Technology

What is Pen Drive and its uses:-

Pen drive is also known as flash drive. A flash/pen drive is a data storage device that consists of flash memory(key memory) with a portable USB(universal Serial Bus) interface. USB flash drives are typically removable .rewritable and much smaller than a floppy disk.

A pen drive, or a USB flash drive, is a portable data-storage device.

Pen drives have replaced the floppy drives and have become the most popular data-storage devices among consumers in todays world. Micro, lightweight and handy, a pen drive can be easily carried from place to place by students, professionals, academicians and independent tech consultants. Currently available pen drives with storage capacities ranging from 8GB and 32GB can be used to store data.

Today flash drives are available in various storage capacities are 4GB,16GB Up to 1TB.They are widely used as an easy and small medium to transfer and store the information from the computer.

Pen drive is a portable Universal Serial Bus (USB) flash memory device for storing and transferring audio, video, and data files from a computer system to another devices. Every computer or laptop has a USB port, and the pen drive is compatible with the operating system in a computer, it is easy to move or copy the data from the hard drive of the computer to another device and to another computer in a few minutes.

Pen drive is a small device that is easy to carry. It is useful USB flash drive and it stores various types of data files that you can use in your computer system and other devices.

pen drive

How to transfer files in Pen drive(USB Flash Drive):-

A pen drive plugged into a USB port can be used as an interface device to transfer files, documents and photos to a PC.

Similarly, select files can be transferred from a pen drive to any workstation.

A pen drive is a portable Universal Serial Bus (USB) flash memory device for storing and transferring audio, video, and data files from a computer. As long as the desktop or laptop has a USB port, and the pen drive is compatible with the operating system, it should be easy to move the data from the hard drive to the device — and to another computer . The drive gets its name from the fact that many have a retractable port connector like a ballpoint pen, and they are small enough to fit into a pocket. Other names include flash drive, jump drive, and thumb drive.

We use Pendrive for a long time, so we share data, we take data, we use it by putting it in a computer or mobile phone. A lot of our work is also done from Pen drive, you guys check a lot of work quickly, finish, pen drive is very beneficial and useful for ourselves. pen drive is a computer system where store data retrieved data wherever we want. Computer system is very beneficial for us, from where we can do a lot of work in 1 day, there are many advantages in computer as far as it works to store data for you. We do a lot of work very quickly with the help of computer, in pen drive we store data, we also take it out soon, we can use pen drive when it is very useful for us. Pen drive is very useful for us it is used to store the data attribute data and used to store multiple file in a pen drive. Pen drive is definitely a good portable device to use and we can explore and retrieve data in the pen drive

How To use a Pen Drive :-

Using a pen drive is easy: you can simply insert the pen drive into computer or laptop via USB port, which is equipped with a USB connector. When you plug the pen drive into the computer system it automatically activates the pen drive. Once your pen drive is active, you can drag and drop files or copy and move the files into the memory. This process is not difficult, you can attach your pen drive to your system and then you work with it. There are different types of computer operating systems which we use today, so manufacturers configure their pen drives to work with a variety of operating systems. Before buying any portable storage device, a consumer should read the packaging carefully to make sure that it will work with his or her computer system.

Memory Cards:-

What is memory card and uses of memory card:-

These are the data storage device in a chip shaped which can store the data in it. They are commonly used in many electronic devices, including cameras, mobile phones, laptop, and computers. You will get to see memory card starting from 16GB and its maximum capacity goes to 1TB, above this you will also get memory card like 2 terabyte in memory card but its price will be very high will be expensive.

They are small re-recordable, easily portable and very light-weighted.

A memory card is a type of storage device that is used for storing data files.

Memory cards provides a permanent and non-volatile medium to store data and files from the attached device. Memory cards are commonly used in small, portable devices, such as cameras and phones.

A memory card is also known as a flash card.

A memory card is mainly used as a primary and portable flash memory in mobile phones, cameras and other portable and handheld devices. Besides providing non-volatile media storage, a memory card also uses solid state media technology.

We use memory card in many places like mobile phone laptop computer, we use memory card all over the place. Memory card is very beneficial thing for us. Can't remove a lot of data in SIM. There are many different types of memory cards in the market and memory card you get Samsung, Kingstone of all branch memory card we use in our mobile so that we can install our more data and make memories.

The speed of the memory card is very fast, due to which we are able to store the data quickly, more people can remove the data from it, you will find the memory card everywhere, see if we do laptop computer to take you away. We use memory card so that whatever data we have, we can keep it safe in one place and later use it in future. Memory card is very effective for us. With memory card, we can do a lot of work quickly. Memory card is a very beneficial device for us, there is a system that we get. Pen drive memory card both are different, pen drive is a system in which you get allocated space, the same thing in memory card, the difference is that we use pen drive such internal storage and memory card is external. We have been using the memory card for a long time, saying it is very beneficial for us, the price of the memory card is 500-600 in which you will get a 32GB memory card.

Some of the most popular forms of memory cards are:

1.Secure Digital (SD) card

2.CompactFlash (CF) card

3.SmartMedia

4.Memory Stick

5.MultiMediaCard (MMC)

What is Internet?

Internet has gained a popularity and emerged as an efficient means of communication in today's world. The idea of introducing the Internet was to allow billions of people to share information and ideas like audio, video, images etc. across the world. The Internet is a world wide network of networked computers those are able to exchange information with each other.

Internet, a system architecture that has revolutionized communications and methods of commerce by allowing various computer networks around the world to interconnect.

By 2020, approximately 4.5 billion people, or more than half of the world’s population, were estimated to have access to the Internet.

Internet:-

Internet stands for International Network, which began in 1950s by Vint Cerf known as the Father of Internet. Internet is a 'network of networks' that consists of millions of public and private networks of local and global scope. Basically network is a group of two or more computer system linked together

The Internet is a vast network that connects computers all over the world.

With Internet people can share information and communicate from anywhere with an Internet connection..

History of Internet:-

In 1969 , the University of California at Los Angeles, the University of Utah were connected as the beginning of the ARPANET(Advanced Research Projects Agency Network) using 50 Kbits circuits. It was the world's first operational packet switching network. The goal of this project was to connect computers at different Universities and U.S. defense.

In mid 80s another federal agency the National Science Foundation , created a new high capacity network called NSF net, which was more capable than ARPANET. The only drawbacks of NSF net was that it allowed only the academic research on its network and not any kind of private business on it. So, private organization and people started working to build their own networks, which were later interconnected with ARPANET and NSF net to form the Internet.

internet

Advantages of Internet:-

The advantages of Internet are as follows:-

i. Internet enables one to connect anyone in the Internet.

ii. Internet allows you to easily communicate with other people.

iii. On Internet you can publish documents that saves on the Internet.

iv. A valuable resource for companies to advertise and conduct business.

v. Greater access to information reduces the research time.

Disadvantages of Internet:-

The disadvantages of Internet are as follows:-

i. Internet is a major source of computer viruses.

ii. Much of the information is not checked and may be incorrect or irrelevant.

iii. Cyber frauds may take place involving Credit/Debit cards numbers and details.

iv. The messages sent across the Internet can be easily accessible.

How Internet connects?

The Bandwidth and cost are the two factors that help you in deciding which Internet connections is to use. The speed of Internet access depends on the bandwidth.
The Internet is a vast collection of networks that connect to each other. Computers connect to each other within networks and these networks also all connect with each other, one computer can talk to another computer in a faraway network thanks to the Internet. Internet makes possible to rapidly exchange the information between computers across the world.
Computers connect to the Internet via wires, cables, radio waves, and other types of networking infrastructure. All data sent over the Internet is converted into pulses of light or electricity, also called "bits," and then interpreted by the receiving computer. The more bits that can pass over these wires and cables at once, the faster the Internet works.
Some of the Internet connections available for Internet access are as follows:-
1.Dial-Up Connection:-
A Dial-up is a method of connecting to the Internet using an existing telephone line to connect to the Internet. When a user initiates a dial-up connection, the modem dials a phone number of an Internet Service Provider (ISP) that is designated to receive dial-up calls. The ISP then establishes the connection which usually taken about ten seconds and is accompanied by several beeping and buzzing sounds.

2.Broadband Connection:-
The term broadband commonly refers to the high speed Internet access that is always on and faster than the traditional dial-up access line.. It uses a telephone line to connect to the Internet. Broadband access allows users to connect to the Internet at a greater high speed than a standard 256KB modem or dial-up access.
Broadband includes several high speed transmission technologies are as follows:-
Cable Modem:-
This service enables cable operators to provide broadband using the same co-axial cables that deliver pictures and sound to your TV set. Most cable modems are external devices that have two connections, one is connected to the cable outlet and the other is connected to a computer. They provide transmission speed of 1Mbps or more.

Digital Subscriber Line(DSL):-
It is a popular broadband connection. It provides Internet access by transmitting digital data over the wires of a local telephone network. DSL is the most common type of broadband service. It uses the existing copper telephone lines.

Broadband over Power Line(BPL):-
BPL is a the delivery of broadband over the existing low and medium voltage electric power distribution network. BPL is good for areas, where there are no other connections but power infrastructure exists.
e.g. Rural areas etc.

Wireless Connection:-

The wireless broadband connects a home or business to the Internet using a radio link between the customer's location and and the service providers facility. wireless broadband mobile can be fixed. Unlike DSL and cable wireless wireless broadband requires neither a modem nor a cable. It can be easily established in areas, where it is not feasible to deploy DSL or cable.

Some ways to connect the Internet wirelessly are as follows.

1. Wireless Fidelity (Wi-Fi):-
Wireless fidelity is a universal wireless networking technology that utilises radio frequencies to transfer data. Wi-Fi allows high speed Internet connection out the use of cables or wires. Wi-Fi networks can be use for Public Internet access at "Hotspot" such as restaurants, coffee shops, hotels, airports, convention centers and city parks.

2.Worldwide Interoperability for Microwave Access (Wi-MAX):-
It is one of the hottest broadband wireless technologies around today. Wi-Max systems are expected to deliver broadband access services to residential and enterprise customers in an economical way.

Wi-Max has the ability to provide service even in areas that are difficult for wired infrastructure to reach and the ability to overcome the physical limitation of traditional wired infrastructure.

3.Mobile Wireless Broadband Service:-
These services are also becoming available from mobile telephone service providers and others. These services are generally appropriate for mobile customers and require a special PC card with a built-in antenna that plugs into a user computer.
Generally, they provide lower speeds in the range of several hundred kbps.

a. What is Intranet?
Ans:- Intranet is a private network for internet for Internet tools, but available within an organization. In large organization, Intranet allows an easy access to corporate information for employees.

b. What is Podcast?
Podcast is program either talk numeric that is made available in digital format for automatic download over the Internet.

c. What Extranet?
It is a is a private network that uses the Internet protocol and the public telecommunication system to security share part of a business information.

Q. What is the full form of INTERNET?

Ans. The full form of Internet is Interconnected Network that is a network system that connects millions of Web servers.

Q .Difference between WWW and Internet?

Ans. The world wide web is a way of exchanging information between various computers on the Internet.

While Internet, a system architecture that has revolutionized communications and methods of commerce by allowing various computer networks around the world to interconnect.

The Internet is a connection between computers and other devices that form a huge network of systems.

Introduction to World Wide Web(WWW):-

WWW was introduced on 13th March 1989. The world wide web is a system of Internet servers that supports hypertext and multimedia to access to several Internet protocols on a single interface.

The world wide web is often abbreviated as the Web or WWW. The world wide web is a way of exchanging information between various computers on the Internet.

Web Page:-

Web page is the backbone of the world wide web is made up of files called pages or web pages, containing information and links to resources- both text and multimedia throughout the Internet. It is created using HTML. There are basically main two types of web pages as follows

i. Static Webpage

ii. Dynamic Webpage.

The main or first page of a website is called home page.

Website: -

Website is what a group of web pages that follow the same theme and are connected with each other with hyperlinks is known as Website. In other words " A website is a collection of digital documents which are made up of HTML files that are linked together and that exists on the web under the same domain.

e.g. http://www.google.com is a website while

http://www.car.com/new/ is a Webpage.

Web Browser:-

Web browser is a software application that is used to locate, retrieve ,and display the content on the world wide web including Web pages. Web browsers are programs used to explore the Internet. We can install more than one Web browser on a single computer. The user can navigate through files, folders and Websites with the help of a browser.

There are two types of Web browsers as following:-

1. Text Web Browser:-

A web browser that displays only text based content or information is called |Text Web browser.

e.g. Lynx, which provides access to the Internet in the text mode only.

2. Graphical Web Browser:-

A web browser that supports both text and graphic information is called Graphical Web browser.

e.g. Internet Explorer, Firefox, Safari and Google Chrome.

Note:

The first graphical web browser was NCSA Mosaic.

Web Server:-

A Web browser is a client that requests HTML files from web servers. The server computer will deliver those web pages to the computers that request them and may also do other processing with the web pages. Every Web server that is connected to the Internet is given a unique address, i.e. IP address made up of series of four numbers between 0 to 255 separated by periods.

e.g. Apache HTTP Server, Internet Information Services(IIS) etc.

Some other article related to Internet:-

Q. What is Web Address and URL?

Ans. A Web address identifies the location of a specific Web page on the Internet, such as

https://www.techenthuz.com. On the Web, Web addresses are called URLs(Uniform Resource Locator).

It is the web address for a Website or Web page. Tim Berners Lee created the first URL in 1991 to allow the publishing of hyperlinks on the world wide web.

e.g. "http://www.google.com/services/index.html"

http:// - Protocol identifier

www - World Wide Web

google.com - Domain name

/services/ - Directory

index.html - Web page

Definition of Interconnecting Protocols:-

A protocol is a set of rules that govern data communications. A protocol defines what is communicated, how it is communicated and when it is communicated.

The Internet Protocol (IP) is a protocol is used for routing and addressing packets of data so that they can travel across networks and arrive at the correct destination.

Data traversing the Internet is divided into smaller pieces, called packets. IP information is attached to each packet,

and this information helps routers to send packets to the right place. Every device or domain that connects to the Internet is assigned an IP address, and as packets are directed to the IP address attached to them, data arrives where it is needed.

Generally some of protocols used to communicate via an Internet are as follows:-

1. Transmission Control Protocol/Internet Protocol(TCP/IP):-

The details of TCP protocols are as follows:

a. Transmission Control Protocol(TCP):-

It provides reliable transport service, i.e. it ensures that message sent from sender to receiver is properly routed. TCP converts messages into a set of packets at the source which are then reassembled back into messages at the destination.

b. Internet Protocol(IP):-

Internet protocol allows different computers to communicate by creating a network of networks. IP handles the dispatch of packets over the network. It maintains the addressing of packets with multiple standards. Each IP packet must contain the source and the destination addresses.

Note:-

A IP address is a 32 bit number.

2.Hyper Text Transfer Protocol(HTTP):-

It defines how messages are formatted and transmitted and what actions should be taken by the Web Servers and browsers in response to various commands.

3.File transfer Protocols(FTP):-

File transfer protocol can transfer files between any computers that have an Internet connections and also works between computers using totally different operating systems.

Some examples of File Transfer Protocol software are FileZilla, gFTP, Konqueror, etc.

4.Telnet Protocol(TP):-

It is a program that runs on the computer and connects PC to a server on the network. The protocol used on the Internet or Local Area Network. Telnet session will started by entering valid username and password.

5.Point-to-Point Protocol(PPP):-

Point-to-Point protocol is a dial account which puts your computer directly on the Internet. A modem is required for such connection which transmits the data 9600 bits per second.

6.Usenet Protocol:-

The Usenet service allows a group of Internet users to exchange their views and information on some common topic that is of interest to all the members belonging to that same group.

Several such groups exist on the Internet are called newsgroups. Usenet has no central server or administration.

7.Simple Mail Transfer Protocol(SMTP):-

It is the standard protocol for Email services on a TCP/IP network. It provides the ability to send and receive E-mail messages.

8.Voice Over Internet Protocol(VoIP):-

VoIP allows delivery of voice communication over 'IP' Internet Protocol networks.

e.g. IP calls etc.

9.Wireless Application Protocol(WAP):-

A wireless application protocol browser is a commonly used Web browser for small mobile devices such as cell phones.

Other Topics related to:-

Q. What is HTML?

Ans- It stands for Hyper Text Markup Language. HTML is used for designing Web pages. A markup language is a set of markup(angular bracket < >) tags which tells the Web browser how to display a web page word's and images for the user. Each individual markup code is referred to as an element or tag.

Computer Architecture:-

The computer architecture deals with the functional behavior of a computer system as viewed by a programmer. It can also be described as the logical structure of the system unit that housed electronic components. The computer architecture forms the backbone for building successful computer systems. the first computer architecture was introduced in 1970.

Components of Computer:-

A computer consists of following three main components:-

1.Input/Output(I/O Unit)

2.Central Processing Unit(CPU)

3.Memory Unit

Note:-

System unit is a metal or plastic case that holds all the physical parts of the computer.

The components that process data are located in it.

1.Input Unit:-

The computer accepts coded information through input unit by the user. It is a device that is used to give required information to the computer.

e.g. Keyboard, mouse etc.

An input units perform the following functions:-

i. It converts these instructions and data in the computer in acceptable format.

ii. It accepts the instructions and data from the user.

iii. It supplies the converted instructions and data to the computer system for further processing.

2.Output Unit:-

This unit sends the processed results to the user. It is mainly used to display the desired result to the user as per input instruction.

e.g. Monitor, printer etc.

An output units perform the following functions:-

i. It converts these coded results to human acceptable format.

ii. It accepts the result produced by the computer which are in coded form and hence cannot be easily understood by the user.

iii. It supplies the converted results to the user.

3.Central Processing Unit:-

It consists of a set of registers, arithmetic logic unit and controls unit, which together interpret and execute instructions in assembly language.

The primary functions of the CPU are as follows:-

i. The CPU transfers instructions and input data from main memory to registers, i.e. internal memory.

ii. The CPU executes the instructions in the stored sequence.

iii. When necessary , CPU transfers output data from registers to main memory.

Central Processing Unit is often called the brain of the computer system. The CPU is fabricated as a single Integrated Circuit (IC) and it is also known as microprocessor.

A CPU controls all the internal and external devices and performs arithmetic and logic operations.

computer architecture

The CPU consists of following main components:-

Arithmetic Logic Unit:- ALU contains the electronic circuitry that executes all arithmetic and logical operations on the available data. It uses registers to hold the data that is being processed.

Most ALU performs the following operations in a computer:-

i. Logical operations(AND, NOT, OR, XOR etc.)

ii. Comparison operator (=, <, >, >=, <= etc.)

iii. Arithmetic operations such as addition, subtraction, multiplication, division etc.

Note:-

Registers:- Registers are used to quickly accepts , store, transfer data and instructions that are being used immediately by the CPU. These registers are the top of the memory hierarchy and are the fastest way for the system to manipulate data. The number and size of registers vary from processors to processors.

Control Unit:- Control Unit coordinates with the input and output devices of a computer. It directs the computer to carry out stored program instructions by communicating with the ALU and the registers. The basic functions of control unit is to fetch the instructions stored in the main memory, identify the operations and the devices involved in it and accordingly generate control signal's. It organises the processing of data and instructions.

Memory Unit:- Memory unit is responsible to store programs or data on a temporary or permanent basis. It has a primary memory which is called main memory and secondary memory is also called auxiliary memory. The input data which is to be processed is brought into the main memory of a computer system before processing

Another kind of memory is referred to as secondary memory of a computer. This unit does not deal directly with the CPU in a computer system. This unit is used to permanently store data and programs in the form of output in the computer system.

What is Motherboard:-

The main circuit board contained in any computer system is called motherboard. Motherboard is also known as the main board or logic board or system board. All the electronic devices and circuits of computer systems are attached to this board like CPU, ROM, RAM, expansion slots, PCI slots and USB ports. It also includes controllers for devices like DVD drive, hard drive, mouse and keyboard etc. In some other words, motherboard makes everything in a computers system work together.

A motherboard is one of the most essential parts of a computer system.

It is the brain of the computer system. It holds together many of the crucial components of a computer, including the central processing unit (CPU), memory and connectors for input and output devices. Thin layers of copper or aluminum foil, referred to as traces, are printed onto this sheet. These traces are very narrow and form the circuits between the various components.

A motherboard contains a number of sockets and slots to connect the other components.

Components of Motherboard:-

The various components of motherboard are as follows:-

i. CMOS Battery

ii. Fan

iii. BIOS Chip

iv. Processor Chip

v. Buses

vi. SMPS

vii. Expansion Slot

viii. PCI Slot

Interconnection of Units in a Computer system:-

In a computer system the CPU sends the data or instructions and information to the components inside the computer as well as to the peripheral devices attached to it. A Bus is a s set of wires used for interconnection where each wire can carry one bit of data.

In other words bus is a set of electronic signal pathways that allows information and signals to travel between components inside or outside of a computer.

A Bus can be divided into two types:

1.Internal Bus:

This bus connects components inside the motherboard like CPU and system memory. Internal bus is also called system bus.

System bus includes the following buses:-

i. The command to access the memory or the I/O devices is carried by the control bus.

ii. The address of I/O devices or memory is carried by the address bus. The data to be transferred is carried by the data bus.

2.External Bus:-

It connects the different external devices like peripherals, expansion slots and I/O ports. External bus is also called expansion bus.

Instruction Cycle:-

Instruction cycle represents the sequence of events that takes place as an instructions is read from memory and executed.

Diagram of Instruction Cycle

Fetch => Decode => Execute => Store

A simple instruction cycle consists of the following steps:-

1.Fetching:- It fetch the information from the memory.

2.Decoding:- It decodes the instruction for operation.

3.Executing:- It executes the instructions.

4.Storing:- It also stores the data in the memory.

Instruction Format:-

In computer system, computers understands instructions only in terms of 0 and 1, which is called the machine language. A computer program is a set of instructions that describe the steps to be performed for carrying out a computational task. The processor must have two inputs: instructions and data. The instructions tell the processor to what actions are needed to perform this task. An instructions is further divided into two parts: i. Operation(OP Code) and ii. Operand.

Notes:-

Sockets' are the connecting points of chip on the motherboard.

Pipelining:- It improves the execution speed by putting the execution steps of several instructions into parallel.
Machine Cycle:- It is defined by the time, that takes to fetch two operands from registers and performs ALU operation and stores the result in a register of a computer system.

Some useful terms related to to computer architecture:-

Q. What is UPS(Uninterruptable Power Supply):-

Ans. It is an electrical device that provides emergency power to a load when the input power source or main power source fails.

Q. What is DMA(Direct Memory Access):-

Ans. It is a method that allows an I/O devices to send or receive data to or from the main memory.

The speed of processor is measured in millions of cycles per second or Megahertz(Mhz) by clock speed.

An uniform interval of CPU time allocated for use in performing a task is called time slice.

Q. What is Buffer:-

Ans. It is a temporary storage where register holds the data for future execution.

Q. What is Accumulator:-

Ans. It is a register in a CPU which intermediate arithmetic and logic results that are stored.

What are Some solutions to Computer Security:-

Cybersecurity protects data which we save on the internet.

The data we save on the internet could be our online banking information, medical or financial information, even our private photographs.

There are many challenges that come with access to the internet.

Some safeguards(or solutions) to protect a computer system from accidental damage are described as follows:-

1.Antivirus Software:-

Antivirus is an application software that is used to scan the computer system from an unwanted virus. It is software that is designed to prevent, search for , remove and detect viruses and other malicious software like trojans etc. It consists of computer programs that attempt to identify threats and eliminate computer viruses and other malwares.

anti virus

Some popular antiviruses are follows:-

i. Avg

ii. K7

iii. McAfee

iv. Kaspersky

v. Quick Heal

vi. Norton

vii. Avast etc.

Digital Certificate:-

Digital certificate is the attachment to an electronic message used for security purposes. It provides a means of providing your identity in electronic transactions. The common use of a digital certificate is to verify that a user sending a message is who he or she claims to be, and to provide the receiver with the means to encode a reply.

Password:-

Password is a secret word of characters used for user authentication to prove identity or access approval to gain access to a resource.

A password is typically somewhere between 4-16 characters long. It depends on how the computer system is setup. When a password is entered into a computer system, the computer system is careful not to display screen, in case others might see it.

There are two common modes of a computer password are as follows:-

1.Strong Password :- It is difficult to break. It is a combination of symbols and alphabets.

2.Weak Password:- It is easily to remember and easily to break it.

Firewall:-

Firewall is a software based on hardware and it is used to help in keeping a network secure. It's primary objective is to control the computer from incoming or outgoing network traffic by analysing the data packets and determine whether it should be allowed through it or not, based on a predetermined rule set.

A network firewall builds a bridge between an internal network that is assumed to be secure and trusted. A firewall also includes a proxy server that makes network requests on behalf of workstation users.

File Access Permission:-

Most of the file systems have methods of assigning access or permissions rights to specific user and group of users. These system controls the ability of the users to view or make changes to the contents of the file system. File access permission refers to privileges that allow a user to read write and exex=cute files in a computer system.

There are three file access permissions as follows:-

1.Write Permission:-

If you have write permission, you can only modify or remove the contents of the file. In case of directory you can add or delete contents to the files of the directory.

2.Read Permission:-

If you have read permission, you can only see the contents of the file. In case of directory access means the user can read the contents of the file in a computer system.

3.Execute Permission:-

If you have execute permission of a file in a computer system , you can only execute a file. In case of directory you must have execute access to the bin directory on order to execute it or cd commands.

Tips-Tricks:-

The legal right to use software based on specific restriction's is granted via Software license.
Payloads is code in the worm designed to do more than spread the worm . Bomb virus has a delayed payload.
Software privacy means copying of data or computer software without the owner's permission to access it.
Keylogger:- It a software program designed to record every keystroke on the machine on which it runs.

Read about the threats to computer security:

Read different types of virus:

click here:-

Definition Of Computer Security :-

Let's understand first what is computer security:-

Computer security is also known as cyber security. Computer security is a branch of information technology known as information security which is intended to protect computers. It is the protection of computing systems and the data that they store or access.

Computer security is the protection of computer systems and information from harm, theft, and unauthorized use. Computer hardware is typically protected by the same means used to protect other valuable or sensitive equipment, namely, serial numbers, doors and locks, and alarms.

Methods to Provide Protection:-

There are four primary methods to provide protection:-

1.System Access Control:-

It ensures that unauthorised users do not get into the system by encouraging authorised users to be security conscious.

2.Data Access Control:-

It monitors who can access the data, and for what purpose. Your system might support mandatory access controls with these. The system determines access rules based on the security levels of the people, the files and the other objects in your system.

3.System and Security Administration:-

It performs offline procedures that makes or break secure system.

4.System Design:-

It takes advantages of basic hardware and software security characteristics.

computer virus

Components of Computer Security:-

Computer security is associated with many core areas.

Basic components of computer security system are as follows:-

1.Confidentialy:-

It ensures that data is not accessed by any unauthorised person.

2.Integrity:-

It ensures that information is not altered by any unauthorised person in such a way that it is not detectable by authorised users.

3.Authentication:-

It ensures that users are the persons they claim to be.

4.Access Control:-

It ensures that users access only those resources that they are allowed to access.

5.Non-Repudiation:-

It ensures that originators of messages cannot deny they are not sender of the message.

6.Availability:-

It ensures that systems work promptly and service is not denied to authorised users.

7.Privacy:-

It ensures that individual has the right to use information and allows another to use that information.

8.Stenography:-

It is an art of hiding the existence of a message. It aids confidentially and integrity of the data.

9.Cryptography:-

It is the science of writing information in a 'hidden' or 'secret' form and an ancient art. It protects the data in transmit and also the data stored on the disk.

Some terms commonly used in cryptography are as follows:-

i. Plain Text:- It is the original message that is an input.

ii. Cipher:- It is a bit-by-bit or character transformation without regard to the meaning of the messages.

iii. Cipher Text:- It is the coded message or the encrypted data.

iv. Encryption:- It is the process of converting plain text to cipher text, using an encryption algorithm.

v. Decryption:- It is the reverse of encryption, i.e. converting cipher text to plain text.

Sources of Cyber Attack:-

The most potent and vulnerable threat of computer users is virus attacks. a computer virus is a small software program that spreads from one computer to another computer and that interferes with computer operation. It is imperative for every computers users to be aware about the software and its program that can help to protect the personal computers from attacks.

The sources of attack can be follow:-

1.Downloadable Programs:-

Downloadable files are one of the best possible sources of virus. Any text of executable like games, screen saver are one of the major sources. If you want to download programs from the Internet then it is necessary to scan every program before downloading them.

2.Cracked Software:-

These software are another source of virus attacks. Such cracked forms of illegal files contain virus and bugs that are difficult to detect as well as to remove.

Hence, it is always a preferable option to download software from the appropriate source.

3.E-mail Attachments:-

These attachments are the most common sources of viruses. You must handle E-mail attachments with extreme care, especially if the E-mail comes from an unknown sender.

4.Internet:-

Majority of all computer users are unaware as when viruses attack computer system. Almost all computer users click or download everything that comes their way and hence unknowingly invites the possibility of virus attacks.

5.Booting from an Unknown CD:-

When the computer system is not working, it is good practice to remove the CD. If you do not remove the CD, it may start to boot automatically from the disk which enhances the possibility of virus attacks.

Lets understand what is Malware?

Malware stands for malicious software. It is a broad term that refers to a variety of malicious programs that are used to damage computer system, gather sensitive information or gain access to private computer systems. It includes computer viruses, worms, trojan horses, rootkits, spyware, adware.

Malware is the collective name for a number of malicious software variants, including viruses, ransomware and spyware. Shorthand for malicious software, malware typically consists of code developed by cyber attackers, designed to cause extensive damage to data and systems or to gain unauthorized access to a network.

Some of them are described below:-

Virus:-

VIRUS stands for Vital Information Resources Under Siege. Computer viruses or perverse software's are small programs that can negatively affects the computer. It obtains control of a PC and directs it to perform unusual and often destructive actions. Viruses are copied itself and programs which further spread the infection. The virus can affect or attack any part of the computer software such as the boot block, operating system, system areas, files and application programs. The first computer virus Creeper created in 1971.

Types Of Virus:-

Some common types of viruses are as follows:-

1.Resident Virus:- It fixes themselves into the system's memory and get activated whenever the operating system runs and infects all the files that are opened. It hides in the RAM and stays there even after the malicious code is executed.

e.g. Randex, Meve etc.

2.Direct Action Virus:- It comes into action when the file containing the virus is executed. It infects files in the folder that are specified in the AUTOEXEC.bat file path.

e.g. Vienna virus etc.

3.Overwrite Virus:- It deletes the information contained in the files that it infects , rendering them partially or totally useless, once they have been infected.

e.g. Way, Trj.Reboot etc.

4.Boot Sector Virus:- It is also called Master Boot Sector virus or Master Boot Record virus. This type of virus attack the boot sector of a hard disk. Brain was the first PC boot sector virus created in 1986.

e.g. Polyboot.B, AntiEXE etc.

5.Macro Virus:- It infects file that are created using certain applications or programs that contain macros like .doc, .xls, .ppt etc.

6.File System Virus:- It is also called Cluster virus or Directory virus. It infects the directory of the computer by changing the path that indicates the location of the file.

e.g. Dir-2 virus etc.

7.Polymorphic Virus:- It encrypts or encodes itself in a encrypted way , every time it infects a system. This virus then goes on to create a large number of copies.

e.g. Elkern, tuareg etc.

8.FAT Virus:- It is used to store all the information about the location of files, unusable space, etc

e.g. Link virus etc.

9.Multipartite Virus:- It may spread in multiple ways such as the operating system installed or the existence of certain files.

e.g. Flip etc.

10.Web Scripting Virus:- Many websites execute complex code in order to provide interesting content. These sites are sometimes created with with purposely infected code.

e.g. JS Fortnight etc.

Some common viruses are tabulated below:-

Year Name

1971 Creeper

1982 Elk Cloner

1988 The Morris Internet Worm

1999 Melissa

2000 I Love You

2001 Code Red

2003 SQL Slammer

2003 Blaster

2004 Sasser

2010 Stuxnet

2011 Trojan

2012 Rootkit

2014 Generic PUP

2014 Net Worm

Network Topology:

Let's understand what is network topology?

The term 'topology' refers to the way a network is laid out ,either physically or logically. Topology can be referred as the geometric arrangement of a computer system. Each computer system in a topology is known as node.

Network topology refers to the links and nodes of a network are arranged to relate to each other.

Logical network topology examples include twisted pair Ethernet, which is categorized as a logical bus topology, and token ring, which is categorized as a logical ring topology.

Physical network topology like star, mesh, tree, ring, point-to-point, circular, hybrid, and bus topology

networks, each consisting of different configurations of nodes and links. The ideal network topology depends on each business’s size, scale, goals, and budget. A network topology diagram helps visualize the communicating devices, which are modeled as nodes, and the connections between the devices, which are modeled as links between the nodes. Topologies are categorized as either physical network topology, which is the physical signal transmission medium, or logical network topology, which refers to the manner in which data travels through the network between devices, independent of physical connection of the devices.

network topology

The most commonly used topology are described below:-

1.BusTopology:-

It is such that there is a single line to which all nodes are connected. It is usually used when a network installation is small, simple or temporary. In Bus topology, all the network components are connected with the same(single) line.

Advantages of Bus Topology:-

1.It is cost effective.

2.Cable required is least compared to other network topology.

3.It is used in small networks.

4.It is easy to understand.

5.Easy to expand joining two cables together.

Disadvantages of Bus Topology:-

1.Cables fails then whole network fails.

2.If network traffic is heavy or nodes are more the performance of the network decreases.

3The cable has a limited length.

2.Star Topology:-

In Star topology network , the peripheral nodes are connected to a central node, which rebroadcasts all transmissions received from any peripheral node to all peripheral nodes across the network. A star network can be expanded by placing another star hub.

Advantages of Star Topology:

1.Fast performance with few nodes and low network traffic.

2.Hub can be upgraded easily.

3.Easy to troubleshoot.

4.Easy to setup and modify.

Disadvantages of Star Topology:-

1.Cost of installation is high.

2.It is expensive to use.

3.If the hub fails then the whole network is stopped because all the nodes depend on the hub.

Performance is based on the hub that is it depends on its capacity

3.Ring or Circular Topology:-

This topology is used in high-performance networks where large bandwidth is necessary. The protocols used to implement ring topology are Token Ring and Fiber Distributed Data Interface(FDDI). In ring topology, data is transmitted in the form of Token over a network.

Advantages of Ring Topology:-

1.Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.

2.Cheap to install and expand

Disadvantages of Ring Topology:-

1.Troubleshooting is difficult in ring topology.

2.Adding or deleting the computers disturbs the network activity.

3.Failure of one system disturbs the whole network.

4.Mesh Topology:-

Mesh topology is also known as completely interconnected topology. In mesh topology, every node has a dedicated point-to-point link to every other node.

There are two ways to transmit data over the Mesh topology, they are :

Routing
Flooding
Advantages of Mesh Topology:-

1.Each connection can carry its own data load.

2.It is robust.

3.In this topology the fault is diagnosed easily.

4.It provides security and privacy.

Disadvantages of Mesh Topology:-

1.Installation and configuration is difficult.

2.Cabling cost is more.

5.Tree Topology:-

This is network topology in which nodes are arranged as a tree. The function of the central node in this topology may be distributed, It's basic structure is like an inverted tree, where the root acts as a server. It allows more devices to be attached to a single hub.

Advantages of Tree Topology:-

1.Extension of bus and star topologies.

2.Expansion of nodes is possible and easy.

3.Easily managed and maintained.

4.Error detection is easily done.

Disadvantages of Tree Topology:-

1.It is heavily cabled.

2.Very Costly.

Models Of Computer Networking:-

There are mainly two models of computer networking as follows:-

1.Peer-to-Peer Network:-

It is also known as P2P network. This computer network relies on computing power at the edges of a connection rather than in the network itself. P2P network is used for sharing content like audio, video, data or anything in digital format.

In P2P connection, a couple of computers is connected via Universal Serial Bus(USB) to transfer files. In peer-to-peer networking, each or every computer may be worked as a server or client.

2.Client-Server Network:-

The model of interaction between two application programs in which a program at one end(client) requests a service from a program at the other end(server).

It is a network architecture which separates the client from the server. It is scalable architecture, where one computer works as a server and other as client. Here, client acts as the active device and server behaves as passively.

Notes:-

Multi-access network topology, also known as a non-broadcast multiple access network (NBMA),

consists of multiple linked hosts in which data is transferred directly from one computer to another single host across a switched fabric or over a virtual circuit.

Smart grid network topology refers to the network configurations that are necessary to facilitate system operations in a smart grid. A smart grid is an electrical network of smart meters, smart appliances, renewable energy resources, and energy efficient resources that condition and control the production and distribution of electricity.

OSI Model:-

It stands for Open System Interconnection(OSI). OSI is a standard reference model for communication between two end users in a network. In 1983, the International Standard Organization(ISO) published a document called Basic Reference Model for Open System Interconnection, which visualizes network protocols as a seven layered model.

OSI is a layered framework for the design of network system that allows communication between all types of computer system. It is mainly consists of seven layers across a network.

The Open Systems Interconnection (OSI) model describes seven layers that computer systems use to communicate over a network. It was the first standard model for network communications, adopted by all major computer and telecommunication companies in the early 1980s

The modern Internet is not based on OSI, but on the simpler TCP/IP model.

OSI was introduced in 1983 by representatives of the major computer and telecom companies,

and was adopted by ISO as an international standard in 1984.

There are Seven Layers in OSI Model as follows:-

1.Application Layer(User Interface):-

The retransferring of files of information, login, password checking, packet filtering, etc.

2.Presentation Layer(Data Formatting):-

It works as a translating layer , i.e. encryption or decryption.

3.Session Layer(Establish and Maintain connection):-

To manage and synchronize conversation between two systems. It controls logging ON and OFF, user identification, billing and session management.

4.Transport Layer(Transmission Control Protocol(TCP) accurate data):-

It decides whether transmission should be parallel or single path , multiplexing splitting or segmenting the data, to break data into smaller units for efficient handling, packet filtering.

5.Network Layer(Internet Protocols(IP) routers):-

The routing of the signals, divide the outgoing messages into packets, to acts as a network controller for routing data.

6.Data Link Layer(Media Access Control(MAC) switches:-

Synchronization , error detection and correction. To assemble outgoing messages into frames.

7.Physical Layer(Signals-cables or operated by repeater):-

It Makes and break connections , define data voltages ⚡and data rates, convert data bits into electrical signal. Decide whether transmission is simplex, half-duplex or full-duplex.

In OSI model, physical layer is the lowest layer which is implemented on both hardware and software and application layer is the highest layer.

Some other terms related to Network:-

Q. What is Multiplexing?

Ans. It is a technique used for transmitting signals simultaneously over a common medium. It involves single path and multiple channels for data communication.

Q. What is Code Division Multiple Access( CDMA):-

Ans. It is a channel access method used by various radio communication technologies. CDMA employs spread spectrum technology and a special coding scheme, where each transmitter is assigned a code to allow multiple users to be multiplexed over the same physical channel.

Q. What is Packet Switching:-

Ans. It refers to the method of digital networking communication that combined all transmitted data regardless of content, type or structure into suitable sized blocks, known as packets.

Q. What is Public Switched Telephone Network(PSTN):-

It is designed for telephone which requires modem for data communication. It is used for FAX machine also.

Q. What is Integrated Service Digital Networking(ISDN):-

It is used for voice, video and data services. It uses digital transmission and combines both circuit and packet switching.

Q. What is Ethernet:-

It is widely used technology employing a bus technology. An ethernet LAN consists of a single co-axial cable called Ether. It operates at 10Mbps and provides a 48-bits address. Fast ethernet operates at 100Mbps.

Q. What is Token:-

It is small message used to pass between one station to another station.

Network Devices:-

Let's understand what is network devices?

The network devices are required to amplify the signal to restore the original strength of signal and to provide an interface to connect multiple computers in a network. There are many types of network devices used in networking.

The devices which are used for communication between different hardware’s used in the computer network are called network devices.

These devices are also known as physical devices, networking hardware, and

computer networking devices. In a computer network, each network device plays a key role based on their functionality, and also works for different purposes at different segments.

Types of Network Devices:-

There are different types of network devices used in a computer network as follows:-

Repeater
Network Hub
Gateway
Switch
Router
Bridge
Modem

network devices

Some of them are described below:-

1.Repeater:-

Repeaters have two ports and can connect two segments of a LAN. It amplifies the signals when they are transported over a long distance so that the signal can be as strong as the original signal. A repeater boosts the signal back to its correct level.

The main function of this device is to reproduce the

signal on a similar network before the signal gets weak otherwise damaged. The significant point to be noted regarding these devices is that they do not strengthen the signal. Whenever the signal gets weak, then they reproduce it at the actual strength. A repeater is a two-port device.

2.Hub:-

Hub is a like a repeater with multiple ports used to connect the network channels. It acts as a centralised connection to several computers with the central node or server. When a hub receives a packet of data at one of its ports from one network channel, it transmits the packet to all of its ports to all other channel.

The transferring of data in a computer network can be done in the form of packets.

The network hub is one kind of networking device in a computer network, used to communicate with various network hosts and also for data transferring.

3.Gateway:-

It is an interconnecting device, which joins two different network protocols together. They are also known as protocol converters. It accepts packet formatted for one protocol and converts the formatted packet into another protocol.

The gateway is a node in a network which serves as a proxy server and a firewall system and prevents the unauthorised access.

4.Switch:-

It is small hardware device that joins multiple computers together within one LAN. It helps to reduce overall network traffic.

Whenever a data packet is obtained from the interfaces in the switch, then the data packet can be filtered & transmits to

the interface of the receiver. Due to this reason, a switch maintains a content addressable memory table to maintain system configuration as well as memory.

Switch forwards a data packet to a specific route by establishing a temporary connection between the source and the destination. There is a vast difference between a switch and a hub. A hub forwards each incoming packet(data) to all the hub ports, while a switch forwards each incoming packet to the specified recipient.

5.Router:-

Router is a hardware device which is designed to take incoming packets, analyse packets, moving and converting packets to the another network interface, dropping the packets, directing packets to the appropriate locations, etc.

6.Bridge:-

It serves a similar function as switches. A bridge filters data traffic 🚥 at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments. Traditional bridges support one network boundary, whereas switches usually offer four or more hardware ports. Switches are sometimes called multiport bridges.

A Bridge in the computer network is used to group two or more network segments.

The main function of a bridge in network architecture is to store as well as transmit frames among the various segments. Bridges use MAC (Media Access Control) hardware for transferring frames.

7.Modem:-

It stands for Modulator-Demodulator(MODEM). It is a device that converts digital signal into analog signal(modulator) at the sender's end and convert back analog signal to digital signal 📶(demodulator) at the receiver's end, in order to make communication possible via telephone lines.

A modem is the most important network device that we used in our daily life.

A Modem is always placed between a telephone line and a computer.

What is Pen Drive and its uses:-

How to transfer files in Pen drive(USB Flash Drive):-

How To use a Pen Drive :-

Memory Cards:-

Some of the most popular forms of memory cards are:

What is Internet?

History of Internet:-

Advantages of Internet:-

Disadvantages of Internet:-

How Internet connects?

Wireless Connection:-

Other similar Topics related to this article:-

Introduction to World Wide Web(WWW):-

Definition of Interconnecting Protocols:-

Introduction to Domain Name:-

Definition of Blogs:-

Computer Architecture:-

Components of Computer:-

1.Input Unit:-

2.Output Unit:-

3.Central Processing Unit:-

Note:-

What is Motherboard:-

Components of Motherboard:-

1.Internal Bus:

Instruction Format:-

Some useful terms related to to computer architecture:-

What are Some solutions to Computer Security:-

Some popular antiviruses are follows:-

There are two common modes of a computer password are as follows:-

What are the Effect's of Virus:-

Types of Viruses:-

Symptoms of Malware Attack:-

Some Other Threats to Computer Security:-

Terms Related to Computer Security:-

Definition Of Computer Security :-

Methods to Provide Protection:-

Components of Computer Security:-

Sources of Cyber Attack:-

Lets understand what is Malware?

Virus:-

Types Of Virus:-

Network Topology:

The most commonly used topology are described below:-

Models Of Computer Networking:-

Notes:-

OSI Model:-

There are Seven Layers in OSI Model as follows:-

Some other terms related to Network:-

Network Devices:-

Types of Network Devices:-

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