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Computing Basics

Computing Basics. Honolulu Community College Cisco Academy Training Center Semester 1 Version 2.1.1. Overview. Components of the computer. Role of the computer in networking. Internet is like a tree, and computers are like leaves on the tree.

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Computing Basics

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  1. Computing Basics Honolulu Community College Cisco Academy Training Center Semester 1 Version 2.1.1

  2. Overview • Components of the computer. • Role of the computer in networking. • Internet is like a tree, and computers are like leaves on the tree. • Computers are sources and receivers of information on the Internet. • Computers are an integral part of a network, and they play a vital role in the world of work. • Many business applications like spreadsheets, word processors, browsers, etc.

  3. Major Components of a PC • Small, discrete components: • Transistor • Integrated circuit (IC) • Resistor • Capacitor • LED (light emitting diode)

  4. Major Components of a PC (cont.) • Personal computer subsystems: • CPU (central processing unit) • Memory: • RAM, ROM • CD-ROM drive • Floppy disk drive • Bus • System unit • Expansion slots • Power supply

  5. Major Components of a PC (cont.) • Backplane components: • Backplane • network card (NIC) or LAN adapter • Video card • Sound card • Parallel ports • Serial ports • Mouse port • For a laptop, cards and slots are referred to as PCMCIA.

  6. Information Flow in a Computer • Some important information flow: • Boot instructions (ROM). • Software applications (moved into RAM). • Application information (data) -stored in RAM. • Saved information - from RAM to storage device. • Exported information - from RAM and CPU to external devices. • Almost all data flows in parallel through the bus.

  7. NIC • Provides network communications capabilities. • Also called a LAN adapter. • Communicates serially with network, in parallel with computer. • Requires an IRQ, I/O address, and upper memory addresses (for DOS or Windows). • 3 factors in selecting NIC. • Type of network (Ethernet, Token Ring, or FDDI). • Type of media. • Type of system bus.

  8. Installing a NIC • You may need to install a NIC because: • there is none. • NIC is bad or damaged. • Need to upgrade from 10Mbps (standard Ethernet) to 100Mbps (Fast Ethernet). • Need to alter settings on a NIC using a jumper.

  9. Configuring Network Settings on PC • Computer software - essentially to get the computer to do what you want. • Procedure: • 1.select the NIC for software configuration. • 2.input the correct TCP/IP address. • 3.adjust the display (if necessary). • 4.install and set up the browser. • 5.perform a few other tasks (if necessary).

  10. Web Browser • Software application that interprets html (hypertext markup language). • Two most popular browsers: • Netscape Communicator. • Internet Explorer. • Terms: • Hyperlinks - commands that point to another location in PC or on network. • Plug-ins - special purpose software used to display special or proprietary files in browser.

  11. Binary Number System • Computers use binary signals either "on" or "off", corresponding to 1 or 0. • This is a base 2 or binary number system. • Bits - individual 1 or 0. • Byte - group of 8 bits. • In decimal, multipliers for each digit is a power of 10. • 368 = 3x102 + 6x101 + 8x100 • In binary, multipliers for each bit is a power of 2. • 1101 = 1x23 + 1x22 + 0x21 + 1x20 = 13(decimal).

  12. Binary to Decimal Conversion • Converting binary to decimal is understanding what a abase 2 number system is. • Each bit has a multiplier (power of 2). • Powers of 2 are: 1, 2, 4, 8, 16, 32, 64, 128, etc. • 10011101(binary) = 1x27 + 0x26 + 0x25 + 1x24 + 1x23 + 1x22 +0x21 + 1x20 = 128 + 0 + 0 + 16 + 8 + 4 + 0 + 1 = 157 in decimal.

  13. Decimal to Binary Conversion • Note that any decimal number is made up of a unique sum of powers of 2. • Ex1: 25 decimal = 16 + 8 + 1 • In binary: 11001 (i.e. 1x16 + 1x8 + 0x4 + 0x2 + 1x1) • Ex2: 107 decimal = 64 + 32 + 8 + 2 + 1 • In binary: 1101011 • Note: Curriculum gives a general method to convert any decimal to binary.

  14. Other Binary Calculations • How many different values can you represent with a 5 bit number? • In general: 2n values with n bits. • 25 = 32 different values (from 0 to 31 in decimal). • What is the largest value you can represent with an 8 bit number? • In general, highest value is 2n-1, with n bits. • 28 - 1 = 255 • Note you can represent 256 values with 8 bits (from 0 to 255 in decimal).

  15. What is Networking? • Networking is the interconnection of workstations, peripherals terminals and other devices. • Networking addressed 3 problems: • How to avoid duplication of equipment and resources. • How to communicate efficiently. • How to set up and manage a network. • First networks were LANs (local area networks), in a limited geographical area.

  16. Networking Protocols • Networking protocols are a formal set of rules and conventions, determining how devices communicate on the network. • Protocols are like languages. • Devices must use the same protocol in order to communicate.

  17. Evolution of Networking • Early 1980s - rapid development of networking. • Manufacturers developed their own equipment, leading to problem of compatibility between equipment of different vendors. • Initial networks were LANs, generally using one manufacturer’s equipment. • As business demands on networking grew, networks grew to span large geographical areas, and became WANs (wide area networks). • WANS can connect cities or even countries.

  18. WAN Technologies • Some common WAN technologies are: • modems • ISDN (Integrated Services Digital Network) • DSL (Digital Subscriber Line) • Frame relay • ATM (Asynchronous Transfer Mode) • The T (US) and E (Europe) Carrier Series: • T1, E1, T3, E3, etc. • SONET (Synchronous Optical Network)

  19. Digital Bandwidth • Bandwidth - a measure of how much information can flow from one place to another in a given amount of time. • Bandwidth represents the capacity of network connection (max possible data rate). • Bandwidth is measured in bits per second.

  20. Bandwidth is limited by the media

  21. Bandwidth is limited by the service

  22. Bandwidth is limited by the service

  23. Throughput • The actual data rate you get. • Often far less then the maximum possible digital bandwidth of the medium.

  24. Bandwidth vs Throughput • When you design a network, you consider the theoretical bandwidth. Your network will be no faster than what your media will allow. • When you actually work on networks, you measure throughput and decide if the throughput is adequate for the user.

  25. File Transfer Time Calculations

  26. Calculations • A 10 Mbps channel is used to transfer a 5Mbyte file. What is the fastest time required to transfer the file? • T=S/BW = 5MB(8bits/byte)/10Mbps = 4 secs. • Due to congestion, the throughput of the channel is only 40% of capacity. What is the actual time to transfer the file? • P = throughput = 40%(10Mbps) = 4Mbps. • T= S/P = 5MB(8bits/byte)/4Mbps = 10 sec.

  27. Importance of Bandwidth • It is finite. • It can save money. • It’s a key measure of network design and performance. • It’s a key to understanding the Internet. • Demand for it increases constantly. The End

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