Computers © 2005 Prentice-Hall, Inc. Slide 1

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

Computers Chapter 4 – Inside the Computer Objectives 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 3

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

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

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

Computers Inside the Computer Digital: The Language of Computers Binary (base 2) – confusing for humans; only uses 1’s and 0’s Hexadecimal (base 16) – used to represent numbers using fewer digits A=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 Motherboard Chipset – 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 Connected to the Motherboard: Processor Chipset Memory chips Expansion boards © 2005 Prentice-Hall, Inc. Slide 11

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

Computers Inside the Computer The PC System Unit The Processor: Computer on a Chip Pentium 4 Celeron XeonTM ItaniumTM © 2005 Prentice-Hall, Inc. Slide 13

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

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

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

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

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

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

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

Computers Inside the Computer Other High-Speed Memories ROM (read-only memory) – contains instructions to the computer that the user cannot change 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 Flash Memory Nonvolatile memory – does not lose data in a power outage Easily upgraded 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 Machine language – what a computer actually understands All 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 CISC (complex instruction set computer) – understands many different instructions RISC (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 Instruction Cycle Instruction time (I-time) – instruction is retrieved from memory and decoded Execution 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 Pipelining – 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 PCI (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 Expansion slots – where expansion boards are installed Expansion boards or expansion cards – provide additional capabilities to the computer © 2005 Prentice-Hall, Inc. Slide 28

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

Computers Inside the Computer Buses and Ports USB (universal serial bus) – used to connect peripheral devices to the PC USB 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 Hot plug – USB devices can be attached or removed while the PC is running USB 2.0 – about 40 times faster than original USB © 2005 Prentice-Hall, Inc. Slide 31

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

Computers Inside the Computer Buses and Ports SCSI (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 Serial port – data flows one bit at a time Parallel port – data flows several bits at a time IrDA port or infrared port – data sent by light waves © 2005 Prentice-Hall, Inc. Slide 34

Computers Inside the Computer PC Growth: Adding Capabilities Expansion Boards – placed in expansion slots Graphics adapter Sound Data/voice/fax modem Network interface card (NIC) SCSI interface card Video capture card © 2005 Prentice-Hall, Inc. Slide 35

Computers Inside the Computer PC Cards: PCMCIA Technology PCMCIA card or PC card Usually used on notebook computers Expand RAM NIC Hard-disk cards GPS (global positioning system) © 2005 Prentice-Hall, Inc. Slide 36

Computers Inside the Computer Build Your Own PC Advantages Cheaper (for high-end systems) Meets your requirements Disadvantages No warranty on system No help desk © 2005 Prentice-Hall, Inc. Slide 37

Computers Inside the Computer Describing the Processor and Its Performance Word 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 Gigahertz (GHz) – billions of clock cycles per second Megahertz (MHz) – millions of clock cycles per second © 2005 Prentice-Hall, Inc. Slide 39

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

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

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

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

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

Computers Inside the Computer Processor Design Grid 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