CHAPTER 2 COMPUTER SYSTEMS

EVOLUTION OF COMPUTER SYSTEMS First Generation of Computers Vacuum tubes 1946-1959 © 2005 Pearson Prentice-Hall Chapter 2 - 2 Page 24

EVOLUTION OF COMPUTER SYSTEMS Second Generation of Computers Vacuum tubes Transistors 1946-1959 1957-1963 © 2005 Pearson Prentice-Hall Chapter 2 - 3 Page 24

EVOLUTION OF COMPUTER SYSTEMS Third Generation of Computers Vacuum tubes Transistors Integrated circuits 1946-1959 1957-1963 1964-1979 © 2005 Pearson Prentice-Hall Chapter 2 - 4 Page 25

EVOLUTION OF COMPUTER SYSTEMS Fourth Generation of Computers Vacuum tubes Transistors Integrated circuits VLSI (very-large-scale integrated) circuits 1946-1959 1957-1963 1964-1979 1980 - present © 2005 Pearson Prentice-Hall Chapter 2 - 5 Page 25

EVOLUTION OF COMPUTER SYSTEMS The Development of Minicomputers Data General DEC Hewlett-Packard IBM 1946-1959 1957-1963 1964-1979 1980 - present © 2005 Pearson Prentice-Hall Chapter 2 - 6 Page 26

EVOLUTION OF COMPUTER SYSTEMS The Development of Microcomputers Apple IBM PC 1981 1946-1959 1957-1963 1964-1979 1980 - present © 2005 Pearson Prentice-Hall Chapter 2 - 7 Page 26

BASIC COMPONENTS OF COMPUTER SYSTEMS © 2005 Pearson Prentice-Hall Chapter 2 - 8 Page 26

Page 26-27 Table 2.1 Evolution of Intel Microprocessor © 2005 Pearson Prentice-Hall Chapter 2 - 9 Table 2.1 Evolution of Intel Microprocessor Page 26-27

BASIC COMPONENTS OF COMPUTER SYSTEMS Underlying Structure © 2005 Pearson Prentice-Hall Chapter 2 - 10 Figure 2.4 Logical Structure of Digital Computers Page 28

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output © 2005 Pearson Prentice-Hall Chapter 2 - 11

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output Terminal Simpler than a PC Designed strictly for input and output Has keyboard and screen Does not have a processor Connected to computer with telecommunication line Allows user to key data directly into computer © 2005 Pearson Prentice-Hall Chapter 2 - 12 Page 28

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output Terminal Special types: Point-of-sale (retail) ATMs (banking) © 2005 Pearson Prentice-Hall Chapter 2 - 13 Page 28

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output Common input methods: Magnetic ink character recognition (MICR) – used to process bank checks Optical character recognition (OCR) – directly scans typed, printed, or handwritten material Imaging – inputs digital form of documents and photos Bar code labeling – scans bar codes on packages or products, and reads into computer © 2005 Pearson Prentice-Hall Chapter 2 - 14 Page 29

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output Common output methods: Print – output to paper using various types of printers Computer output microfilm (COM) – microfilm generated for archive copies in small space Voice response units – computer recognizes input, generates verbal response messages © 2005 Pearson Prentice-Hall Chapter 2 - 15 Page 29

BASIC COMPONENTS OF COMPUTER SYSTEMS Input/Output Of interest … Multimedia – relatively new term for computer input and output in the form of text, graphics, sound, still images, animations, and/or video © 2005 Pearson Prentice-Hall Chapter 2 - 16 Page 29

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Memory © 2005 Pearson Prentice-Hall Chapter 2 - 17

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Memory Memory All data flows to and from memory Divided into cells: Each has a unique address Memory cell types: Byte – stores one character of data Word – stores two or more characters of data © 2005 Pearson Prentice-Hall Chapter 2 - 18 Page 31

BASIC COMPONENTS OF COMPUTER SYSTEMS Bits and Coding Schemes Each memory cell is a set of circuits Each circuit is on or off (represented by 1 or 0) Each circuit corresponds to a bit (binary digit) Most computers – 8 bits (circuits) represents a character (byte) 2 common bit coding schemes used today: ASCII EBCDIC © 2005 Pearson Prentice-Hall Chapter 2 - 19 Page 32

Bits and Coding Schemes . . . . . . © 2005 Pearson Prentice-Hall Chapter 2 - 20 Figure 2.4 Computer Coding Schemes Page 32

BASIC COMPONENTS OF COMPUTER SYSTEMS Arithmetic/Logical Unit © 2005 Pearson Prentice-Hall Chapter 2 - 21

BASIC COMPONENTS OF COMPUTER SYSTEMS Arithmetic/Logical Unit Consists of VLSI circuits on a silicon chip Carries out: arithmetic – add, subtract, multiply, divide … logical operations – comparing two numbers © 2005 Pearson Prentice-Hall Chapter 2 - 22 Page 33

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files © 2005 Pearson Prentice-Hall Chapter 2 - 23

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files When power is off, everything stored in memory is lost Computer files are used to store data long term File storage devices: Magnetic tape drives, disk drives, floppy drives Optical CD or DVD drives © 2005 Pearson Prentice-Hall Chapter 2 - 24 Page 33

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files Sequential access files Usually stored on magnetic tape drives Direct access files Stored on Direct Access Storage Devices (DASD) - magnetic disk drives © 2005 Pearson Prentice-Hall Chapter 2 - 25 Page 34

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files Types of DASD Fixed (hard) drives © 2005 Pearson Prentice-Hall Chapter 2 - 26 Figure 2.7 Diagram of a Magnetic Disk Drive Page 34

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files Types of DASD Removable: Floppy drives Zip drives Newest: portable DASD for PCs – keychain drive © 2005 Pearson Prentice-Hall Chapter 2 - 27 Figure 2.8 Iomega’s Mini USB Keychain Drive Page 34

BASIC COMPONENTS OF COMPUTER SYSTEMS Computer Files Newer type of DASD Optical Disk Storage CD-ROM 700 megabytes read-only CD-R recordable CD-RW rewritable DVD-ROM 4.7 gigabytes read-only DVD-R recordable DVD-RW rewritable © 2005 Pearson Prentice-Hall Chapter 2 - 28 Page 36

BASIC COMPONENTS OF COMPUTER SYSTEMS Control Unit © 2005 Pearson Prentice-Hall Chapter 2 - 29

BASIC COMPONENTS OF COMPUTER SYSTEMS Control Unit Controls computer to take advantage of speed and capacity of other components Directed by list of operations (program) that tells control unit what to do Uses the stored-program concept © 2005 Pearson Prentice-Hall Chapter 2 - 30 Page 36

THE STORED-PROGRAM CONCEPT Program – list of what computer needs to do for an application Instruction – each individual step or operation in a program Control unit – carries out one step or instruction at a time at electronic speed © 2005 Pearson Prentice-Hall Chapter 2 - 31 Page 37

THE STORED-PROGRAM CONCEPT Note: One of the primary measures of power of computers is the number of instructions it can execute in a given period MIPS – millions of instructions per second executed by the control unit MFLOPS – millions of floating point operations per second © 2005 Pearson Prentice-Hall Chapter 2 - 32 Page 38

THE STORED-PROGRAM CONCEPT Top Seven Desktop PCs – Power System © 2005 Pearson Prentice-Hall Chapter 2 - 33 Table 2.2 Benchmarking Page 39

EXTENSIONS TO THE BASIC MODEL Communications within the Computer System Terminals Magnetic Tape Units Magnetic Disk Units © 2005 Pearson Prentice-Hall Chapter 2 - 34 Figure 2.9 Data Channels and Controllers Page 40

EXTENSIONS TO THE BASIC MODEL Cache Memory High-speed storage to temporarily hold data from main memory waiting to be processed Entire blocks of data moved at one time into cache Enables CPU to execute much faster Also incorporated into DASD controllers © 2005 Pearson Prentice-Hall Chapter 2 - 35 Figure 2.10 Cache Memory Page 40

EXTENSIONS TO THE BASIC MODEL Multiple Processor Configurations Multiprocessor Symmetric multiprocessor (SMP) Vector facility Parallel processor (PP) Massively parallel processor (MPP) © 2005 Pearson Prentice-Hall Chapter 2 - 36 Page 41-42

TYPES OF COMPUTER SYSTEMS Microcomputers Cost in $ MFLOPS Major Vendors Primary Uses 200-3,000 20-400 IBM, Dell, Hewlett-Packard, Gateway, Fujitsu, Toshiba Personal computing Client in client/server applications Web client Small business processing © 2005 Pearson Prentice-Hall Chapter 2 - 37 Page 43-44

TYPES OF COMPUTER SYSTEMS Workstation/Midrange Systems Cost in $ MFLOPS Major Vendors Primary Uses 3,000-1,000,000 40-4,000 IBM, Dell, Hewlett-Packard, Gateway, NEC, NCR, Fujitsu, Toshiba, Sun Microsystems Departmental computing Specific applications (office automation, CAD, other graphics) Midsized business general processing Server in client/server applications Web server, file server, LAN server © 2005 Pearson Prentice-Hall Chapter 2 - 38 Page 44-48

TYPES OF COMPUTER SYSTEMS Mainframe Computers Cost in $ MFLOPS Major Vendors Primary Uses 1,000,000 -20,000,000 200 -8,000 IBM, Fujitsu, Groupe Bull, Unisys Large business general processing Server in client/server applications Large Web server Widest range of applications © 2005 Pearson Prentice-Hall Chapter 2 - 39 Page 48-49

TYPES OF COMPUTER SYSTEMS Supercomputers Cost in $ MFLOPS Major Vendors Primary Uses 1,000,000 -100,000,000 4,000 -100,000,000 IBM, Hewlett-Packard, Dell, Hitachi, Cray, NEC Numerically intensive scientific calculations Very large Web server © 2005 Pearson Prentice-Hall Chapter 2 - 40 Page 49