Chapter 1 Computing Basics

Electronic Components zCapacitor ystores energy in the form of an electrostatic field zConnector ythe part of a cable that plugs into a port or an interface zIntegrated circuit (IC) ya device made of semiconductor material; it contains many transistors and performs a specific task

Electronic Components zLight emitting diode ya semiconductor device that emits light when a current passes through it zResistor ya device made of a material that opposes the flow of electric current zTransistor ya device that amplifies a signal or opens and closes a circuit

Personal Computer Subsystems zBus ycollection of wires through which data is transmitted from one part of the computer to another; connects all the internal computer components to the CPU (ISA and PCI) zCD-ROM drive ya compact disk read-only memory drive; a device that can read information from a CD-ROM zCentral processing unit (CPU) ythe brains of the computer where most calculations take place

Personal Computer Subsystems zExpansion card ya printed circuit board you can insert into a computer to give it added capabilities zExpansion slot yan opening in a computer where a circuit board can be added zFloppy disk drive ya disk drive that can read or write to floppy disks zHard disk drive ya device that reads and writes data on a hard disk

Personal Computer Subsystems zMicroprocessor ya silicon chip that contains a CPU zMotherboard ythe main printed circuit board of a microprocessor zPower supply ythe component that supplies the power to a computer zPrinted circuit board (PCB) ya thin plate on which chips (ICs) and other electronic components are placed

Personal Computer Subsystems zRandom access memory (RAM) yRAM can have new data written into it and stored data read from it; a drawback of RAM is that it requires electrical power to maintain data storage zRead-only memory (ROM) ycomputer memory on which data has been prerecorded zSystem unit ythe main part of a PC; the system unit includes the chassis, the microprocessor, the main memory, the bus, and the ports

Hard drive interfaces zinterface is the way the drive communicates with the computer; a sort of language that allows the drive and the computer to talk to each other yIDE, SCSI xmost controller circuitry is placed directly on the hard drive

Modems zmodem converts digital data from its local computer into analog tones and pulses that can be sent over the telephone lines ztwo basic types--internal/external

The Power Supply zconverts AC from wall outlet to DC used by computers zcontains fan and AC/DC converter

Backplane Components zBackplane ythe large circuit board that contains slots for expansion cards zInterface ya piece of hardware such as a modem connector that allows two devices to be connected zMouse port ya port designed to connect a mouse to a PC

Backplane Components zNetwork card yan expansion board inserted into a computer so that the computer can be connected to a network zParallel port yan interface capable of transferring more than one bit simultaneously; used to connect external devices such as printers zPort yan interface on a computer to which you can connect an electronic device

Backplane Components zPower cord ya cord used to connect computer to electrical outlet zSerial port yan interface that can be used for serial communi- cation in which only one bit is transmitted at a time zSound card yan expansion card that handles all sound functions zVideo card ya board that plugs into a PC to give it display capabilities

Information Flow Information and electric power are constantly flowing in a PC. zBoot instructions—stored in ROM until they are sent out zSoftware applications—stored in RAM after they are loaded zRAM and ROM—constantly talk to the CPU through the bus zApplication information—stored in RAM while applications are being used zSaved information—flows from RAM to some form of storage device zExported information—flows from RAM and the CPU through the bus and expansion slots to the printer, the video card, the sound card, or the network card

An Idealized Computer

What’s in that box?

Inside a Computer

An Idealized Computer: Information Flow

Network Interface Cards zprinted circuit board that provides network capability to computer zalso called a LAN adapter zcan be designed as an Ethernet, Token Ring, or FDDI card

Network Interface Cards zcommunicate through a serial connection zEach card requires an IRQ, an I/O address, and an upper memory address to work with DOS/WIN95. zTo configure TCP/IP LAN settings in a Windows machine, use the Control Panel icon, Network.

Network Interface Cards zConsiderations: ztype of network (Ethernet, Token Ring, FDDI) ztype of media (CAT5, fiber, wireless) ztype of system bus either PCI/ISA or PCMCIA, which is used on laptops) zTo change a PCs network speed from 10Mbps to 100Mbps, you need to upgrade the NIC.

Web Browsers Plug-ins allow the browser to display proprietary file types.

Plug Ins Flash/Shockwave

Binary Number System zComputer systems only understand “on” and “off” or “1s” and “0s.” zComputer systems use a binary numbering system rather than decimal. zDecimal numbering system uses 10 symbols; they are 0-9. zComputer systems use a Base 2 system bits = 1 byte A bit is a binary digit used in the binary numbering system, either 0 or 1.

Binary Number System

The binary number in Base 2 = (1, 128) = (0, 64) = 0 + (0, 32) = 0 + (1, 16) = 16 + (0, 8) = 0 + (0, 4) = 0 + (0, 2) = 0 + ( 1, 1) = 1 = 145

Binary Number System The decimal number 35 in Base

Binary Number System If the right-most digit is odd, then the number is odd. (255)

Binary Number System If the right-most digit is even, then the number is even. (142)

Networks and Networking zCircuit Switching—a physical end- to-end connection is established and bandwidth is reserved (POTS) zPacket Switching—no physical end-to-end connection and each packet can take a different path (WANS) Circuit Switching vs. Packet Switching

Networks and Networking What is Internetworking?

Networks and Networking The Evolution of Networking

Networks and Networking The Evolution of Internetworking

Networks and Networking The Evolution of Internetworking

Networks and Networking

Ethernet would NOT be a WAN technology.

Digital Bandwidth zis the measure of how much information can flow from one place to another in a given amount of time ztwo common uses zanalog signals zdigital signals zmeasured in bps za major factor in analyzing a network’s performance

Pipe Analogy for Bandwidth

Highway Analogy for Bandwidth

Audio Analogy for Bandwidth

Maximum Bandwidths and Length Limitations Typical MediaMax. Theoretical Bandwidth Max. Physical Distance 50-Ohm coaxial cable (thinnet) Mbps185m 75-Ohm coaxial cable (thicknet) Mbps500m CAT5 UTP10 Mbps100m CAT 5 (Fast Ethernet)100 Mbps100m Multimode Fiber100 Mbps2000m Singlemode Fiber1000 Mbps (1 Gbps)3000m Wireless11 Mbps A few hundred meters

WAN Services and Bandwidths Type of Service Typical UserBandwidth ModemIndividuals56 Kbps ISDN Telecommuters and small businesses 128 Kbps Frame Relay Small institutions and reliable WANs 56 Kbps to 1544 Mbps T1Larger entities1.544 Mbps T3Larger entities Mbps STS-1 (OC-1)Phone companies/Backbones Mbps STS-3 (OC-3)Phone companies/Backbones Mbps STS-48 (OC-48) Phone companies/Backbones Gbps

Throughput zrefers to the actual, measured bandwidth at a specific time of day using specific Internet routes while downloading a specific file za major factor in analyzing a network’s performance

Bandwidth and Throughput zFactors that determine throughput and band- width include: zinternetworking devices ztype of data being transferred ztopology znumber of users zuser’s computer and server computer zpower- and weather-related outages zcongestion

File Transfer Time Calculations