History of Computers.pdf

History of Computers Early Devices: ○ Abacus (4000 years ago, China): First known computing tool, a wooden rack with metal rods and beads. Used for arithmetic by moving beads according to rules. ○ Napier’s Bones (Invented by John Napier): Manually operated...

History of Computers Early Devices: ○ Abacus (4000 years ago, China): First known computing tool, a wooden rack with metal rods and beads. Used for arithmetic by moving beads according to rules. ○ Napier’s Bones (Invented by John Napier): Manually operated with 9 ivory strips (bones). Used for multiplication and division, first to use decimal points. ○ Pascaline (1642-1644, Blaise Pascal): First mechanical and automatic calculator, helping Pascal’s father with tax calculations. It could perform addition and subtraction. ○ Stepped Reckoner (1673, Gottfried Leibniz): An improvement of Pascal’s design, it was a digital mechanical calculator using fluted drums. Advancements: ○ Difference Engine (1820s, Charles Babbage): Early mechanical computer powered by steam, capable of simple calculations like logarithms. ○ Analytical Engine (1830, Charles Babbage): First mechanical computer that used punch cards as input, capable of solving any mathematical problem with memory storage. ○ Tabulating Machine (1890, Herman Hollerith): Used punch cards for tabulating statistics, sorting data. It was used for the U.S. Census and led to the creation of IBM. ○ Differential Analyzer (1930, Vannevar Bush): First electronic computer, an analog device with vacuum tubes, performing up to 25 calculations per minute. ○ Mark I (1937-1944, Howard Aiken): First programmable digital computer, developed through IBM and Harvard collaboration. Generations of Computers First Generation (1940-1956): ○ Vacuum tubes used as CPU and memory components. ○ Batch operating systems and punch cards were common. ○ Machines were slow, huge, and expensive. ○ Examples: ENIAC, UNIVAC-1, EDVAC. Second Generation (1957-1963): ○ Transistors replaced vacuum tubes, making computers smaller, faster, and more energy-efficient. ○ Magnetic cores and tapes used for memory. ○ COBOL and FORTRAN languages were introduced. ○ Batch processing and multiprogramming began. Third Generation (1964-1970): ○ Integrated Circuits (ICs) replaced transistors, increasing computing power and reducing costs. ○ Remote processing, time-sharing, and high-level languages like FORTRAN-II to IV, COBOL, PASCAL became common. Fourth Generation (1971-1980): ○ Very Large Scale Integration (VLSI) circuits introduced, making computers more compact and affordable. ○ Real-time, time-sharing, and distributed OS used. ○ Programming languages: C, C++. Fifth Generation (1980–Present):  ○ Ultra Large Scale Integration (ULSI) technology introduced. ○ Microprocessors contain ten million+ components. ○ Parallel processing and AI software became prominent. ○ Languages: C, C++, Java,.Net. ○ Devices: Desktop, Laptop, Notebook, Ultrabook. Basics of Computer and its Operations Introduction to Computers: Computer: An electronic device that operates under the control of programs stored in its memory. ○ Processes raw data into meaningful information as output. ○ Executes instructions (programs) to perform tasks. ○ Full form: Commonly Operated Machine Particularly Used for Training, Education, and Research. Components of a Computer: Hardware: ○ Central Processing Unit (CPU) ○ Memory (RAM/Storage devices) ○ Input/Output devices (keyboard, mouse, etc.) ○ Peripherals (printers, scanners) Software: ○ Operating system (OS) ○ Applications (software programs) History of Computers: Early developments: Analytical Engine and tabulating machines in the 19th century. Modern computers emerged in the mid-20th century with transistors and integrated circuits. Importance and Uses: Widely used in industries like education, finance, healthcare, and entertainment. Enabled advancements such as the internet, cloud computing, and mobile devices. Functions of a Computer: Accepts data Stores data Processes data based on instructions Retrieves stored data Outputs results in the desired format Data and Information  Data: Raw facts and figures entered into a computer, unorganized and without inherent meaning. ○ Examples: numbers, words, images, sounds. ○ Data by itself is not useful until processed. Information: Data that has been processed, organized, and given context to become meaningful and useful. ○ Example: Sales figures processed into a graph showing trends over time, which can aid in decision-making. Key Difference: Data is unprocessed and unorganized, while information is data that has been refined for practical use. Classification of Computers Based on Design and Technology: 1. Digital Computers: ○ Process information in discrete (binary) form (0s and 1s). ○ Common in industrial, business, and scientific applications. ○ Suitable for large-volume data processing. 2. Analog Computers: ○ Process continuous data, often from physical processes. ○ Example: Thermometers, simulations in aircrafts and nuclear power plants. ○ Suitable for real-time simulation tasks. 3. Hybrid Computers: ○ Combine analog and digital technology. ○ Provide the speed of analog and accuracy of digital. ○ Common in complex simulations. Based on Functionality and Size: 4. Supercomputers: ○ Most powerful, used for complex scientific calculations. ○ Examples: Weather forecasting, cryptography, nuclear research. 5. Mainframe Computers: ○ Large, powerful systems for organizations. ○ Used in banking, airlines, and government sectors for large-scale data processing. 6. Mini Computers: ○ Smaller than mainframes, used by small to medium businesses. ○ Handle tasks like accounting and inventory management. 7. Personal Computers: ○ Affordable, designed for individual use. ○ Used for personal productivity, entertainment, and communication. 8. Workstations: ○ High-performance computers for professionals (architects, engineers). ○ Used for 3D modeling, animation, scientific visualization. 9. Embedded Systems: ○ Specialized computers within other devices (e.g., cars, appliances). ○ Perform specific control functions.  10. Mobile Devices: ○ Portable, designed for on-the-go use. ○ Examples: Smartphones, tablets, laptops. Classification of Digital Computers 1. Microcomputers: ○ Also known as Personal Computers (PCs). ○ Use a microprocessor (CPU on a single chip). ○ Include desktops, laptops, PDAs, and tablets. ○ Handle small volumes of data; versatile for tasks like CAD, multimedia, and workstations. 2. Minicomputers: ○ Support multiple users simultaneously. ○ Used in organizations where departments are interconnected. ○ Suitable for small businesses. 3. Mainframe Computers: ○ Large, powerful with high memory capacity. ○ Process huge databases (e.g., census) at high speed. ○ Used by big organizations, banks, and industries; support hundreds of users on a network. 4. Supercomputers: ○ Fastest and most expensive. ○ Perform billions of instructions per second. ○ Multiprocessor systems used for complex scientific applications like weather forecasting. 5. Workstations: ○ High-performance computers for professionals. ○ Used for tasks like 3D modeling, animation, and scientific visualization. 6. Embedded Systems: ○ Specialized computers embedded in devices (cars, appliances, medical equipment). ○ Perform specific control functions. 7. Mobile Devices: ○ Portable computers designed for mobility. ○ Examples: smartphones, tablets, laptops. Peripheral Devices Peripheral devices are external components connected to a computer, enabling it to perform specific functions by inputting and outputting data based on user requirements. Types of Peripheral Devices: Input Devices: ○ Keyboard: For text input and commands. ○ Mouse: Pointing device for navigation. ○ Light Pen: Used for drawing and selecting on a screen. ○ Optical/Magnetic Scanner: Digitizes physical documents. ○ Touch Screen: Allows direct interaction with the display. ○ Microphone: Captures voice as input. ○ Track Ball: An alternative pointing device with a movable ball. Output Devices: ○ Monitor (Visual Display Unit): Displays visual output.  ○ Printers: Produces hard copies of digital documents. ○ Plotter: Creates high-quality graphical prints. ○ Speaker: Outputs audio. Difference Between RAM and Hard Disk RAM Hard Disk Type: Electronic device Type: Electromechanical device Speed: Faster than hard disk Speed: Slower than RAM Connection: Directly connected to CPU via Connection: No direct connection to CPU buses Function: Volatile memory; allows fast data Function: Non-volatile storage; used for processing and multitasking long-term data storage Data Loss: Contents lost when power is off Data Preservation: Contents preserved when power is off Usage: Temporary storage for active data and Usage: Long-term storage for files and programs applications Types of Software 1. System Software: ○ Essential for the operation of a computer or device. ○ Enables hardware and application software to interact. ○ Examples: Linux, Unix, Windows. 2. Application Software: ○ Not necessary for the basic operation of a device; enhances functionality. ○ Used for specific tasks or activities. ○ Examples: Facebook, WhatsApp, games. Difference Between Hacker and Cracker 1. Hacker:  ○ Warns users about potential malicious activities. ○ Does not steal information; often aims to improve security. 2. Cracker: ○ Intentionally steals information without user knowledge. ○ Engages in malicious activities for personal gain. Basic Computer Operations 1. Booting Up: ○ The process of starting the computer and loading the operating system (OS) into memory. ○ Includes running checks to ensure all hardware is functioning properly. 2. Logging In: ○ Entering your username and password to access your user account after booting up. 3. Running Programs: ○ Once logged in, you can launch various programs such as web browsers, office applications, and media players. 4. Accessing Data: ○ Retrieve data stored on your computer or connected devices (e.g., external hard drives, cloud storage). ○ Includes files, documents, photos, and media. 5. Connecting to the Internet: ○ Use a web browser to access websites, download files, and communicate online. 6. Communicating with Other Devices: ○ Interact with connected devices like printers and scanners to print documents or scan images. 7. Saving and Backing Up Data: ○ Regularly save and back up data to avoid loss. ○ Save to local hard drives, external drives, or cloud storage. 8. Shutting Down: ○ Properly close all programs and files before shutting down the OS to ensure data is saved. 9. Troubleshooting: ○ Diagnose and resolve issues related to hardware or software, perform updates, or reinstall drivers as needed. 10. Security: ○ Keep your computer secure with antivirus software, firewalls, and other measures to protect data and prevent unauthorized access. Issues with Basic Computers and Computer Operations 1. Slow Performance: ○ Computers can become sluggish and unresponsive due to insufficient storage space, outdated hardware, or malware. 2. Malware and Viruses: ○ Malicious software can infect computers, causing problems such as data loss, system crashes, and identity theft. 3. Hardware Failures: ○ Hardware components can fail over time, resulting in system crashes, data loss, and display issues. 4. Software Glitches: ○ Software applications may malfunction or crash, leading to data loss or unresponsive programs.  5. Driver Problems: ○ Outdated or corrupted drivers can hinder hardware communication with the operating system, causing hardware failures or system crashes. 6. Compatibility Issues: ○ Incompatibilities between software applications or hardware components can lead to system crashes or display problems. 7. Internet Connectivity Issues: ○ Problems with internet connections can result in slow-loading web pages, interrupted downloads, and difficulty accessing online services. 8. User Error: ○ Mistakes made by users, such as accidentally deleting files or programs, can lead to data loss or unresponsive applications. Characteristics of Computers Speed: Computers perform calculations and tasks in seconds that would take hours for humans. Their speed is measured in Gigahertz (GHz) and Megahertz (MHz). Accuracy: Computers offer high accuracy, with errors typically arising from incorrect data input by users. They can execute tasks quickly and with precision. Memory: Computers can store vast amounts of data, accessible with high accuracy. Storage is measured in Bytes, such as Kilobytes (KB), Megabytes (MB), and Gigabytes (GB). Versatility: Computers can perform multiple tasks simultaneously, making them highly versatile. Automation: With advancements in Artificial Intelligence (AI), computers can automate tasks that previously required human labor. Advantages of Computers Multitasking: Computers can handle multiple tasks and calculations simultaneously, performing millions or trillions of operations in one second. Speed: Computers significantly reduce the time required to complete tasks. Cost Efficiency: Centralized databases allow for storing vast amounts of information at a lower cost. Accuracy: Computers perform calculations with a high degree of accuracy. Data Security: Computers help in protecting digital data through various security measures. Task Completion: They can perform tasks that may be impossible for humans. Communication: Computers enhance understanding and communication with other devices. Productivity: They can double productivity by performing tasks quickly. Reduced Workload: Information can be accessed by multiple users, minimizing duplication of work. Reliability: Computers consistently perform tasks without errors due to tiredness or boredom. Storage: They offer significant in-built memory and can store large amounts of data on auxiliary storage devices. Disadvantages of Computers Virus and Hacking Attacks: Viruses can spread through email attachments and infected websites, leading to unauthorized access. Online Cyber Crimes: Computers can be used for illegal activities, including cyberstalking and fraud. Reduction in Employment Opportunities: The rise of computers can lead to job loss, especially for those lacking computer skills. High Cost: Computers can be expensive, making them less accessible for some individuals.  Distractions/Disruptions: The entertainment value of computers can lead to time-wasting activities, such as excessive browsing. Environmental Impact: Rapid replacement of electronic devices contributes to waste and environmental issues. Health Problems: Prolonged use can cause eye strain, neck and back issues, and other health hazards. Computer System A computer system is a collection of entities (hardware, software, and liveware) designed to receive, process, manage, and present information in a meaningful form. Components Of Computer System A computer system consists of two major components: 1. Hardware: The physical devices of the computer that we can see and touch. ○ Examples: Monitor, Central Processing Unit (CPU), Mouse, Joystick, etc. 2. Software: The programs and operating systems that run on the hardware. Computer Hardware Parts Hardware components are further divided into the following categories: 1. Input Devices 2. Output Devices 3. Storage Devices 4. Internal Components 1. Input Devices Input devices allow users to interact with the computer and enter data. Some examples include: Keyboard: The main input device with 104 keys used for typing data. It can be connected via cable or Bluetooth. Mouse: A pointing device used to control the cursor. It has functional buttons for selecting and opening files. Scanner: Converts images and documents into digital form for editing and use. Track Ball: A stationary device where the user rolls a ball to move the cursor on the screen. Light Pen: A light-sensitive device used to draw on the screen. Microphone: Captures sound and converts it into electrical signals for processing. Optical Character Reader (OCR): Detects alphanumeric characters on paper using light. Bar Code Reader: Reads bar codes and converts them into electronic signals. 2. Output Devices Output devices display or present the results of the computer's processes. Some examples include: Monitor: The primary output device, similar to a TV screen, displaying text, images, and videos. Printer: Produces hard copies of documents and images. Types include laser, dot-matrix, and inkjet printers. Plotter: Similar to a printer but larger, used for generating high-quality drawings and blueprints. Speakers: Output sound and are used for music and other audio. 3. Storage Devices Storage devices are used for storing data and are known as secondary storage devices. Some examples include: 1. CD (Compact Disc): A circular disc with a storage capacity of 600 MB to 700 MB. Types include: ○ CD-ROM: Read-only memory; data cannot be erased or rewritten. ○ CD-R: Recordable; data can be written once and read multiple times. ○ CD-RW: Rewritable; data can be erased and rewritten multiple times. 2. DVD (Digital Video/Versatile Disc): Offers greater storage capacity than CDs. Capacity includes: ○ Single-layer (4.7 GB) and double-layer (8.5 GB) options. 3. Types include: ○ DVD-ROM: Read-only; data cannot be erased or written over. ○ DVD-R/DVD+R: Recordable discs. ○ DVD-RW/DVD+RW: Rewritable discs. ○ DVD-RAM: High-capacity rewritable disc with multiple uses. 4. Hard Disk: A non-volatile storage device that uses magnetic surfaces to store digital data. Standard sizes are 3.5 inches for desktops and 2.5 inches for laptops. Hardware Components 1. CPU (Central Processing Unit) ○ Known as the "heart" of the computer, the CPU consists of three main units: Control Unit: Directs operations and manages instructions from memory. Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations (addition, subtraction, multiplication, division, etc.). Memory Unit: Stores data and instructions temporarily. ○ Functionality: Input is received through input devices, processed according to instructions, and results are stored in memory before being sent to output devices. 2. Motherboard ○ The main circuit board of a computer, connecting all components. ○ Includes RAM slots, controllers, and system chipsets. ○ Serves as the backbone for communication between hardware components. 3. RAM (Random Access Memory) ○ Temporary or volatile memory that holds data and programs currently in use. ○ Data is lost when the computer is powered off. ○ Types of RAM: SRAM (Static RAM): Fast, uses flip-flops, doesn't require refreshing, but is expensive and requires more space (used for cache memory).  DRAM (Dynamic RAM): Slower, uses capacitors, requires periodic refreshing due to leakage (used for main memory). 4. Video Graphics Array (VGA) Port ○ A standard video input connection used for computer monitors to display graphics. 5. Power Supply ○ Converts AC voltage from an electrical outlet to DC voltages that power all computer components. ○ Ensures stable power delivery to the system. 6. Cooling Fan ○ Prevents overheating by circulating air within the computer case. ○ Essential for high-performance tasks like gaming or video streaming; often multiple fans are used. 7. Hard Drive ○ A data storage device that uses magnetically coated discs to store files, programs, and other types of information. ○ Non-volatile storage that retains data even when the computer is turned off. Software and Its Types Software is a collection of instructions, data, or computer programs that instruct a computer on how to perform specific tasks. Types of Software 1. System Software 2. Application Software System Software Directly operates computer hardware, providing basic functionality for users and other software. Controls a computer’s internal operations and manages hardware devices (e.g., monitors, printers, storage). Types of System Software 1. Operating System ○ The primary software that loads when a computer starts. It manages resources like memory, CPU, and storage. ○ Examples: Linux, Apple macOS, Microsoft Windows. 2. Language Processor ○ Converts human-readable programming languages into machine-readable code. It allows programmers to write code in high-level languages. ○ Function: Translates source code (e.g., Java, C, Python) into object code (machine code). 3. Device Driver ○ Software that controls a specific hardware device, enabling it to communicate with the computer. ○ Function: Required for devices like printers and modems to function correctly with the operating system. Installation of the driver is necessary for the device to operate. Application Software Software designed to help users perform specific tasks or activities. Unlike system software, it is not essential for the basic operation of the computer. Types of Application Software 1. General Purpose Software ○ Software that can perform a variety of tasks (e.g., word processing, spreadsheets). ○ Examples: Microsoft Office, Google Docs. 2. Customized Software ○ Software specifically designed and developed for a particular user or organization to meet specific needs. ○ Examples: Tailored business applications, specialized databases. 3. Utility Software ○ Software designed to help manage, maintain, and control computer resources. ○ Examples: Antivirus programs, file management tools, backup software. Number Systems and Data Representation Data Representation Representation = Measurement: In the real world, things are measured as continuously varying quantities (e.g., mass, volume, speed). Analog Measurements: These are direct representations of continuous values, such as pressure measured by the height of a mercury column. Digital Representation Digital Measurements: These involve discrete values (symbols or digits), allowing representation of values through sequences (e.g., units, tens, hundreds). Binary System: Computers use a binary system (base-2), representing all data as binary digits (bits), which are either 0 or 1. Number Systems 1. Decimal System (Base-10): ○ Uses 10 distinct digits (0-9). ○ Each digit's value depends on its position, based on powers of 10. ○ Example: 2. Binary System (Base-2):  Uses 2 distinct digits (0 and 1). Each digit's value depends on its position, based on powers of 2. Example: Conversions Decimal to Binary Conversion: To convert a decimal number to binary: ○ Step 1: Divide the number by 2 and note the quotient and remainder. ○ Step 2: Record the remainder (0 or 1). ○ Step 3: Continue dividing the quotient by 2 until it becomes 0. ○ Step 4: Write the remainders in reverse order. Binary to Decimal Conversion: To convert binary to decimal: ○ Write the binary number and assign powers of 2 from right to left. ○ Multiply each digit by its corresponding power of 2 and sum the results. Octal to Binary Conversion: Each octal digit can be replaced by its corresponding 3-bit binary representation. Hexadecimal to Octal Conversion: Convert hexadecimal to decimal first, then from decimal to octal. The Internet Why is the Internet Called a Network? The Internet connects computers and servers worldwide through routers, switches, and communication devices. It comprises a global network of physical cables (copper wires, fiber optics, TV cables) and wireless connections (3G, 4G, Wi-Fi) for access. What is the Internet? Developed by the Defense Advanced Research Projects Agency (DARPA) in 1969. Utilizes TCP/IP (Transmission Control Protocol/Internet Protocol), a suite of communication protocols for network devices. ○ Intranet: A secure, private network for internal communication within an organization. ○ Extranet: A private network providing controlled access to external third parties. Overview  The Internet is a global network connecting billions of computers and users via the World Wide Web (WWW). It operates on the TCP/IP protocol suite, utilizing optical fibers and wireless technologies. Currently, it is the fastest means of exchanging information and data. Distinction Between Internet and WWW The Internet is the backbone for the WWW, providing the technical infrastructure for connecting computers and transmitting information. Web browsers display information fetched from web servers over the Internet. Ownership The Internet is not owned by any single person or organization; it is a concept based on the physical infrastructure connecting networks to form a global network of billions of computers. Internet Set Up Transmission Cables: Uses physical copper or optical fiber cables, and networking technologies like LAN, WAN, and MAN. ○ LAN (Local Area Network): Connects devices in one physical location (e.g., home, office). ○ WAN (Wide Area Network): Connects multiple LANs, linking offices, data centers, and cloud systems. ○ MAN (Metropolitan Area Network): Connects multiple LANs across a large area but is smaller than WAN. How the Internet Works Clients & Servers: ○ A device connected to the internet (e.g., laptop) is a client, identified by an IP address assigned by an Internet Service Provider (ISP). ○ Servers: Store websites and respond to client requests. Large groups of servers are stored in data centers. Domain Names & IP Addresses: ○ Each IP address is represented by a domain name (e.g., youtube.com), managed by DNS (Domain Name Server) to convert domain names into IP addresses. Internet Process: ○ The client enters a domain name in the browser, which sends a request to the DNS server. ○ DNS retrieves the corresponding IP address, and the request is forwarded to the server. ○ Data travels via optical fiber cables in digital format (light pulses), often covering thousands of miles. Signal Transmission: ○ Routers convert light signals from optical fiber into electrical signals sent to devices via Ethernet cables. ○ For wireless internet (WiFi or mobile data), signals are sent to cell towers and then reach devices as electromagnetic waves. Internet Management: Overseen by ICANN (Internet Corporation for Assigned Names and Numbers), responsible for IP addresses and domain name registrations. Data Transfer:  ○ Data is transferred rapidly in binary form (0s and 1s), divided into packets for high-speed transmission. Uses of the Internet General Uses: ○ Exchange information globally. ○ Communicate across long distances. ○ Quickly locate information on almost any topic. Specific Uses of the Internet Social Media & Content Sharing: Platforms for connecting and sharing. Electronic Communication: Examples include instant messaging, video conferencing, Internet Relay Chat (IRC), Internet telephony, and email. Education: Access to online degree programs, courses, and workshops. Job Searching: Employers and applicants use platforms like LinkedIn to advertise jobs, submit applications, and recruit candidates. Other Examples Online Dating Online Gaming Research Reading: Electronic newspapers and magazines. E-commerce: Online shopping. Online Forums & Discussion Groups Difference Between the World Wide Web and the Internet Internet: ○ A global network of interconnected networks. ○ Provides access to a wide variety of information and services. World Wide Web (Web): ○ A collection of information that can be accessed using the Internet. ○ A service built on top of the Internet. ○ Primarily handles the highest traffic on the Internet. Key Features of the Web Hypertext: ○ Uses highlighted keywords, phrases, buttons, and graphics as hyperlinks to rapidly cross-reference and navigate to other websites or pages. Web Browsers: ○ Programs used to browse the Web (e.g., Google Chrome, Firefox, Internet Explorer). ○ Different browsers may display the same website slightly differently. ○ Newer browser versions support advanced features like sound, animation, and virtual reality. Security and the Internet  Risks: ○ High volume of online information makes customers vulnerable to security attacks and data breaches. ○ Crackers (outdated term) and Hackers can break into systems, steal personal data (passwords, bank info), or install malware. Steps to Protect Online Privacy Install antivirus and antimalware software. Use complex, unique passwords. Use a Virtual Private Network (VPN) or private browsing modes (e.g., Incognito in Chrome). Ensure websites use HTTPS (Hypertext Transfer Protocol Secure) for secure data transfer. Keep social media accounts private. Deactivate autofill features. Turn off GPS on devices. Log out of accounts instead of just closing the tab/window. Set cookie alerts for notification of changes. Avoid spam emails and do not open unknown attachments. Be cautious when using public Wi-Fi or hotspots. Social Impact of the Internet Negative Effects: ○ Increased risk of withdrawal, social exclusion, alienation, and FOMO (Fear of Missing Out). Positive Effects: ○ Enhanced sociability, civic participation, and deeper connections. Communication Changes: ○ The Internet has shifted how society interacts, with less reliance on communities tied to space, job, or family. ○ Social connections are now often built on personal projects, values, and interests. ○ Platforms like Facebook and LinkedIn are widely used for both personal and business connections. Internet Connection Protocols Protocols are guidelines that regulate how technologies and networks operate. Types of Protocols: 1. TCP/IP Network Model: Transmission Control Protocol (TCP) and Internet Protocol (IP) break communication into packets sent between source and destination. 2. File Transfer Protocol (FTP): Used for transferring files (documents, multimedia, etc.) between devices. 3. Hypertext Transfer Protocol (HTTP): Moves hypertext between devices using HTML tags for text or graphics links. History of the Internet  1969: ARPANet (Advanced Research Projects Agency Network), the forerunner of the Internet, went live. 1983: ARPANet adopted the TCP/IP networking protocol, establishing the foundation for open networking. 1985: National Science Foundation Network (NSFN) developed to connect university computer science departments across the U.S. 1989: Development of the Hypertext Transfer Protocol (HTTP) allowed different computer platforms to connect to the same Internet sites, revolutionizing network communication. 1993: The Mosaic Web browser was developed, making the Web more accessible. Continual Growth: IPv6 was created to accommodate a large future increase in the number of IP addresses. Internet of Things (IoT) emerged, enabling devices and objects to have unique identifiers (UIDs) and communicate data automatically over the Internet. Advantages of the Internet Instant Messaging: Communicate via email, voice chat, video conferencing, etc. Get Directions: Use GPS technology to find directions and locate services (restaurants, malls) nearby. Online Shopping: Purchase items like clothes, shoes, movie tickets, and travel tickets. Pay Bills: Easily pay bills online (electricity, gas, college fees). Online Banking: Access banking services, check balances, transfer money, request statements, and order checkbooks. Online Selling: Sell products or services online, reaching more customers and increasing sales. Work from Home: Use internet access to work remotely; many companies support telecommuting. Entertainment: Stream music, watch videos or movies, and play online games. Cloud Computing: Connect to cloud services for storage and computing via internet-enabled devices. Career Building: Search for jobs on portals and send CVs via email. Disadvantages of the Internet Time Wastage: Excessive time on the Internet, particularly on social media, can decrease productivity. Time spent online should be directed toward more useful activities. Bad Impacts on Health: Prolonged online activity can lead to health issues, including a lack of physical exercise and negative effects on eye health from extended screen time. Cyber Crimes: Increasing incidents of cyberbullying, spam, viruses, hacking, and data theft pose significant risks. Cybercriminals can easily access personal information stored online. Effects on Children: Excessive screen time from watching videos and playing games can hinder young children's social skills and overall personality development. Bullying and Spreading Negativity: Social media platforms can facilitate negative behavior, including bullying and harmful comments, which have a detrimental effect on society. Different Ways to Connect to the Internet Dial-Up: ○ Connects via phone line to access the Internet. ○ Cannot make or receive calls while connected. Broadband: ○ The most popular high-speed connection.  ○ Offered by cable or phone companies. Wireless Connection: ○ Includes mobile and Wi-Fi services, allowing Internet access via radio waves. ○ Examples: Wi-Fi: Provides high-speed connectivity without cables. Mobile Phones: Smartphones enable Internet access through data packs without wires. Satellite: ○ Used for wireless Internet in areas without broadband. Integrated Services Digital Network (ISDN): ○ Allows audio and video data transmission using telephone lines. Other Things You Can Do on the Internet Instant Communication: ○ Communicate globally through email, a widely used method for sharing information. ○ Use social media platforms to connect and create online communities. Stay Informed: ○ Access news updates from various sources. Online Shopping: ○ Shop for goods and services from anywhere. Manage Finances: ○ Handle banking and financial affairs online. Socialize: ○ Meet new people and build relationships. Entertainment: ○ Watch TV shows and movies online. Skill Enhancement: ○ Learn new skills or take online courses. Data Representation Data: Symbols representing people, events, things, or ideas. Data Representation: Form in which data is stored, processed, and transmitted. Digitization: Converting information into digital data for manipulation by devices. Digital Revolution: Evolved from large, expensive computers to ubiquitous digital devices. Bits: The basic unit of digital data, represented as 0s and 1s. Digital File: A named collection of data on a storage medium (e.g., hard disk, CD, flash drive). Representing Numbers Numeric data consists of numbers usable in arithmetic operations. Binary System (Base 2): Digital devices use this system where numbers are represented using 0 and 1. Example: Decimal number 2 is represented as "10" in binary. Representing Text Character Data: ○ Composed of letters, symbols, and numerals not used in calculations (e.g., name, address, hair color). ○ Commonly referred to as "text." Encoding Schemes: ○ ASCII (American Standard Code for Information Interchange): Uses 7 bits for each character. Example: Uppercase "A" is represented as 1000001. ○ Extended ASCII: A superset of ASCII using 8 bits per character. Provides codes for 256 characters (e.g., "A" is 01000001). ○ Unicode: Uses 16 bits and supports 65,000 characters, accommodating multiple languages. UTF-8: A variable-length encoding that uses 7 bits for ASCII characters and 16 bits for others as needed. Text File Formats: ○ ASCII Text Files: Unformatted and typically have a.txt extension. Apple devices label them as "Plain Text," while Windows calls them "Text Document." ○ Formatted Text: Requires embedded formatting codes for styles. Common formats: DOCX: Produced by Microsoft Word. PAGES: Produced by Apple Pages. PDF: Produced by Adobe Acrobat. HTML: Used for web pages via markup language. Bits and Bytes Data Encoding: ○ All data in digital devices is encoded as bits (binary digits). ○ The abbreviation for bit is lowercase b; a group of eight bits is called a byte (uppercase B). Terminology: ○ Terms like kilo, mega, giga, and tera quantify digital data and are commonly used to describe storage capacity and network speeds. Usage: ○ Bits: Used for data rates (e.g., Internet speeds, download speeds). ○ Bytes: Used for file sizes and storage capacities. Common Measurements: Kilobyte (KB or Kbyte): ○ 1,024 bytes; often used for small files (e.g., 104 KB). Kilobit (Kb or Kbit): ○ 1,024 bits; used for slow data rates (e.g., 56 Kbps for dial-up connections). Megabit (Mb or Mbit): ○ 1,048,576 bits; used for faster rates (e.g., 50 Mbps for Internet connections).  Megabyte (MB or MByte): ○ 1,048,576 bytes; typically used for files like photos and videos (e.g., 3.2 MB). Gigabit (Gb or Gbit): ○ 1,073,741,824 bits; used for very fast network speeds (e.g., 100 Gbit). Gigabyte (GB or GByte): ○ 1,073,741,824 bytes; commonly refers to storage capacity (e.g., 16 GB). Data Compression Reduces file size and transmission times by recoding data to contain fewer bits. Commonly referred to as zipping. Types of Compression Lossless Compression: ○ Compresses data without losing any information. ○ The data can be reconstituted exactly as the original. Lossy Compression: ○ Discards some original data during compression. ○ The uncompressed data is not identical to the original. Compression Utilities Software for compressing data is called a compression utility or zip tool. These tools are often integrated into the file management system on laptops and desktops. Extracting Extracting or unzipping is the process of reconstituting compressed files. Common compressed file extensions include.zip,.gz,.pkg, and.tar.gz.