Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Managing Information Technology 6 th Edition CHAPTER 2 COMPUTER HARDWARE

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2 Building Blocks of Information Technology HardwareSoftwareNetworkData

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 3 EVOLUTION OF COMPUTER SYSTEMS

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4 EVOLUTION OF COMPUTER SYSTEMS First Generation of Computers – Vacuum Tubes – Magnetic Drum Memories First Generation ( )

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 5 EVOLUTION OF COMPUTER SYSTEMS Second Generation of Computers – Transistors – Magnetic Core Memories First Generation ( ) Second Generation ( )

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 6 EVOLUTION OF COMPUTER SYSTEMS Third Generation of Computers – Integrated Circuits – Semiconductor Memories – Operating System First Generation ( ) Second Generation ( ) Third Generation (1964-late 1970s)

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7 EVOLUTION OF COMPUTER SYSTEMS Fourth Generation of Computers – Large-Scale Integration (LSI) and Very-Large-Scale Integration (VLSI) Circuits – Communication Between Computers – Multiple Processors in a Single Machine First Generation ( ) Second Generation ( ) Third Generation (1964-late 1970s) Fourth Generation (1980s-present)

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8 EVOLUTION OF COMPUTER SYSTEMS Minicomputers – Same Technologies as Third and Fourth Generations – Smaller Machine Size – Smaller Business and Scientific Applications First Generation ( ) Second Generation ( ) Third Generation (1964-late 1970s) Fourth Generation (1980s-present) Minicomputers (1970s-present)

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9 EVOLUTION OF COMPUTER SYSTEMS Microcomputers – Microprocessors – Single-User Systems First Generation ( ) Second Generation ( ) Third Generation (1964-late 1970s) Fourth Generation (1980s-present) Minicomputers (1970s-present) Microcomputers (late 1970s-present)

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 10 BASIC COMPONENTS OF COMPUTER SYSTEMS

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 11 BASIC COMPONENTS OF COMPUTER SYSTEMS All computers made up of the same set of six building blocks: input, output, memory, arithmetic/logic unit, control unit, and files Control unit and arithmetic/logical unit together known as the central processing unit (CPU)

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 12 BASIC COMPONENTS OF COMPUTER SYSTEMS Device(s) needed to enter data into the computer for it to use in its computations Input

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 13 BASIC COMPONENTS OF COMPUTER SYSTEMS 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 Input

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 14 BASIC COMPONENTS OF COMPUTER SYSTEMS Common input methods – Keyboard: input entered by user through keystrokes – Disk drive: data on disk read into memory – Magnetic ink character recognition (MICR): used to process bank checks – Bar code labeling: scans bar codes on packages or products, and reads into computer Input

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 15 BASIC COMPONENTS OF COMPUTER SYSTEMS Common input methods (cont’d) – Optical character recognition (OCR): directly scans typed, printed, or handwritten material – Imaging: inputs digital form of documents and photos Input

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 16 BASIC COMPONENTS OF COMPUTER SYSTEMS Device(s) needed to produce results in a usable format Output

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17 BASIC COMPONENTS OF COMPUTER SYSTEMS Common output methods – Video display unit: displays output on a screen – Disk drive: output written to disk for retrieval later – Printer: output to paper using various types of printers Output

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 18 BASIC COMPONENTS OF COMPUTER SYSTEMS Common output methods – Computer output microfilm (COM): microfilm generated for archive copies in small space – Voice response units: computer recognizes input, generates verbal response messages Output

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 19 BASIC COMPONENTS OF COMPUTER SYSTEMS Referred to as main memory or primary memory All data flows to and from memory Memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 20 BASIC COMPONENTS OF COMPUTER SYSTEMS Divided into cells – Each has a unique address – Can only store limited amount of data Byte: stores one character of data Word: stores two or more characters of data Memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21 BASIC COMPONENTS OF COMPUTER SYSTEMS Memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 22 BASIC COMPONENTS OF COMPUTER SYSTEMS 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 Memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 23 BASIC COMPONENTS OF COMPUTER SYSTEMS Memory......

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 24 BASIC COMPONENTS OF COMPUTER SYSTEMS Carries out: – Mathematical operations (addition, subtraction, multiplication, division) – Logical operations (number comparisons) Arithmetic/logic unit

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 25 BASIC COMPONENTS OF COMPUTER SYSTEMS Consists of VLSI circuits on a silicon chip Can perform up to billions of operations per second Numbers are taken from memory as input and results are stored in memory as output Arithmetic/logic unit

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 26 BASIC COMPONENTS OF COMPUTER SYSTEMS File devices used to store vast quantities of data Computer files

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 27 BASIC COMPONENTS OF COMPUTER SYSTEMS Main memory is limited, volatile, and expensive File devices, or secondary memory, are used to store additional data that is nonvolatile Main disadvantage is the relatively slow speed File storage devices: – Magnetic tape drives, disk drives, floppy drives – Optical CD or DVD drives Computer files

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 28 BASIC COMPONENTS OF COMPUTER SYSTEMS Sequential Access Files – Records are stored in sequence according to file’s control key – Usually stored on magnetic tape Direct Access Files – Records can be accessed immediately, without regard to physical location – Stored on Direct Access Storage Devices (DASD) Computer files

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 29 BASIC COMPONENTS OF COMPUTER SYSTEMS Types of DASDs: – Fixed (hard) drives – Optical disk storage CD-ROM CD-R CD-RW DVD-ROM DVD-R DVD-RW Computer files

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 30 BASIC COMPONENTS OF COMPUTER SYSTEMS Types of DASDs: – Removable drives Floppy drives Zip drives Keychain drives Computer files

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 31 BASIC COMPONENTS OF COMPUTER SYSTEMS Controls the other five components of the computer system Control unit

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 32 BASIC COMPONENTS OF COMPUTER SYSTEMS Used to take advantage of speed and capacity of other components List of operations, called a program, tells the control unit what to do These operations are read from memory, interpreted, and carried out one at a time (stored-program concept) Control unit

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 33 STORED-PROGRAM CONCEPT Program – A list of what is to be done for an application – Each step or operation is called an instruction Machine language – Form of a program that can be understood by a specific computer model – Consists of operation code and addresses

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 34 STORED-PROGRAM CONCEPT Measure of computer power – Millions of instructions per second (MIPS) – Millions of floating point operations per second (MFLOPS) – Benchmarking involves running a set of real jobs on various machines to compare speed

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 35 STORED-PROGRAM CONCEPT Benchmarking

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 36 EXTENSIONS TO THE BASIC MODEL High-speed, high-cost storage Used as intermediary between control unit and main memory Compensates for speed mismatches built into the computer system Cache memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 37 EXTENSIONS TO THE BASIC MODEL Locality of reference – If a piece of data is used, there is a high probability that a nearby piece of data will be used shortly thereafter Data reuse – Data is retained in cache until it has not been recently referenced Cache memory

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 38 EXTENSIONS TO THE BASIC MODEL Systems that contain more than one processor Dual-processor vs. dual-core – Dual-processor systems contain two physically separate processors in the same box – Dual-core systems contain two complete processors manufactured as part of a single chip Multiprocessor systems

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 39 EXTENSIONS TO THE BASIC MODEL Symmetric multiprocessor (SMP) – All processors are identical and work independently of each other Parallel processor (PP) – Multiple processors work on separate pieces of the same program Massively parallel processor (MPP) – Machines with a large number of parallel processors Multiprocessor systems

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40 TYPES OF COMPUTER SYSTEMS Also called personal computers or PCs Can generally be carried or moved by one person and only have one keyboard and display unit Examples: – Desktop PC – Laptop or notebook – Handheld or palmtop – Tablet PC Microcomputers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 41 TYPES OF COMPUTER SYSTEMS Microcomputers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 42 TYPES OF COMPUTER SYSTEMS Two major types of microcomputers – IBM-compatible PCs – Apple microcomputers Have been put to a myriad of uses – Record-keeping – Word processing – Games – Presentations – Programming Microcomputers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 43 TYPES OF COMPUTER SYSTEMS Broadest category of computer systems Workstations – More powerful microcomputers – Success due to development of the reduced instruction set computing (RISC) chip Minicomputers – Similar to mainframe systems, but less powerful and less expensive – Used for departmental computers, office automation, and servers Midrange systems

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 44 TYPES OF COMPUTER SYSTEMS Subcategories – Low-end midrange systems Essentially high-powered PCs Typically built on Intel Pentium, Celeron, or Xeon processors or AMD Opteron processors Often run Windows Server – High-end midrange systems Powered by RISC processors or top-of-the-line Intel or AMD processors Usually run Linux or some variation of UNIX Midrange systems

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 45 TYPES OF COMPUTER SYSTEMS Subcategories (cont’d) – Similar to minicomputers Better input/output capabilities than workstations Easy-to-use commercial applications software Legacy systems, but those that remain have incorporated RISC processors and UNIX Midrange systems

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 46 TYPES OF COMPUTER SYSTEMS The heart of the computer systems for most major corporations and government agencies Major strength is versatility in applications – Online and batch processing – Standard business applications – Engineering and scientific applications – Network control – Systems development – Web serving Mainframe computers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 47 TYPES OF COMPUTER SYSTEMS Mainframe computers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 48 TYPES OF COMPUTER SYSTEMS Serve as “number-crunchers” Handle problems generated by research scientists High-end supercomputers located in government research laboratories and major universities Fastest supercomputer (IBM Blue Gene/L) incorporates 65,536 processors and can achieve performance of teraflops Supercomputers

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 49 TYPES OF COMPUTER SYSTEMS

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 50 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall