foc_unit 2 notes.docx

**MS-DOS** MS-DOS, or Microsoft Disk Operating System, is a **command-line operating system** that was widely used before the advent of modern graphical interfaces. **What Are MS-Dos Commands?** MS-DOS is a character/text-based system of Microsoft Operating System, The users interact with the com...

**MS-DOS** MS-DOS, or Microsoft Disk Operating System, is a **command-line operating system** that was widely used before the advent of modern graphical interfaces. **What Are MS-Dos Commands?** MS-DOS is a character/text-based system of Microsoft Operating System, The users interact with the computer by typing text-based commands rather than a Graphical User Interface. These commands allow users to perform various tasks, **such as copying, deleting, or moving files, and managing programs.** **Why are MS-Dos Commands used?** - **File Management**: MS-Dos commands enable users to navigate through directories and create, delete, or copy files, enabling efficient file management. - **System Configuration: **Users can configure system settings, manage drives, and analyze hardware issues using MS Dos commands, providing a robust toolkit for system customization. - **Program Execution: **MS-Dos for commands facilitate the execution of programs and scripts, offering a streamlined approach to launching applications without the need for graphical interfaces. Types of DOS Commands - **Internal Commands** − Internal commands are the commands that are built into the command interpreter or the command prompt of the DOS operating system. These commands do not require a separate executable file to run and can be used directly from the command prompt. - **External Commands** − External commands in DOS are commands that are not built into the command interpreter, but are separate executable files that need to be located in the system\'s path or directory to be executed from the command prompt. External commands are usually more complex and are used for more advanced tasks than internal commands. - **List of MS-Dos Commands** Here's a table of some of the essential and commonly used commands MS-Dos for Commands for quick reference: **Command** **Syntax** **Description** ------------- --------------------------------------------------------------------------------------------------------- ------------------------------------------------------------- **CD** CD \[drive:\]\[path\]Change Changes the current directory to a specified directory **DIR** DIR \[drive:\]\[path\] Displays a list of files and subdirectories in a directory. **COPY** COPY \[destination\] Copies files from one location to another. **DEL** DEL \[drive:\]\[path\] Deletes one or more files. **REN** REN \[drive:\]\[path\]\[filename1\] \[filename2\] Renames a file or directory. **MKDIR** MKDIR \[drive:\]\[path\] Creates a new directory. **RMDIR** RMDIR \[drive:\]\[path\] Removes an existing directory. **TYPE** TYPE \[drive:\]\[path\] filename Displays the contents of a text file. **EDIT** EDIT \[drive:\]\[path\]filename Opens the MS-DOS text editor for editing a specified file. **CHKDSK** CHKDSK \[volume:\]\[\[path\]filename\] \[/F\] \[/V\] \[/R\] \[/X\] \[/I\] \[/C\] \[/L\[:size\]\] \[/B\] Scans and fixes errors on a disk. **FORMAT** FORMAT volume \[/FS:file-system\] \[/V:label\] \[/Q\] \[/L\[:size\]\] \[/A:size\] \[/C\] \[/X\] Prepares a storage medium for data storage. **XCOPY** XCOPY \[destination\] \[/E\] \[/C\] \[/H\] \[/R\] \[/Y\] Copies files and **DATE** DATE \[MM-DD-YYYY\] Displays or sets the system date. **TIME** TIME \[HH: MM: SS\] Displays or sets the system time. **HELP** HELP \[command\] Provides help information for MS-DOS commands. **EXIT** EXIT Exits the MS-DOS command prompt or a batch file. **What is Windows?** Windows Windows is a **graphical operating system** developed by Microsoft. It allows users to view and store files, run the software, play games, watch videos, and provides a way to connect to the internet. It was released for both home computing and professional works. **Microsoft introduced the first version as 1.0** It was released for both home computing and professional functions of Windows on **10 November 1983**. Later, it was released on many versions of Windows as well as the current version, Windows **10.** **Most Popular versions of windows:**  A black and white logo Description automatically generated Windows 3.0  Windows 7 Windows 95  Windows 98 Windows Vista  Windows XP Windows 10  Windows 2000 **Why is Microsoft Windows called Windows?** When Microsoft Windows was not introduced, all of the Microsoft users were used MS-DOS operating system. Microsoft gave one word to most of its products; it required a new Word that can represent its new [GUI](https://www.javatpoint.com/gui-full-form) operating system. Microsoft decided to call it Windows because it has the ability to perform several tasks and run applications simultaneously. Another reason behind calling it Windows was that you could not trademark a common name like Windows. Its official name was Microsoft Windows, the first version 1.0 of Windows was introduced in 1995. **What is the Internet?** Internet is a global network that connects billions of computers across the world with each other and to the World Wide Web. It uses standard internet protocol suite (**TCP/IP)** to connect billions of computer users worldwide. It is set up by using cables such as optical fibers and other wireless and networking technologies. At present, internet is the fastest mean of sending or exchanging information and data between computers across the world. Internet It is believed that the internet was developed by \"**Defense Advanced Projects Agency\" (DARPA)** department of the United States. And, it was first connected in **1969.** **Why is the Internet Called a Network?** Internet is called a network as it creates a network by connecting computers and servers across the world using routers, switches and telephone lines, and other communication devices and channels. So, it can be considered a global network of physical cables such as copper telephone wires, fiber optic cables, tv cables, etc. Furthermore, even wireless connections like 3G, 4G, or Wi-Fi make use of these cables to access the Internet. Internet is different from the [World Wide Web](https://www.javatpoint.com/what-is-world-wide-web) as the World Wide Web is a network of computers and servers created by connecting them through the internet. So, the internet is the backbone of the web as it provides the technical infrastructure to establish the [WWW](https://www.javatpoint.com/www-full-form) and acts as a medium to transmit information from one computer to another computer. It uses web browsers to display the information on the client, which it fetches from web servers. **The internet is not owned by a single person or organization entirely. It is a concept based on physical infrastructure that connects networks with other networks to create a global network of billions of computers. As of 12 August 2016, there were more than 300 crores of internet users across the world.** **How does internet work?** **Before understanding this let us understand some basics related to internet:** The internet works with the help of clients and servers. A device such as a laptop, which is connected to the internet is called a client, not a server as it is not directly connected to the internet. However, it is indirectly connected to the internet through an Internet Service Provider (ISP) and is identified by an IP address, which is a string of numbers. Just like you have an address for your home that uniquely identifies your home, an IP address acts as the shipping address of your device. The IP address is provided by your ISP, and you can see what [IP](https://www.javatpoint.com/ip-full-form) address your ISP has given to your system. **A server is a large computer that stores websites**. It also has an IP address. A place where a large number of servers are stored is called a data center. The server accepts requests send by the client through a browser over a network (internet) and responds accordingly. To access the internet we need a domain name, which represents an IP address number, i.e., each IP address has been assigned a domain name. For example, youtube.com, facebook.com, paypal.com are used to represent the IP addresses. Domain names are created as it is difficult for a person to remember a long string of numbers. However, internet does not understand the domain name, it understands the IP address, so when you enter the domain name in the browser search bar, the internet has to get the IP addresses of this domain name from a huge phone book, which is known as [DNS](https://www.javatpoint.com/dns-full-form) (Domain Name Server). For example, if you have a person\'s name, you can find his phone number in a phone book by searching his name. The internet uses the DNS server in the same way to find the IP address of the domain name. DNS servers are managed by ISPs or similar organizations. **Now after understanding the basics, let us see how internet works?**  When you turn on your computer and type a domain name in the browser search bar, your browser sends a request to the DNS server to get the corresponding IP address. After getting the IP address, the browser forwards the request to the respective server. Once the server gets the request to provide information about a particular website, the data starts flowing. The data is transferred through the optical fiber cables in digital format or in the form of light pulses. As the servers are placed at distant places, the data may have to travel thousands of miles through optical fiber cable to reach your computer. The optical fiber is connected to a router, which converts the light signals into electrical signals. These electrical signals are transmitted to your laptop using an Ethernet cable. Thus, you receive the desired information through the internet, which is actually a cable that connects you with the server. Furthermore, if you are using wireless internet using wifi or mobile data, the signals from the optical cable are first sent to a cell tower and from where it reaches to your cell phone in the form of electromagnetic waves. The internet is managed by ICANN (Internet Corporation for Assigned Names and Numbers) located in the USA. It manages IP addresses assignment, [domain](https://www.javatpoint.com/what-is-domain) name registration, etc. The data transfer is very fast on the internet. The moment you press enter you get the information from a server located thousands of miles away from you. The reason for this speed is that the data is sent in the binary form (0, 1), and these zeros and ones are divided into small pieces called packets, which can be sent at high speed. **Uses of the internet** Generally speaking, the Internet may be used to exchange information with people all over the world, communicate across great distances, and locate information or answers fast on almost any subject. Here are some examples of specific uses for the Internet: - Using social media and content sharing. - Instant messaging, video conferencing, Internet Relay Chat (IRC), Internet telephony, and email are all examples of electronic communication. These all are used through the Internet. - Access to online degree programs, courses, and workshops for education and self-improvement. - Searching for jobs: To advertise available positions, submit job applications, and hire candidates identified on social networking sites like LinkedIn, both employers and applicants use the Internet. Other examples include: - Online dating - Online gaming - Research - Reading electronic newspapers and magazines - Online shopping, or e-commerce. - Online discussion groups and forums **History of the Internet** The forerunner of the Internet, the ARPANet, went live for the first time in **1969**. The TCP/IP, open networking protocol suite, was adopted by the ARPANet in 1983, and the National Science Foundation Network (NSFN) developed the network to link university computer science departments across the US in 1985. When the hypertext transfer protocol (HTTP) was developed in 1989, it enabled different computer platforms to connect to the same Internet sites, which dramatically improved communications over the network. The Mosaic Web browser was developed in **1993**. Over the years of its existence, the Internet has remained a constant growth and development. For instance, IPv6 was created to provide for a significant future rise in the number of IP addresses that could be used. In a related development, the Internet of Things (IoT) refers to the rapidly developing environment where nearly any entity or device can be given a unique identifier (UID) and the capability to communicate data automatically over the Internet. **Advantages of the Internet:** - **Instant Messaging:** You can send messages or communicate to anyone using internet, such as email, voice chat, video conferencing, etc. - **Get directions:** Using GPS technology, you can get directions to almost every place in a city, country, etc. You can find restaurants, malls, or any other service near your location. - **Online Shopping:** It allows you to shop online such as you can be clothes, shoes, book movie tickets, railway tickets, flight tickets, and more. - **Pay Bills:** You can pay your bills online, such as electricity bills, gas bills, college fees, etc. - **Online Banking:** It allows you to use internet banking in which you can check your balance, receive or transfer money, get a statement, request cheque-book, etc. - **Online Selling:** You can sell your products or services online. It helps you reach more customers and thus increases your sales and profit. - **Work from Home:** In case you need to work from home, you can do it using a system with internet access. Today, many companies allow their employees to work from home. - **Entertainment:** You can listen to online music, watch videos or movies, play online games. - **Cloud computing:** It enables you to connect your computers and internet-enabled devices to cloud services such as cloud storage, cloud computing, etc. - **Career building:** You can search for jobs online on different job portals and send you CV through email if required. **Disadvantages of the Internet** - **Time wastage:** Although, Internet has a lot of advantages, it also contains some limitations. Time wasting is one of among them. It can decrease your productivity if you are spending too much time on the Internet using social media apps while doing nothing. Rather than squandering time, one should use that time to do something useful and even more productive. - **Bad impacts on health:** You can get health related issues if you spend too much time online; your body needs outside activities, exercise, and many other things. If you look at the screen for a long time, it causes negative effects on the eyes. - **Cyber Crimes:** These days, crimes including cyberbullying, spam, viruses, hacking, and data theft are increasing day by day. Cybercriminals can quickly break into your system, which store all of your private information. - **Effects on children:** The constant watching of videos and playing games on the Internet by young children is bad for their social and overall personality development. - **Bullying and spreading negativity:** Social media applications have provided a free tool to all those people who regularly attempt to spread negativity with really repulsive and humiliating comments and try to bully each other, which is wrong and does bad impact on society. **TCP/IP model** - The TCP/IP model is a communication model.. - The TCP/IP model consists of five layers: the application layer, transport layer, network layer, data link layer and physical layer. - TCP/IP is a hierarchical protocol made up of interactive modules, and each of them provides specific functionality. Here, hierarchical means that each upper-layer protocol is supported by two or more lower-level protocols. **Protocols works at TCP/IP layers:** TCP/IP model Functions of each layer in TCP/IP model