your laptop, you perform clicking to open or select things on screen by using the right and left buttons on the bottom of the touch pad. 

 

OMR (Optical Mark Reader (Recognition):

OMR (Optical Mark Reader (Recognition) is used for collecting data from “fill-in-the-bubble” forms such as educational tests, surveys, assessments, evaluations, and many other multiple choice forms. 

Optical Mark Reader (Recognition) is a method of entering data into a computer system. Optical Mark Readers reads pencil or pen marks made in predefined positions on paper forms as responses to questions or tick list prompts. The OMR data entry system contains the information to convert the presence or absence of marks into a computer data file. 

OCR (Optical Character Reader (Recognition):

Optical Character Recognition or OCR is a input technology that enables you to convert different types of documents, such as scanned paper documents, PDF files or images captured by a digital camera into editable and searchable data.

 

Suppose you wanted to digitize a magazine article or a printed contract. You could spend hours retyping and then correcting misprints. Or you could convert all the required materials into digital format in several minutes using a scanner (or a digital camera) and Optical Character Recognition software.

 

BCR (Barcode Reader):

A barcode reader is an optical scanner that can read printed barcodes, decode the data contained in the barcode and send the data to a computer.

 

It consists of a light source, a lens and a light sensor translating for optical impulses into electrical signals.

 

MICR (Magnetic Ink Character Recognition):

MICR (Magnetic Ink Character Recognition),  is a font capable of recognition using magnetically charged ink. The certain computers software can print or read the character printed in such ink. The MICR refers to the line of numbers that appears at the bottom of a cheque or demand draft. The MICR line is a group of three numbers, which are the check number, account number and bank routing number. 

 

Features of MICR:

• Line on the bottom of a personal check that includes the account, routing, and check numbers. 
• Readable by individuals and computers, where its special font helps limit check fraud.
• The technology is also used to print financial forms, credit card invoices, and rebate coupons.
• MICR benefits include quickly facilitating routing information and making it difficult to alter checks.

QR code (Quick Response code):

QR Code is a two-dimensional barcode which stores information as a series of pixels in a square shape grid. Most of the time the data is a link of product information, address, structural information, advertising campaigns, biometric details or website (URL).

 

It can be scanned using a QR scanner or a smartphone with camera. Once scanned, software on the device converts the dots within the code into numbers or a strings of characters.

 

 

 

 

 

 

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6- CLASSIFICATION OF COMPUTER

We see many Computers nearby, But they all are different from each other. In this chapter, we are going to know about the basics and classification of computers which included all the different types of computers.

We can classify computer according to the following three categories:

• On the basis of Hardware and design and type.
• On the basis of Purposes.
• On the basis of Size.

On the basis of Hardware design and type:

There are three types of computer basis on hardware design and type;

1. Analog Computer.
2. Digital Computer.
3. Hybrid Computer.

1- Analog Computer:

An analog computer performs tasks using continuous data (the physical amount that changes continuously). Analog computers are used primarily to measure physical units like voltage, pressure, electric current, temperature, and convert them into digits.

 

Any things that is variable with respect to time and continuous can be claimed as analog just like an analog clock measures time by means of the distance traveled for the spokes of the clock around the circular dial.

 

It is used to measure and perform arithmetic calculations of numbers, the length of an object, or the amount of voltage that passes through a point in an electrical circuit. Analog computers obtain all their data from some measurement way.

 

Analog computers are mainly used in the fields of science and engineering. Analog computers are slow and equipped to measure things rather than countable or check. 

 

Example of Analog computer: Mercury thermometer, Needle clock, E6B flight computer, Deltar, Librascope, aircraft weight and balance computer etc.

2- Digital Computer:

A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system because this computer understands only digits i.e. 0’s and 1’s. All the content that is written in English will be converted to binary language and thus computers and humans communicate with each other. 

 

These are the devices through which we provide some input and get the output within a fraction of seconds.

Example of Digital computer: Desktop, Laptop, Notebook, Ipad, Smartphone, E-reader, Flash drive, Digital Camera etc.

3- Hybrid Computer:

Hybrid computers are computers that exhibit features of Analog computers and Digital computers. The digital component normally serves as the controller and provides logical and numerical operations, while the analog component often serves as a solver of differential equations and other mathematically complex equations.

 

Hybrid computer are used in several applications such as:

• Petrol pump – Measurement convert fuel flow into currency rate.
• Measurement of patient’s heartbeat.
• Scientific laboratory.
• Applied psychology.
• Control industrial process.
• Defense sector.
• Airlines sector.
• Ships.
• Cement plant.
• Gas Pump Station.
• Radar systems.
• Scientific calculations.
• Weather system computation. 
• Monitoring and controlling nuclear reactor.
  
• Electrocardiogram machine.
  
• Echocardiogram machine.
  
• Ultrasound machine.
  
• CT scan machine.
  
• Holtor Monitoring machine.
• ATM machine.
  
• Hospital – Intensive Care Unit (ICU).
  
• Car that runs on gas and electricity.
  
• Cell phone – Grab analog sound, and transform into digital signals then finally broadcast it on digital data network, and user can receive it and fed into analog speaker.

Example of hybrid computer: Thermometer, Auto gasoline pump, ICU, Ultrasound machine, CT scan machine, Electrocardiogram machine, Echocardiogram machine etc.

On the basis of Purpose:

There are two types of computer basis on purpose:

1. General purpose computer.
2. Special purpose computer.

1- General purpose computer:

A general purpose computer is one that, given the appropriate application and required time, should be able to perform most common computing tasks like word processing, documents, reports, accounting, printing, database managements, listen audio, watch video, internet surfing, e-mail e-commerce etc. 

 

Example of general purpose computer: Desktop, Laptop, Notebook, Smartphone, Ipad etc.

2- Special purpose computer:

Special purpose computers are those that are made to do special tasks. And mostly its does only one task (task related to that particular field). They are also known as dedicated computers, because they are dedicated to perform a single task over and over again.

Some uses of special purpose computer are:

• Space Science.
  
  
  
• Meteorology.
• Control of Missile in Battle field.
• Satellite operation.
• Medical and Medicine department.
• Physics and Chemistry Laboratory.
• Traffic control.
• Oceanography.
• Agriculture Science
• Engineering Design.

Example of special purpose computer:  ATM, Wishing machine, Weather forecasting simulator, Traffic control computer, Defence oriented computers, Traffic light controller, Military planes controlling computers, Oil exploration system, Surveillance equipment etc.

 

 On the basis of Size:

 

There are four types of computer basis on size:

1. Micro Computer.
2. Mini Computer.
3. Mainframe Computer.
4. Super Computer. 

1- Micro computer:

Micro computer, an electronic device with a microprocessor as its central processing unit (CPU). After the invention of microprocessor, it became possible to create Micro computer. Micro computer was formerly a commonly used term for personal computers, particularly any of a class of small digital computers whose CPU is contained on a single integrated semiconductor chip. 

Through this, in any business, letter drafting, applications, reports, documents, accounting, database management, listen to songs, watch videos etc. works are done by this computer. The price of this computer is up to 1 lac.

2- Mini computer:

A minicomputer is a computer which has all the features of a large size computer, but its size is smaller than those. A minicomputer lies between the mainframe and the microcomputer because its size is smaller than the former one and larger than the latter one.

 

Mini computers may contain one or more processors, support multiprocessing and tasking, and are generally resilient to high workloads. Although they are smaller than mainframe or supercomputers, minicomputers are more powerful than personal computers and workstations.  

 

Mini computers are used for Scientific and Engineering computations, Business-transaction processing, preparing of large Payroll, Costs analysis, Sales analysis, Production planning, Reservation system, in Banks, File handling, and Database Management, and are often now referred to as small or midsize servers. Its cost is of near about 1 million or more.

3- Mainframe computer:

Mainframe computer likes as a big centralized machine that contains the large memory, huge storage space, multiple high grade processors, so it has ultra processing power compare to micro and mini computers.

 

So, the importance of mainframe is increasing for large scale organization, scientific research, consumer statistics, and census data, because it is capable to execute multiple complex programs concurrently at the ultra speed.  

Mainframe computers are very expensive, and these types of computer cannot be used in the home. Due to its more processing power, they are used by large scale companies, banks, other government sectors, e-tickets, stock-exchange, insurance sectors, telecommunications, finance sectors, reservation system for railway and airlines etc. 

 

The mainframe computer kept on for 24 hours because its used for central computer to a specific departments. The cost of mainframe computers are near about 10 million or more.

4- Super computer:

Supercomputers have a huge performance compare to other using general purpose computer because its architectural and operational model depend on the parallel and grid processing. Primary motive to design of supercomputer was to be used in large scale organizations where need more computing power.

Supercomputer has a power to execute many processes simultaneously on thousand of processors, because these types of processors can execute billions and trillion of instructions per seconds, so its computing performance matrix is FLOPS (that is floating-point operations per second). So these types of supercomputers are more expensive they can 5 million dollars to 200 million dollars.

 

The main functions of supercomputer are:

• The super computers are able to solve large amount of calculations and complicated calculation as well.
• Hundreds users are capable to access multiple tasks at same times.
• Researches and discovery in large amount of scientific research and laboratories.
• Sending astronauts to space travel.
• Weather forecasts.
• Animation films.
• Launching and monitoring satellites.
• For oil and gas exploration, converting seismic data into maps that indicate where to drill oil and/or gas wells. 

Example of supercomputer: Titan, IBM sequoia, K computer, Tianhe-1, Jaguar, IBM Roadrunner, Nebulae, Kraken, Pleiades, Jugane, Cray/HPE Piz Daint, Dell frontera, Nudt Tianhe-2, Sunway Taihulight, Summit, Param Al and Mihir, Pratiyush, Padma, Anupam, Anurag, Aditya, Bramha, Shivay etc.