Computer Basic

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Computer Basic What is Computer ? Computer is an electronic device which takes in data and information process it and gives the result according to our requirement, faster the human being. What is computer System ? Computer system is combination of Hardware, Software and User.

 Hardware Physical part of computer which we can touch and see is called Hardware such as- Monitor, motherboard, keyboard.  Software Software is a way to control computer hardware. Software is collection of programs which performs any task.  User The person who works on computer or create the programs called user.

How many basic parts of Computer ? Computer basically has following three parts- i) Input Unit ii) Output Unit and iii)CPU a. Input Unit The unit by the help of it we insert data and information in computer is called Input Unit such as Keyboard, mouse, scanner etc. b. Output Unit The unit which display the result is called Out put unit. Such as Monitor, Printer, Speaker. c. Central Processing Unit(CPU) CPU is brain of computer. It is main part of computer. All processing work, storage and controlling is done by this unit. It can be divided in three parts.

1. Control Unit (CU) C.U. is very important part of computer which controls all hardware devices, software and other activities. 2. Memory Unit The unit which stores data, information, instruction and result is called Memory unit. 3. ALU(Arithmetic and Logic Unit) This unit is responsible for arithmetic and logical operations.

Block-Diagram of Computer

Data Data is raw facts and figures which is given to the computer. Information Information is processed date which we get after processing. Or A meaningful data is called information. Processing Conversion of raw data into meaningful data is called processing.

Resister Register is an electronic components which stores instruction during processing. It is a fast memory. Strength of Computer Computer has following characteristics (Strength)  Speed  High Storage Capacity  Accuracy  Reliability  Versatility Weakness of Computer  Lack of Decision Making Power  Zero IQ Memory in Computer system Computer receives the instruction, data and result which is store in a device during processing which is called Memory. This memory is two types- i) Primary Memory ii) Secondary Memory Main Memory(Primary memory) The computer main memory or internal memory is used to store program and data during processing. It is two types. i) Rom(Read Only Memory) ii) Ram(Random Access Memory)

Rom(Read Only Memory) In this memory, information is permanently stored and cannot be changed. Means only can read. Rom contains the setup instruction which remain stored even if power is turned off.

Ram(Random Access Memory) The internal memory of computer in which we can read or write is called Ram. It is very important to do work on computer. Ram is responsible for the processing speed of computer. When open any program or play game first it copy in the RAM then start work. Ram has limited storage capacity and volatile in nature means if power is off contain also removed.

Units of Memory Computers store and process data/information in the form of binary numbers. A binary number has two digits 1 and 0 and is known as Bit. 1 means “On or High voltage” and 0 means “Off of Low voltage”. Each character is represented by a group of 8 bits.

Cache Memory Cache Memory is a special very high-speed memory. It is used to speed up and synchronizing with high-speed CPU. Cache memory is costlier than main memory or disk memory but economical than CPU registers. Cache memory is an extremely fast memory type that acts as a buffer between RAM and the CPU.

Secondary Memory (Storage Device) Primary memory cannot stores data and information permanently therefore secondary storage device is used to store data permanently. They are various types such as- Floppy, Hard disk, CD and DVD Some storage device with their storage capacity(Max.)

Floppy 1.44 MB CD 700 MB DVD 4.7 GB HD 1 TB PEN DRIVE 2 GB to 128 GB

Difference between Primary memory and Secondary Memory Primary Memory Secondary Memory  Directly connected to CPU  Not directly connected to CPU  Memory is volatile  Non volatile  Direct access by CPU  Indirect access by CPU  Faster data access  Slower data access  Used for processing data  Used for storing data  Small in size  Large in size

Types of Software A software is a way to control computer hardware Or Software is collection of programs which performs specific task. By help of these different program we take the work by computer hardware. Software can be divided in two parts- 1. System Software 2. Application Software

System Software :- System software refers to the programs that control internal computer operations and make best use of hardware. It classified in three parts- a) Operating System b) Language Processor(System Development Software) c) Utility Software

Operating System :-An Operating system is a program which acts as an interface between a user and the computer hardware. Operating System is the main program which control the all activity of hardware and also base of system software. Without system software we cannot operate application software.

Language Processor A language processor is a program which converts high level language in to machine language. Computer can understand only machine language

so to give instruction in low level language (machine language) we required language processor. They are three types-

i) Assembler ii) Interpreter iii) Compiler

i) Assembler ;- The language processor converts the program written in assembly language into machine language.

ii) Interpreter: It is language processor, converts a HLL program into LLL and executes it line by line. If there is any error then report it and stop the execution of program. Such as -Basic

iii) Compiler : It is also language processor. It coverts entire HLL programs into LLL and if no error then execute. If error then report it with line number. Such as – C++, , Cobol etc. Utility Software Utility software is software designed to help to analyze, configure and maintain a computer hardware ware and other software. Such as- Antivirus software, File management software.

Application Software Application software is the set of program which performs specific type work. Such as reservation software, result software, office work software, drawing software. Application software again categories in three parts- 7

 General Purpose Software  Specific Purpose Software  Customised software

General Purpose Software These software are created for general purpose and can be run on any computer, any place, and any country. Their working is similar. Such as Ms-Office, Photoshop, Game software, Data base software, Presentation software, Multimedia software

Specific Purpose Software These software are designed for special purpose. Such as a school fees software is designed for particular school. It cannot be run in other school because every school has different fess structure. Some more example of Specific Purpose software is given below-  Accounting Management Software  Reservation Software  Human Resource Software  Inventory Control Software  Billing Software

Customised software(Bespoke Software) This type of software is prepared according to use’s requirement. In this type software we first find out requirement of use’s then create it. This type software is known as tailor made or bespoke software.

Advantages  The user will get exact software which he need.  Save the time and money  Speedup the working of company Disadvantage  It takes lot of time to develop. 8

 More cost then general software.  To run this type software training is required

Basics of Operating Systems An Operating System is a program, which acts as an interface between a use and computer hardware. OS is an important component of computer system which controls all components of computer system.

Role of Operating System The Operating system provides certain services which given below-

a) Program Execution b) Handling Input/ Output Operations c) Manipulation of File System d) Error Detection and Handling e) Resource Allocation f) Accounting g) Information and Resource Protection h) Providing User Interface

Need of Operating System Computer hardware is a designed machine only. It only does the work according to instruction which is given in form of 1 and 0. Operating system is main program who know how any work is done by help of hardware. We give any instruction then OS takes all decision and perform the work by help of hardware and other software. So OS play a very important role in computer system. We cannot work on system without

OS. Operating system is base of any computer. It is system software and in absence of OS we cannot run application software. What is Shell In operating system there are two main components Shell and Kernel. Shell part is responsible for interacting with the user. It get the command from the user. Then translate the commands into machine language and then pass it to the Kernel for further processing.

What is Kernel A kernel is the core part of an operating system.. It functions at a basic level communicating with the actual hardware and managing resources such as CPU and memory. So It works as an interface between the user application and the hardware.

Functions of Operating System Function of Operating system is given below  Process management  Memory Management  File Management  Device Management  User Interface

What is Device Driver A device driver is a group of files that enable one or more hardware devices to communicate with the computer’s operating system.

Types of OS There are different types of operating system. Some are given below  Single user OS This type of OS is used only those system which has only one terminal. They are two types- Single Task OS- such as:- Ms-Dos 10

Single User, multitasking- such as:-windows, Vista, Linux, Mac OS  Multiprogramming OS This type of OS supports multiprogramming so more than one use can work. Such as-Unix, Linux, IBM AS400  Time Sharing OS Time-sharing systems were developed with the main aim to provide fast response to the request made by user. In this type OS, CPU fairly share the time with given job. Time Sharing OS is BSD Unix, NOS/VE, Genie.  Real Time OS A real time system is mainly applied in those system where the response or feedback is immediately required. This type of OS is used in those computer which are used in factories, missile tracking, defense, and airline. Such OS is LynxOS, OSE, RT Linux  Multiprocessing OS Multiprocessing OS is used in those system where two or more CPU perform a coordinate task simultaneously. Example – Unix, Linux, Windows NT,  Distributed OS This type of OD is designed to share its work load over multiple sever. This type of OS is used for reservation system. Example- Unix, Linux, DCE, X/Open.

Operating System based Interface An operating system works as interface of a user. The way in which users communicate with computer is called an ”interface”. They are two types.

Command Line Interface (CUI or TUI) A command line interface is basic but old type OS where the user type the command by keyboard in dos prompt. Such as- MS-DOS.

Interactive Interface a) Graphical User Interface(GUI) In GUI operating system user communicate with the help of graphics. No any text command is required. b)Touch Screen Interface In touch screen interface user can select different icon by help of finger. It is used in Mobile phone and touch screen car dashboard and laptop screen. Such as- Windows 8, Windows 10, Android, iOS OS

Computer Networking, Multimedia Basics Networking Transfer of information from one place to another place by help of person, device or media is called networking. Such as- Person-network, TV-network, cable- network. Computer Networking Transfer of data or information from one place to other place by help of computer is called Computer networking. By help of networking we can share data, information, hardware and software. In network connected computer is called Workstation or Node or Host. Advantage of Networking In Computer networking two or more computer are connected to each other and can share information to each other. Networking has following advantage  It breaks the barriers of distance, cost and time.  Data transfer is less expense.  Save time and cost 12

 Sharing of hardware and software is possible  Easley transfer of text, image, audio and video is possible.  Type of Networks Computer network is used in office, school and reservation purpose. This network is differ according to requirement, speed, no of computers, cost and distance. There are four types of networks 1. Personal Area Network(PAN) 2. Local Area Network(LAN) 3. Metropolitan Area Network(MAN) 4. Wide Area Networks(WAN)

PAN (Personal Area Network) A personal area network or PAN is a computer network that enables communication between computer devices near a person. PANs can be wired such as USB or FireWire or they can be wireless such as infrared, Bluetooth and Wi-Fi. The range of a PAN typically is a few meters.

LAN (Local Area Network) Small computer network that range is max 1 km is called Local Area Network, such as network of school, office or factory. In LAN user can share resources such as printer, scanner, software and information.

MAN(Metropolitan Area Network) The computer network which covers the area about 50 km is called Metropolitan Are Network. Such as- Network of Cable-TV and Phone. This network is spread over a city to share hardware and software.

WAN (Wide Area Networks) The networks spread across countries of on a very big geographical area are known as Wide Area network. Such as- Internet. It can be a group of LAN which are connected to each other. Such as- Uses of Internet

What is Internet ? Internet is computer based word wide information network. These network may link with thousands of computers and can share information with each other. Uses of Internet Uses of the Internet in our daily life is depending on desires and goals. Activities in our daily life are decided after the use of the Internet. The Internet innovated our daily life. We spend lots of time on the Web. Some uses are given below- a) Electronic mail b) Research. b) Downloading files d) Discussion groups e) Interactive games f) Education and self-improvement g) Friendship h) Electronic newspapers and magazines. 14

Computer Network :- A computer network is a collection of interconnected computer devices which can exchange information or resources. Component of Computer Network  Node  Server  Clients  Network Hardware  Software  Communication Channel Node The term host or node refers to the computers that are attached to a network and are seeking to share the resources of network. It is also called workstations. Server A server is that computer which is responsible for storing data, sharing of software, hardware and services in a network. Network Hardware  NIC(Network Interface Card) It is a network card(hardware device) which attach to host computer for establish network connection. Now a days this connection is built-in in motherboard.  Hub A hub is a hardware device used to connect several computers together. It contains multiple ports that connects number of computers.

 Switch A switch is a smart device which is responsible for filtering and transferring data in Lan network.  Bridge A bridge is a device that links two networks together. Bridges are smart enough to know which computers are on which side of bridge, so only allow those messages are pass that side. But works on same protocols.  Router A router is a network device that forwards data from one network to other network with different protocols.  Gateway A Gateway is a network device that connects dissimilar networks. It establish a smart connection between local network and external network with different structures.

Communication Channel In computer network we used two type of Communication Channel  Wired Connection  Wireless Connection Wired Connection In Wired Computer network we use cable for transferring data from one place to another place. There are three types wire  Twisted Pair Cable  Coaxial Cable  Fiber Optic cables

Twisted Pair Cable One of the earliest guided transmission media is twisted pair cables. A twisted pair cable comprises of two separate insulated copper wires, which are twisted together and run in parallel. The copper wires are typically 1mm in diameter. One of the wires is used to transmit data and the other is the ground reference.

Coaxial Cable Coaxial cables, commonly called coax, are copper cables with metal shielding designed to provide immunity against noise and greater bandwidth. Coax can transmit signals over larger distances at a higher speed as compared to twisted pair cables .Coax has a central core of stiff copper conductor for transmitting signals. This is covered by an insulating material. The insulator is encased by a closely woven braided metal outer conductor that acts as a shield against noise. The outer conductor is again enclosed by a plastic insulating cover. The structure is shown in the following figure:

Fiber Optic cables Optical fiber cables are transparent, flexible fibers made up of glass or plastic through which light waves can pass. A bunch of fiber optic cables is shown in the following diagram −

A cross section of a fiber optic cable reveals three parts −

 Core − It is the innermost portion of an optical fiber through which light propagates. It is cylindrical in shape and it made up of a flexible glass of high refractive index. The diameter of the core of a single mode fiber is 8 – 10 μm while multimode fibers are 50 μm in diameter. It is also called the optical waveguide since it is the main channel through which light signals are transmitted.

 Cladding − The core is surrounded by a glass cladding. The glass of cladding has a lower refractive index than the core. This enables total internal reflection of light waves in the core, and eventually propagation of light waves within the core.

 Outer Coating or Jacket − The outer jacket is a thin plastic sheath or coating that is opaque to light. It prevents light rays from outside to enter the optical fiber. Fibers are typically bundles together, where each bundle is covered by a protective outer sheath that prevents the fibers from physical damage.

Wireless communication Bluetooth Bluetooth wireless technology is a short range communications technology intended to replace the cables connecting portable unit and maintaining high levels of security. Bluetooth technology is used in a local area network with a very limited coverage. Bluetooth enabled electronic devices connect and communicate wirelessly through short range devices known as Piconet .Each device can communicate simultaneously with up to seven other devices within a single Piconet. Bluetooth operating range depends on the device. Class 3 radios have a range of up to 1 meter or 3 feet Class 2 radios are most commonly found in mobile devices have a range of 10 meters or 30 feet Class 1 radios are used primarily in industrial use cases have a range of 100 meters or 300 feet. Wi-Fi Wifi stands for Wireless Fidelity. It uses Radio waves to create wireless high-speed internet and network connections. A wireless adapter is needed to create hotspots. Wifi is used in LAN applications. Its network ranges at max 100 meters and transmission speed can be up to 54 mbps. Radio Waves In the electromagnetic spectrum, all omnidirectional waves in the frequencies 3KHz to 1GHz are called radio waves. They are widely used for communications since they are easy to generate, can travel long distances and can penetrate buildings. Radio waves have omnidirectional antennas, i.e. antennas that can send signals in all directions. Microwaves Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video, and data information. Microwave radio transmission is commonly used in point-to-

point communication systems on the surface of the Earth, in satellite communications, and in deep space radio communications. Other parts of the microwave radio band are used for radars, radio navigation systems, sensor systems, and radio astronomy. Cloud Computing Cloud Computing refers to storing and accessing data and programs over the Internet instead of our computer hard disk. The cloud is just a metaphor for the Internet. They are two types

 Public Cloud

 Private Cloud