CSE 101-Principles of Computing Lecture Notes PDF

CSE 101-Principles of Computing Mekelle Institute of Technology Department of CSE 12/19/2024 1  CHAPTER -ONE Content Computers, parts of computers and their roles Data and Networking Operating systems Accounts Command prompt Command opti...

CSE 101-Principles of Computing Mekelle Institute of Technology Department of CSE 12/19/2024 1  CHAPTER -ONE Content Computers, parts of computers and their roles Data and Networking Operating systems Accounts Command prompt Command options and arguments DOS and Unix common commands The Job of the Shell 12/19/2024 2 Goals of the chapter After completing lesson, you will be able to: Describe the importance of computers in today’s world. Identify the main parts of a computer. Identify the primary hardware components of a computer. Define an operating system and its role. Define the term program. Explain what is meant by data. Define the term network, and identify the benefits of networking. Define the term Internet. Exercise common Unix commands 12/19/2024 3  The Role of Computers In Business and Industry In Publication Field In Education Field In Government Organizations In Medical Field In Science Field In Entertainment Field 12/19/2024 4  Parts of a Computer 1. Input Devices (Keyboard, Mouse, etc.) 2.Output Devices (Monitor, Speakers, etc.) 3.Central Processing Unit (CPU) and memory 4.Motherboard (Circuit Board) 5.Expansion Cards (Video Card, Sound Card, or NIC) 6.Hard Drive Ports and Connections (USB, Firewire, etc.) 12/19/2024 5  Basic Personal Computer System A computer system consists of hardware and software components. Hardware is the physical equipment such as the case, storage drives, keyboards, monitors, cables, speakers, and printers. Software is the operating system and programs. The operating system instructs the computer how to operate. Programs or applications perform different functions. 12/19/2024 6  Computer Cases and Power Supplies Computer case Provides protection and support for internal components. Should be durable, easy to service, and have enough room for expansion. Power supply Converts AC power from the wall socket into DC. Must provide enough power for the installed components and future additions. 12/19/2024 7  Power Supplies The power supply converts alternating-current (AC) power coming from a wall outlet into direct-current (DC) power, which is a lower voltage. DC power is required for all of the components inside the computer. Cables, connectors, and components are designed to fit together comfortably. Never force any connector or component. 12/19/2024 8  Four Basic Units of Electricity Voltage (V): is a measure of the force required to push electrons through a circuit. Voltage is measured in volts. A computer power supply usually produces several different voltages. Current (I): is a measure of the amount of electrons going through a circuit. Current is measured in amperes, or amps (A). Computer power supplies deliver different amperages for each output voltage. Power (P): is voltage multiplied by current. The measurement is called watts (W). Computer power supplies are rated in watts. Resistance (R): is the opposition to the flow of current in a circuit. Resistance is measured in ohms. Lower resistance allows more current to flow through a circuit. Formulas –V = IR –P = VI 12/19/2024 9  Power Supplies CAUTION: Do not open a power supply. Electronic capacitors located inside of a power supply can hold a charge for extended periods of time. 12/19/2024 10  Internal Components 12/19/2024 11  Motherboards The main printed circuit board. Contains the buses, or electrical pathways found in a computer. Buses allow data to travel among the various components. Also known as the system board, the backplane, or the main board. Accommodates CPU, RAM, expansion slots, heat sink/fan assembly, BIOS chip, chip set, sockets, internal and external connectors, various ports, and the embedded wires that interconnect the motherboard components. 12/19/2024 12  Central Processing Unit (CPU) Known as the brain of the computer. Also referred to as the processor. Most important element of a computer system. Executes a program, which is a sequence of stored instructions. 12/19/2024 13  Parts of a Computer Central Processing Unit (CPU) A device that interprets and runs the commands that you give to the computer. Also referred to as the processor. Two major brands are Intel and AMD. Examples: Intel Core 2 Duo, AMD Turion X2 12/19/2024 14  Cooling Systems Electronic components generate heat. Too much heat can damage components. A case fan makes the cooling process more efficient. A heat sink draws heat away from the core of the CPU. A fan on top of the heat sink moves the heat away from the CPU. Fans are dedicated to cool the Graphics-processing unit (GPU). 12/19/2024 15  Parts of a Computer Memory Memory is where information is stored and retrieved by the CPU. There are two main types of memory: –Random Access Memory (RAM): It is the main memory and allows you to temporarily store commands and data. –Read Only Memory (ROM): It is the memory that retains its contents even after the computer is turned off. 12/19/2024 16  Read-only Memory (ROM) Basic instructions for booting the computer and loading the operating system are stored in ROM. The Different types of ROM are: 1. ROM (Read-only memory chips): Information is written to a ROM chip when it is manufactured. A ROM chip cannot be erased or re-written and can become obsolete. 2. PROM (Programmable read-only memory): Information is written to a PROM chip after it is manufactured. A PROM chip cannot be erased or re-written. 3. EPROM (Erasable programmable read-only memory): Information is written to an EPROM chip after it is manufactured. An EPROM chip can be erased with exposure to UV light. Special equipment is required. 4. EEPROM (Electrically erasable programmable read-only memory): Information is written to an EEPROM chip after it is manufactured. EEPROM chips are also called Flash ROMs. An EEPROM chip can be erased and re-written without having to remove the chip from the computer. 12/19/2024 17  Serial Ports and Cables A serial port can be either a DB-9, as shown, or a DB-25 male connector. Serial ports transmit one bit of data at a time. To connect a serial device, such as a modem or printer, a serial cable must be used. A serial cable has a maximum length of 50 feet (15.2 m). 12/19/2024 18  Parallel Ports and Cables Parallel ports can transmit 8 bits of data at one time and use the IEEE 1284 standard. To connect a parallel device, such as a printer, a parallel cable must be used. A parallel cable has a maximum length of 15 feet (4.5 m). 12/19/2024 19  Network Ports and Cables A network port, also known as an RJ-45 port, connects a computer to a network. Standard Ethernet can transmit up to 10 Mbps. Fast Ethernet can transmit up to 100 Mbps. Gigabit Ethernet can transmit up to 1000 Mbps. The maximum length of network cable is 328 feet (100 m). 12/19/2024 20  Input Devices Input devices used to enter data or instructions into a computer: Mouse and Keyboard Digital camera and digital video camera Biometric authentication device Touch screen Scanner 12/19/2024 21  Output Devices Printers, Scanners, and Fax Machines -Printers are output devices that create hard copies of computer files. Other all-in-one type printers are designed to provide multiple services such as printing, fax, and copier functions. Speakers and head phones are output devices for audio signals. –Most computers have audio support either integrated into the motherboard or on an adapter card. –Audio support includes ports that allow input and output of audio signals. Headphones Speakers 12/19/2024 22  Operating System Overview What is OS? What does OS do? Structure of OS Storage Structure Multiprogramming OS services User OS interfaces Computing environment 12/19/2024 23  What is OS? Operating System is a software, which makes a computer to actually work. It is the software the enables all the programs we use. The OS organizes and controls the hardware. OS acts as an interface between the application programs and the machine hardware. Examples: Windows, Linux, Unix and Mac OS, etc., 12/19/2024 24  What OS does? An operating system performs basic tasks such as, controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking and managing file systems. 12/19/2024 25  Structure of Operating System Application Programs System Programs Software (Operating System) HARDWARE 12/19/2024 26  Contd… The structure of OS consists of 4 layers: 1. Hardware provides basic computing resources such as CPU, Main memory, I/O Devices, etc, 2. Software (Operating System) Controls and coordinates use of hardware among various applications and users 12/19/2024 27  Contd… 3. System programs: or System Software are the programs which enable the computer hardware or system to run (without these the computer as a whole or parts of it's functionality would not work). The programs and the file that comprises the operating system are called system software. These files include configuration files, system preferences, system services, libraries of functions and the drivers for the hardware installed on the computer. Examples: include the operating system, device drivers. This layer consists of compilers, Assemblers, linker etc. 12/19/2024 28  Contd… 4.Application programs–or Application Software are the programs written to for specific applications or execution of specific tasks. e.g. Microsoft Word is an application software for word processing. Internet Explorer and Mozilla Firefox are application software written for internet browsing. Computer games are also application programs. Define the ways in which the system resources are used to solve the computing problems of the users: Word processor, web browsers, database systems, video games This is dependent on users need. Ex. Railway reservation system, Bank database management etc., 12/19/2024 29  Open vs Closed Source operating systems Linux : is the most well known Open Source OS and Windows is the most well known Closed Source OS. So what does this mean? Open Source programs are programs where you can see the code (the source), you can edit it, copy it and use as you wish within the confines of an open source license. As a result of this Linux is not developed by one person or one company but uses code developed by thousands of people, working for different organizations all over the world. And as a result there are many different versions (known as distributions) of Linux out there including Ubuntu, Slackwareand Fedora. Android is built using Linux code. Closed Source software doesn't allow people to look at the code or adapt it. Companies normally sell closed source products and you'll have to pay for a copy of Windows. 12/19/2024 30  Home Work 1. is utility software? Give examples? 2.What is the purpose of translator software, give full definitions of the following translator soft-wares. Assembler Compiler Interpreter Linker Loader 3.State which program goes with the definition? System program or application program? Definitions of a program a) Gets installed when the operating system is installed on the computer b) Users often do not interact with system software c) Includes programs such as compilers, debuggers, drivers, assemblers 12/19/2024 31 d) Includes media players, word processors, and spreadsheet programs. Four Components of a Computer System 12/19/2024 32  Four Components of a Computer System 12/19/2024 33  Computer Startup There is a program on the motherboard called the system BIOS(Basic I/O System) BIOS contains low-level I/O software including: Procedures to read the keyboard Procedures to write to the screen See how much RAM is installed 12/19/2024 34  Contd… The bootstrap program is loaded at power-up or reboot. –Typically stored in ROM or EPROM, generally known as firmware. –Initializes all aspects of system –Loads operating system kernel and starts execution. –It is the initial program run when a computer is powered on or booted. 12/19/2024 35  Computer System Organization Computer-system operation –One or more CPUs, device controllers connect through common bus providing access to shared 12/19/2024 36  Computer-System Operation I/O devices and the CPU can execute concurrently. Each device controller is in charge of a particular device type. Each device controller has a local buffer. CPU moves data from/to main memory to/from local buffers I/O is from the device to local buffer of controller. Device controller informs CPU that it has finished its operation by causing an interrupt. 12/19/2024 37  Storage Structure Main memory –The only large storage media that the CPU can access directly. Secondary storage –extension of main memory that provides large nonvolatile storage capacity. Magnetic disks –rigid metal or glass platters covered with magnetic recording material. 12/19/2024 38  Storage Hierarchy Storage systems are organized in hierarchy. –Speed –Cost –Volatility Caching–copying information into faster storage system; main memory can be viewed as a last cache for secondary storage. 12/19/2024 39  Storage-Device Hierarchy 12/19/2024 40  Caching Important principle, performed at many levels in a computer (in hardware, operating system, software) Information in use copied from slower to faster storage temporarily Faster storage (cache) checked first to determine if information is there –If it is, information used directly from the cache (fast) –If not, data copied to cache and used there Cache smaller than storage being cached –Cache management important design problem –Cache size and replacement policy 12/19/2024 41  Performance of Various Levels of Storage Movement between levels of storage hierarchy can be explicit or implicit 12/19/2024 42  Multiprogramming Multiprogramming is a technique to execute number of programs simultaneously by a single processor. In Multiprogramming, number of processes reside in main memory at a time. The OS picks and begins to executes one of the jobs in the main memory. If any I/O wait happened in a process, then CPU switches from that job to another job. Hence CPU is not idle at any time. 12/19/2024 43  Contd… The main memory consists of 5 jobs at a time, the CPU executes one by one. Advantages: Efficient memory utilization. Throughput increases. CPU is never idle, so performance increases. OS Job 1 Job 2 Job 3 Job 4 Job 5 12/19/2024 44  Time Sharing Systems Time sharing, or multitasking, is a logical extension of multiprogramming. Multiple jobs are executed by switching the CPU between them. In this, the CPU time is shared by different processes, so it is called as “Time sharing Systems”. Time slice is defined by the OS, for sharing CPU time between processes. Examples: Multics, Unix, etc., 12/19/2024 45  Operating System Services One set of operating-system services provides functions that are helpful to the user: –User interface -Almost all operating systems have a user interface (UI). Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch. –Program execution -The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error). –I/O operations -A running program may require I/O, which may involve a file or an I/O device. –File-system manipulation -The file system is of particular interest. Obviously, programs need to read and write files and directories, create and delete them, search them, list file Information, permission management. 12/19/2024 46  Cont… –Communications–Processes may exchange information, on the same computer or between computers over a network. Communications may be via shared memory or through message passing (packets moved by the OS). –Error detection –OS needs to be constantly aware of possible errors. May occur in the CPU and memory hardware, in I/O devices, in user program. For each type of error, OS should take the appropriate action to ensure correct and consistent computing. Debugging facilities can greatly enhance the user’s and programmer’s abilities to efficiently use the system. 12/19/2024 47  Cont… Another set of OS functions exists for ensuring the efficient operation of the system itself via resource sharing –Resource allocation -When multiple users or multiple jobs running concurrently, resources must be allocated to each of them. Many types of resources -Some (such as CPU cycles, main memory, and file storage) may have special allocation code, others (such as I/O devices) may have general request and release code. –Accounting -To keep track of which users use how much and what kinds of computer resources. –Protection and security -The owners of information stored in a multiuser or networked computer system may want to control use of that information, concurrent processes should not interfere with each other. Protection: involves ensuring that all access to system resources is controlled. Security : of the system from outsiders requires user authentication, extends to defending external I/O devices from invalid access attempts. If a system is to be protected and secure, precautions must be instituted throughout it. A chain is only as strong as its weakest link. 12/19/2024 48  User Operating System Interface -CLI CLI allows direct command entry. Sometimes implemented in kernel, sometimes by systems program. Primarily fetches a command from user and executes it. –Sometimes commands built-in, sometimes just names of programs. »If the latter, adding new features doesn’t require shell modification. 12/19/2024 49  User Operating System Interface -GUI User-friendly desktop metaphor or symbol interface. –Usually mouse, keyboard, and monitor. –Icons repesent files, programs, actions, etc –Various mouse buttons over objects in the interface cause various actions (provide information, options, execute function, open directory (known as a folder). –Invented at Xerox PARC Many systems now include both CLI and GUI interfaces –Microsoft Windows is GUI with CLI “command” shell –Apple Mac OS X as “Aqua” GUI interface with UNIX kernel underneath and shells available. –Solaris is CLI with optional GUI interfaces (Java Desktop, KDE). 12/19/2024 50  User Operating System Interface Command Line Interface (CLI): The user types commands at a prompt. Graphical User Interface (GUI): The user interacts with menus and icons. 12/19/2024 51  Most operating systems include both a GUI and a CLI. 12/19/2024 52  Compare Operating Systems Terms often used when comparing operating systems: Multi-user–Two or more users can work with programs and share peripheral devices, such as printers, at the same time. Multi-tasking–The computer is capable of operating multiple applications at the same time. Multi-processing–The computer can have two or more central processing units (CPUs) that programs share. Multi-threading–A program can be broken into smaller parts that can be loaded as needed by the operating system. Multi-threading allows individual programs to be multi-tasked. 12/19/2024 53  Operating System Requirements Operating systems require a certain amount of hardware resources. These resources are specified by the manufacturer and include such things as: –Amount of RAM –Hard disk space required –Processor type and speed –Video resolution 12/19/2024 54  Cont… To take advantage of all of the features provided by an OS, additional hardware resources such as sound cards, NICs, modems, microphones, and speakers are generally required. Many of the OS developers test various hardware devices and certify that they are compatible with the operating system. Always confirm that the hardware has been certified to work with the operating system before purchasing and installing it. 12/19/2024 55  How to select an operating system 12/19/2024 56  Installation of an Operating System An OS is installed in a defined section of the hard disk, called a disk partition. There are various methods for installing an OS. The method selected for installation is based on the system hardware, the OS being installed, and user requirements. There are four basic options available for the installation of a new OS: 12/19/2024 57  Cont… Clean Install A clean install is done on a new system or in cases where no upgrade path exists between the current OS and the one being installed. It deletes all data on the partition where the OS is installed and requires application software to be reinstalled. A clean install is also performed when the existing OS installation has become damaged in some way. Upgrade If staying within the same OS platform, it is often possible to do an upgrade. With an upgrade, system configuration settings, applications and data are preserved. It simply replaces the old OS files with the new OS files. 12/19/2024 58  Cont… Multi-boot It is possible to install more than one OS on a computer to create a multi-boot system. Each OS is contained within its own partition and can have its own files and configuration settings. On start-up, the user is presented with a menu to select the desired OS. Only one OS can run at a time and it has full control of the hardware. Virtualization Virtualization is a technique that is often deployed on servers. It enables multiple copies of an OS to be run on a single set of hardware, thus creating many virtual machines. Each virtual machine can be treated as a separate computer. This enables a single physical resource to appear to function as multiple logical resources. 12/19/2024 59  Preparing for OS installation A pre-installation checklist helps ensure that the installation process is successful. 1. Verify that all hardware is certified to work with the selected OS. 2. Verify that the hardware resources meet or exceed the published minimum requirements. 3. Confirm that the appropriate installation medium is available. Current operating systems are usually available on both CD and DVD medium. 4. If the OS is to be installed on a system that already contains data: (a) Use system diagnostic tools and utilities to ensure the current OS installation is in good condition, free of malicious or damaging files and codes; (b) Complete a full backup of all important files. 5. If performing a clean-install, verify that all application software is available for installation. 12/19/2024 60  Cont… Before starting the installation, it is necessary to determine the partition structure that best meets user requirements. One of the techniques available to help protect data is to divide the hard drive into multiple partitions. usually 1 for data 1 for the OS) It is also necessary to determine the type of file system to use. A file system is the method the OS uses to keep track of the files. Commonly used file systems include FAT 16/32, NTFS, HPFS, ext2, ext3. Each OS is designed to work with one or more of these file system types and each file system type offers specific advantages. Careful consideration should be made to the type of file systems supported by the selected OS and the benefits of each. 12/19/2024 61  Prepare a computer to participate in a network Once an OS is installed, the computer can be configured to participate in a network; that means it would be given it an address to be identified. A network is a group of devices, such as computers, that are connected to each other for the purposes of sharing information and resources. Shared resources can include printers, documents and Internet access connections. 12/19/2024 62  Cont… To physically connect to a network, a computer must have a network interface card (NIC). The NIC is a piece of hardware that allows a computer to connect to the network medium. In addition to the physical connection, some configuration of the operating system is required for the computer to participate in the network. Each computer on a network requires an Internet Protocol (IP) address, as well as other information, to identify it. There are three parts to the IP configuration, which must be correct for the computer to send and receive information on the network: –IP address-identifies the computer on the network. –Subnet mask-is used to identify the network on which the computer is connected. –Default gateway-identifies the device that the computer uses to access the Internet or another network. 12/19/2024 63  Cont… Manual IP Configuration:-The IP address entered is referred to as a static address and is permanently assigned to that computer using a Keyboard. Dynamic IP Configuration :-Set up a computer to receive network address dynamically. This allows a computer to request an IP address from a pool of IP addresses assigned by another device within the network (DHCP) 12/19/2024 64  Computer naming In addition to the IP address, some network operating systems make use of names. In this environment each individual system must have a unique name assigned to it. A computer name provides a user friendly name, making it easier for users to connect to shared resources such as folders and printers on other computers. 12/19/2024 65  Networking and Its Benefits New technologies create a new kind of network that delivers more than a single type of service. Unlike dedicated networks, these new converged networks are capable of delivering voice, video and data services over the same communication channel or network structure. 12/19/2024 66  Contd… Networks come in all sizes. They can range from simple networks consisting of two computers, to networks connecting millions of devices. 12/19/2024 67  Contd… In business, large networks can be used to advertise and sell products, order supplies, and communicate with customers. Communication over a network is usually more efficient and less expensive than traditional forms of communication, such as regular mail or long distance phone calls. The Internet is considered a "network of networks" because it is literally made up of thousands of networks that are connected to each other. Here are other uses of a network and the Internet: –Sharing music and video files –Research and on-line learning –Chatting with friends –Planning vacations –Purchasing gifts and supplies 12/19/2024 68  Components of a network There are many components that can be part of a network, for example personal computers, servers, networking devices, and cabling. These components can be grouped into four main categories: –Hosts –Shared peripherals –Networking devices –Networking media 12/19/2024 69  Cont… Hosts: Are devices that send and receive messages directly across the network. Shared peripherals: Are not directly connected to the network, but instead are connected to hosts. The host is then responsible for sharing the peripheral across the network. Hosts have computer software configured to enable people on the network to use the attached peripheral devices. The network devices: as well as networking media are used to interconnect hosts. Some devices can play more than one role, depending on how they are connected. For example: a printer directly connected to a host (local printer) is a peripheral. A printer directly connected to a network device and participates directly in network communications is a host. 12/19/2024 70  The Role of Host computers In modern networks, computer hosts can act as a client, a server, or both. The software installed on the computer determines which role the computer plays. Servers are hosts that have software installed that enable them to provide information, like email or web pages to other hosts on the network. For example, a host requires web server software in order to provide web services to the network. Clients are computer hosts that have software installed that enable them to request and display the information obtained from the server. An example of client software is a web browser, like Internet Explorer. 12/19/2024 71  Peer-to-peer networks Client and server software usually runs on separate computers, but it is also possible for one computer to carry out both roles at the same time. This type of network is called a peer-to-peer network. The simplest peer-to-peer network consist software directly connected computers using a wired or wireless connection. Multiple PC scan also be connected to create alarger peer-to-peer network but this requires a network device,such as a hub 12/19/2024 72  Network Topologies When networks are installed, a physical topology map is created to record where each host is located and how it is connected to the network. The physical topology map also shows where the wiring is installed and the locations of the networking devices that connect the hosts. It is very important to maintain and update physical topology maps to aid future installation and trouble shooting efforts. it is some times necessary to have a logical view of the network topology. A logical topology map groups hosts by how they use the network, no matter where they are physically located. Hostnames, addresses, group information and applications can be recorded on the logical topology map. 12/19/2024 73  Concept of communication (source, destination and channel) All communication methods have three elements in common; the message source, or sender like are people, or electronic devices ,that need to communicate a message to other in dividuals or devices. These can element of communication is the destination ,or receiver.A third element, called a channel, provides the pathway over which the message can travel from source to destination. 12/19/2024 74  What is the Internet The Internet is a network of networks that connects users in every country in the world. There are currently over one billion Internet users world wide. Up to now the networks we have discussed have been controlled by one individual or organization. The Internet is a conglomerate or multinational of networks and is owned by one individual or group. There are, however, several major International organizations that help manage the Internet so that every one uses the same rules. 12/19/2024 75  Internet Service Providers (ISP) Any home, business or organization that wants to connect to the Internet must use an Internet Service Provider (ISP). An ISP is a company that provides the connections and support to access the Internet. It can also provide additional services such as Email and web hosting. ISPs range in size from small to very large and differ in terms of the area they service (they may service an entire country) ISPs also differ in the types of connection technologies and speeds they offer. Examples of well known ISPs include AOL, EarthLink, and Roadrunner. 12/19/2024 76  The ISPs relation with the Internet Describe how you connect to the Internet through the ISP and the ISP’s relationship to the Internet. 12/19/2024 77 Contd… Individual computers and local networks connect to the ISP at a Point of Presence (POP). A POP is the connection point between the ISP's network and the particular geographical region that the POP is servicing. An ISP may have many POPs depending on its size and the area it services. Within an ISP, a network of high-speed routers and switches with multiple links move data between the various POPs. ISPs connect to other ISPs in order to send information beyond the boundaries of their own network. The Internet is made up of very high-speed data links that interconnect ISP POPs and ISPs to each other. These interconnections are part of the very large, high capacity network known as the Internet Backbone. 12/19/2024 78  Options for connecting to the ISP ISPs provide a variety of ways to connect to the Internet, depending on location and desired connection speed. Choices for connection: Dial-Up DSL Satellite Cable modem Leased line 12/19/2024 79  Contd… Each Internet access technology uses a network access device, such as a modem, in order to connect to the ISP. It may be built in to your computer or may be provided by the ISP. The simplest arrangement is a modem that provides a direct connection between a computer and the ISP. However, if multiple computers connect through a single ISP connection, you will need additional networking devices. This includes a switch to connect multiple hosts on a local network, and a router to move packets from your local network to the ISP network. A home networking device, such as an integrated router, can provide these functions, as well as wireless capability, in a single package. The choice of Internet access technologies depends on availability, cost, access device used, media used and the speed of the connection. 12/19/2024 80  Home Work2 1.Write a note and different each of the following networking devices? –Router –Switch –Hub –Bridge 2.What is the difference between hardware(MAC) address and IP address? 3.Different the physical topology from logical topology of a network? 4.Compare and contrast wired and wireless media and come up with clear advantages and disadvantages of each wired and wireless communication media? 5.When and where is better to use GUIOS and CLIOS? 81  END OF CHAPTER- ONE 12/19/2024 82