Computers Chapter 4 Inside the Computer 2005 PrenticeHall

Computers Chapter 4 Inside the Computer © 2005 Prentice-Hall, Inc. Slide 2

Computers Chapter 4 – Inside the Computer Objectives ü Understand how data is stored and represented in a computer ü Describe the functions and relationships between internal computer components ü Distinguish processors by word size, speed, and memory capability ü Identify new processor design approaches © 2005 Prentice-Hall, Inc. Slide 3

Computers Inside the Computer Digital: The Language of Computers ü Analog – continuous waveforms ü Digital – data is described using only two states: on and off © 2005 Prentice-Hall, Inc. Slide 4

Computers Inside the Computer Digital: The Language of Computers ü Digitize – to convert data, analog signals, and images into 1’s and 0’s used by computers © 2005 Prentice-Hall, Inc. Slide 5

Computers Inside the Computer Digital: The Language of Computers ü Binary – two-digit numbering system ü 1 represents on ü 0 represents off ü Each 1 or 0 is called a bit ü Bit – short for binary digit © 2005 Prentice-Hall, Inc. Slide 6

Computers Inside the Computer Digital: The Language of Computers üEncoding systems ü ASCII – American Standard Code for Information Interchange ü ANSI – American National Standards Institute ü UNICODE – capable of handling most printed languages © 2005 Prentice-Hall, Inc. Slide 7

Computers Inside the Computer Digital: The Language of Computers ü Byte – collection of bits that represent a character ü ASCII – 7 bits/byte ü ANSI – 8 bits/byte ü UNICODE – 16 bits/byte © 2005 Prentice-Hall, Inc. Slide 8

Computers Inside the Computer Digital: The Language of Computers ü Binary (base 2) – confusing for humans; only uses 1’s and 0’s ü Hexadecimal (base 16) – used to represent numbers using fewer digits üA=10, B=11, C=12, D=13, E=14, F=15 © 2005 Prentice-Hall, Inc. Slide 9

Computers Inside the Computer The PC System Unit ü Motherboard üChipset – group of integrated circuits (IC) that control communication between system components © 2005 Prentice-Hall, Inc. Slide 10

Computers Inside the Computer The PC System Unit ü Connected to the Motherboard: üProcessor üChipset üMemory chips üExpansion boards © 2005 Prentice-Hall, Inc. Slide 11

Computers Inside the Computer The PC System Unit ü Motherboard üSystem bus – permits communication between components üDevice controllers – control peripheral devices © 2005 Prentice-Hall, Inc. Slide 12

Computers Inside the Computer The PC System Unit ü The Processor: Computer on a Chip üPentium 4 üCeleron üXeon. TM üItanium. TM © 2005 Prentice-Hall, Inc. Slide 13

Computers Inside the Computer The PC System Unit ü Central Processing Unit üControl unit üArithmetic and logic unit © 2005 Prentice-Hall, Inc. Slide 14

Computers Inside the Computer Central Processing Unit ü Control unit üReads and interprets instructions üDirects the operation of internal processor components üControls the flow of programs and data in and out of RAM © 2005 Prentice-Hall, Inc. Slide 15

Computers Inside the Computer Central Processing Unit ü Decoder – interprets instructions that have been retrieved from RAM ü Registers – high-speed working storage areas üinstruction register – contains instruction to be executed üprogram register – contains location of next instruction to be executed © 2005 Prentice-Hall, Inc. Slide 16

Computers Inside the Computer Central Processing Unit ü Arithmetic and Logic Unit üPerforms computations üPerforms logical operations (comparisons) üAccumulator – register where answers are stored © 2005 Prentice-Hall, Inc. Slide 17

Computers Inside the Computer RAM: Digital Warehouse ü High-speed holding area for data and programs ü Volatile memory – data is lost if electrical current is not maintained ü Address – specific location in RAM © 2005 Prentice-Hall, Inc. Slide 18

Computers Inside the Computer RAM: Digital Warehouse ü DDR SDRAM – synchronous dynamic RAM ü SIMMs – single in-line memory modules ü DIMMs – dual in-line memory modules © 2005 Prentice-Hall, Inc. Slide 19

Computers Inside the Computer Cache üThroughput – rate at which the computer works üCache Memory – faster than RAM © 2005 Prentice-Hall, Inc. Slide 20

Computers Inside the Computer Other High-Speed Memories ü ROM (read-only memory) – contains instructions to the computer that the user cannot change ü PROM (programmable ROM) – user can store read-only programs and data © 2005 Prentice-Hall, Inc. Slide 21

Computers Inside the Computer Other High-Speed Memories ü Flash Memory üNonvolatile memory – does not lose data in a power outage ü Easily upgraded ü BIOS (Basic Input Output System) – stored in flash memory © 2005 Prentice-Hall, Inc. Slide 22

Computers Inside the Computer The Instruction Set and the Instruction Cycle üMachine language – what a computer actually understands üAll instructions to a computer must be converted to binary © 2005 Prentice-Hall, Inc. Slide 23

Computers Inside the Computer The Instruction Set and the Instruction Cycle üCISC (complex instruction set computer) – understands many different instructions üRISC (reduced instruction set computer) – understands a smaller list of instructions © 2005 Prentice-Hall, Inc. Slide 24

Computers Inside the Computer The Instruction Set and the Instruction Cycle üInstruction time (I-time) – instruction is retrieved from memory and decoded üExecution time (E-time) – instruction is executed and result is placed in memory © 2005 Prentice-Hall, Inc. Slide 25

Computers Inside the Computer The Instruction Set and the Instruction Cycle üPipelining – processor begins working on another instruction before the current instruction is completed © 2005 Prentice-Hall, Inc. Slide 26

Computers Inside the Computer Buses and Ports üPCI (peripheral component interconnect) local bus – allows for circuit boards to connect to the common system bus © 2005 Prentice-Hall, Inc. Slide 27

Computers Inside the Computer Buses and Ports üExpansion slots – where expansion boards are installed üExpansion boards or expansion cards – provide additional capabilities to the computer © 2005 Prentice-Hall, Inc. Slide 28

Computers Inside the Computer Buses and Ports üAGP (accelerated graphics port) bus– speeds up high-resolution 3 -D graphics © 2005 Prentice-Hall, Inc. Slide 29

Computers Inside the Computer Buses and Ports üUSB (universal serial bus) – used to connect peripheral devices to the PC üUSB hub – connects to the USB port and provides additional places to plug USB devices © 2005 Prentice-Hall, Inc. Slide 30

Computers Inside the Computer Buses and Ports üHot plug – USB devices can be attached or removed while the PC is running üUSB 2. 0 – about 40 times faster than original USB © 2005 Prentice-Hall, Inc. Slide 31

Computers Inside the Computer Buses and Ports ü 1394 bus – similar to USB in speed üFire. Wire – Apple terminology üSupports hot plugging © 2005 Prentice-Hall, Inc. Slide 32

Computers Inside the Computer Buses and Ports üSCSI (small computer system interface) or “scuzzy” bus – early alternative to expansion slots in PCs © 2005 Prentice-Hall, Inc. Slide 33

Computers Inside the Computer Legacy and Other PC Ports üSerial port – data flows one bit at a time üParallel port – data flows several bits at a time üIr. DA port or infrared port – data sent by light waves © 2005 Prentice-Hall, Inc. Slide 34

Computers Inside the Computer PC Growth: Adding Capabilities üExpansion Boards – placed in expansion slots üGraphics adapter üSound üData/voice/fax modem üNetwork interface card (NIC) üSCSI interface card üVideo capture card © 2005 Prentice-Hall, Inc. Slide 35

Computers Inside the Computer PC Cards: PCMCIA Technology üPCMCIA card or PC card üUsually used on notebook computers üExpand RAM üNIC üHard-disk cards üGPS (global positioning system) © 2005 Prentice-Hall, Inc. Slide 36

Computers Inside the Computer Build Your Own PC üAdvantages üCheaper (for high-end systems) üMeets your requirements üDisadvantages üNo warranty on system üNo help desk © 2005 Prentice-Hall, Inc. Slide 37

Computers Inside the Computer Describing the Processor and Its Performance üWord or Bus Width – number of bits handled as a unit © 2005 Prentice-Hall, Inc. Slide 38

Computers Inside the Computer Core Speed: GHz, MIPS, and FLOPS üGigahertz (GHz) – billions of clock cycles per second üMegahertz (MHz) – millions of clock cycles per second © 2005 Prentice-Hall, Inc. Slide 39

Computers Inside the Computer Core Speed: GHz, MIPS, and FLOPS üMIPS – millions of instructions per second üFLOPS – floating point operations per second; used to measure speed of supercomputers © 2005 Prentice-Hall, Inc. Slide 40

Computers Inside the Computer Bus Speed üMost processors operate at GHz üMost buses operate at MHz üMajor block to efficiency in a PC © 2005 Prentice-Hall, Inc. Slide 41

Computers Inside the Computer Memory Capacity üMB (megabyte) – approximately 1 million bytes üGB (gigabyte) – approximately 1 billion bytes üTB (terabyte) – approximately 1 trillion bytes © 2005 Prentice-Hall, Inc. Slide 42

Computers Inside the Computer Memory Capacity üKB (kilobytes) – approximately 1000 bytes üKb (kilobit) üMb (megabit) © 2005 Prentice-Hall, Inc. Slide 43

Computers Inside the Computer Processor Design üParallel processing – multiple processors in one computer system üMassively parallel processing (MPP) – parallel processing with thousands of processors © 2005 Prentice-Hall, Inc. Slide 44

Computers Inside the Computer Processor Design üGrid Computing – users on the Internet share their unused computer power © 2005 Prentice-Hall, Inc. Slide 45

Computers Chapter 4 – Inside the Computer Lesson Summary • • Understand how data is stored and represented in a computer Describe the functions and relationships between internal computer components Distinguish processors by word size, speed, and memory capability Identify new processor design approaches © 2005 Prentice-Hall, Inc. Slide 46

Computers: Information Technology in Perspective, 11 e Larry Long and Nancy Long Chapter 5 Storing and Retrieving Information Copyright Prentice Hall, Inc. 46

Objectives • Once you have read and studied this chapter, you will have learned: – The relationship between mass storage and the various types of files. – The various types of magnetic disk devices and media, including organization, principles of operation, maintenance, performance considerations, and security concerns. – The operational capabilities and applications for the various types of optical laser disc storage. – The sources of computer viruses and approaches to protecting your system from these viruses. – Methods and procedures for backing up disk files. Copyright Prentice Hall, Inc. 47

Why this chapter is important to you! • Understanding the types of storage media available will help you to make productive purchasing decisions • Learning about the different types of storage media could help to get you organized Copyright Prentice Hall, Inc. 48

Mass Storage • Programs and information are stored in both RAM and permanent mass storage • Programs and information are retrieved from storage and held in RAM • Types: – Magnetic disk drives – Magnetic tape drives Copyright Prentice Hall, Inc. 49

Files • A file is a recording of information • File types are determined by the program (Word. doc) • Files need organization • We create files, save, files, copy files, download files, compress files, and lots more… Copyright Prentice Hall, Inc. 50

File Management • Files are usually stored in folders or subfolders in Windows • Files can be saved, opened, copied, cut, deleted, and/or renamed Copyright Prentice Hall, Inc. 51

Magnetic Disks • Magnetic disks have random- or directaccess capabilities – Example: choose song three on a CD • They are fast at seeking and retrieving information Copyright Prentice Hall, Inc. 52

Hardware and Storage Media • Two types of magnetic disks: – Interchange • Stored offline • Loaded when needed – Fixed magnetic disk • Permanently installed • Accessible Copyright Prentice Hall, Inc. 53

The Diskette • Interchangeable – Must be protected – Types • Diskette – 3. 5 floppy – Holds 1. 44 MB • Super. Disk or Hi. FD – Holds 120 MB to 200 MB • Zip – Holds 100 MB – Newer: 750 MB Copyright Prentice Hall, Inc. 54

The Hard Disk • Fixed magnetic disk • Hard disk – 1 to 5. 25 inches – 20 GB to 200 GB – Contains 12 disk platters stacked on a spindle – Disk spins over a read/write head – Access arms float over the disk • Portable hard disk – External hard disk • Interchangeable hard disk – Portable hard disk to swap out Copyright Prentice Hall, Inc. 55

Magnetic Disk Organization • Data are stored in tracks – 80 tracks on a diskette – Thousands on hard disks • Sectors are used to store and retrieve data – Recording surface is divided in pie slices – Hard disks have thousands of sectors • Adjacent sectors form clusters – Each cluster is numbered Copyright Prentice Hall, Inc. 56

The File Allocation Table • Cluster information is stored in the VFAT • What happens – OS searches the VFAT for the first cluster – Read/write heads move over the track – Information is read and transmitted – OS looks for other clusters – OS directs to read the additional clusters Copyright Prentice Hall, Inc. 57

Defragmenting • Disk Defragmenter – Consolidates files into contiguous clusters – Minimizes read/write head movement – The read/write heads is the most vulnerable part of the PC system Copyright Prentice Hall, Inc. 58

Formatting • Before using a disk it must be formatted – Formatting creates sectors and tracks to store data – Formatting sets up the VFAT Copyright Prentice Hall, Inc. 59

Disk Speed • Data access is performed in electronic speeds • Moving the read/write heads and spinning the disk can slow speed • Data transfer rate is the rate at which data are read from storage to RAM or written to storage from RAM • Disk caching improves speed Copyright Prentice Hall, Inc. 60

Optical Laser Discs • May replace magnetic and tape storage • Two lasers replace the read/write head Spiraling Track Detector Pit – One writes to the surface – The other reads data from the lightsensitive surface Land Sector Copyright Prentice Hall, Inc. 61

CD-ROM and DVD-ROM • CD-ROM – – Spin off of audio CDs Read-only memory Data cannot be altered Data is stored in the form of pits and lands • DVD-ROM – Pits and lands are packed more densely • Both are cheaper to make and hold a lot of information Copyright Prentice Hall, Inc. 62

Rewritable Optical Laser Disc Options • CD-R – Recordable • CD-RW – Allows users to rewrite just like on a Magnetic disk • DVD-RW – Rewrite capabilities – Little more costly – DVD can read both DVD and CD-ROM formats • FMD-ROM on the way – Holds up to 140 GM Copyright Prentice Hall, Inc. 63

What is the Best Mix of Storage Options? • More storage – More costs • More RAM – More costs • More speed – More costs Copyright Prentice Hall, Inc. 64

Viruses and Virus Protection • A virus program – Infects programs, documents, databases and more – It is man-made – It can hide and reproduce – It can lay dormant and then activate – Anti-virus programs can help Copyright Prentice Hall, Inc. 65

Types of Computer Viruses • Macro viruses – Written into the program macro – Shuts down functions • Worm – A program that makes copies of itself – It will interfere with normal operations Copyright Prentice Hall, Inc. 66

Sources of Computer Viruses • Three primary sources – The Internet • Via downloads and exchanges – Diskettes • Exchanging disks – Computer networks • Can spread from one network to another Copyright Prentice Hall, Inc. 67

Virus Protection • Antivirus program – Must install and keep updated – What it will do: • Delete e-mails that are suspicious • Alert you before opening a file • Scans downloaded files Copyright Prentice Hall, Inc. 68

Backing up Files • Safeguard your contents – Choose a backup plan • Full • Selective • Incremental – Choose your media • • Rewritable Diskettes High-capacity Portable hard disk Server Another PC And more… Copyright Prentice Hall, Inc. 69

Summary • • Mass Storage Files File Management Magnetic Disks Optical Laser Discs Viruses and Virus Protection Backing Up Files Copyright Prentice Hall, Inc. 70