brown mit7 ch02

MANAGING INFORMATION TECHNOLOGY
7th EDITION
CHAPTER 2
COMPUTER SYSTEMS
-HARDWARE
-SOFTWARE

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HARDWARE

Building Blocks of Information Technology

Hardware

Chapter 2

Software

Chapter 2

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Networks

Chapter 3

Data

Chapter 4

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COMPUTER SYSTEMS
• Hardware:
Physical pieces of a computer system

• Software:
Set of programs that control the operations of a computer

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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)

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BASIC COMPONENTS OF COMPUTER SYSTEMS

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EVOLUTION OF COMPUTER SYSTEMS

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Watson Supercomputer

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Sequoia – One of the fastest computers

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EVOLUTION OF COMPUTER SYSTEMS
• First Generation of Computers
• Vacuum Tubes
• Magnetic Drum Memories

First Generation
(1946-1959)

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EVOLUTION OF COMPUTER SYSTEMS
• Second Generation of Computers
• Transistors
• Magnetic Core Memories

First Generation
(1946-1959)

Second
Generation
(1959-1964)

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Single Transistor

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EVOLUTION OF COMPUTER SYSTEMS
• Third Generation of Computers
• Integrated Circuits
• Semiconductor Memories
• Operating System

First Generation
(1946-1959)

Second
Generation
(1959-1964)

Third Generation
(1964-late
1970s)

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Input:
• Device(s) needed to enter data into the computer for it to use in computations and comparisons Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Input: What is the difference between a terminal and a PC?
• Terminal
-

Designed strictly for input and output
Has keyboard and screen
Does not have a processor
Connected to a computer with a processor via telecommunications - Examples: point-of-sale terminal, ATM
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Common Input Methods:
-

Keyboard: input entered by user through keystrokes
Mouse, stylus, touchpad: alternative to keystrokes
Disk drive or flash drive: data on disk read into memory
Magnetic ink character recognition (MICR): used to process bank checks
- Barcode labeling: scans barcodes on packages or products, and reads into computer
- Optical character recognition (OCR): directly scans typed, printed, or handwritten material
- Imaging: inputs digital form of documents and photos
Keyboard
Disk Drive
Barcode
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Output:
• Device(s) needed to produce results in a usable format

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Common Output Methods:
- Video display unit: displays output on a screen
- Disk drive or flash drive: output written to disk for storage
- Printer: output to paper (various types of printers)
- Computer output microfilm (COM): microfilm generated for archive copies in small space
- Voice response units: computer-generated verbal response messages Video Display
Disk Drive
Microfilm
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:
• Referred to as main memory or primary memory
• All data flows to and from memory • Divide 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
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Memory:
•
•
•
•
•

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

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Arithmetic/Logical Unit:
• Carries out:
- Mathematical operations
(addition, subtraction, multiplication, division)
- Logical operations
(number comparisons)

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Arithmetic/Logical Unit:
• 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

ALU Circuits
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BASIC COMPONENTS OF COMPUTER SYSTEMS
Computer files:
• File devices used to store vast quantities of data
• Main memory is limited, volatile and expensive
• Advantages:
- File devices or secondary memory are used to store additional data that is nonvolatile

• Disadvantages:
- It has relatively slow speed

• Storage Devices:
-

Magnetic tape drives, disk drives, floppy drives
Optical CD or DVD drives

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Types of Computer files:
• 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)

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DIRECT ACCESS STORAGE DEVICES
• Types of DASD:
• Fixed (hard) drives
• Optical disk storage
- CD-ROM
- CD-R
- CD-RW

- DVD-ROM
- DVD-R
- DVD-RW

• Removable drives
- Floppy Drives
- Zip Drives
- Flash (keychain) Drives

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BASIC COMPONENTS OF COMPUTER SYSTEMS
Control unit:
• Controls the other five components of the computer system • 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 (storedprogram concept)

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STORED-PROGRAM CONCEPT
• Computer Program
- A list of what is to be done for an application
- Each step or operation is called an instruction
• Machine Language
- Computer program written for specific computer model
- Program executed by control unit; consists of operation code and addresses • Measure of Computer Power
- Millions of instructions per second (MIPS)
- Millions of floating point operations per second (MFLOPS)
• Benchmarking is used to compare speed for running a set of jobs on different machines
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TYPES OF COMPUTER SYSTEMS

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Table 2.1

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TYPES OF COMPUTER SYSTEMS
Microcomputers:
• For personal computing
• 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 personal digital assistant (PDA)
- Tablet PC

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TYPES OF COMPUTER SYSTEMS
Microcomputers:

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TYPES OF COMPUTER SYSTEMS
Microcomputers, continued:
• Two major microcomputer platforms
- IBM-compatible PCs (personal computers)
- Apple microcomputers (does not use Windows OS)
• Have been put to a myriad of uses
- Record-keeping
- Word processing
- Presentations
- Programming
- and a “client” in a client/server system
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TYPES OF COMPUTER SYSTEMS
Midrange systems:
• In 1980s, included 2 types of computer systems
1. Workstations
- Microcomputers with more powerful chips than PCs
- Reduced instruction set computing (RISC) chip yielded greater performance because it was specialized
2. Minicomputers
- Less powerful and less expensive than mainframe systems
- Used for departmental computers & office automation
Midrange Systems
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TYPES OF COMPUTER SYSTEMS
Midrange systems - today:
• Servers for client/server applications, Web server, etc.
- Low-end

- Essentially high-powered PCs
- Typically built on Intel Pentium, Celeron, Xeon or AMD processors - Often run Windows Server software

- High-end
- Powered by RISC processors or top-of-the-line Intel or
AMD processors
- Usually run Linux or some variation of UNIX
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TYPES OF COMPUTER SYSTEMS
Mainframe Computers:
• Computer platforms for most major corporations and government agencies
• Major strength is versatility in application processing
- Online and batch processing
- Integrated enterprise systems
- Engineering and scientific applications
- Network control
- Systems development environment (not production)
- Web server
• Major players today: IBM, Fujitsu, Unisys
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TYPES OF COMPUTER SYSTEMS
Supercomputers:
• “Number-crunchers” at 250K MFLOPS
• Handle problems generated by research scientists
• High-end supercomputers located in government, R&D labs, major universities
• Cost: $1 - $100 million
• One of fastest supercomputers (IBM Blue Gene/P):
294,912 processors and can achieve speed of 1 petaflop

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SOFTWARE

Chapter 2

Chapter 2

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Chapter 3

Chapter 4

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TWO CATEGORIES OF SOFTWARE
1. Applications software
2. Support software

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APPLICATIONS SOFTWARE
• Programs written to accomplish particular business tasks: accounting, payroll, inventory, sales invoicing, etc.
• Programs that users interact with
• Software for standard applications typically purchased from a vendor • Software for applications unique to the organization typically developed internally or via a vendor contract
• Includes personal productivity software by knowledge workers
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APPLICATIONS SOFTWARE EXAMPLE
• Accounting Software Package:
- Commercial accounting package for smaller businesses
- Includes general ledger, accounts receivable, accounts payable, inventory, payroll, time and billing, job costing, fixed asset accounting, and analysis and reporting tools
- Price: $500 for single-user version

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APPLICATIONS SOFTWARE EXAMPLE
Personal Productivity Software may be purchased as a software suite
- Word Processing
- Spreadsheets
- Database Management Systems
- Presentation Graphics
- Electronic Mail and Groupware

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APPLICATIONS SOFTWARE
Personal Productivity Software
• Database management systems
- Used to create, manage and protect organizational data
- All employ a relational data model
• Database
- Is a shared collection of logically related data organized to meet organizational needs
- MS Office Example : Access

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APPLICATIONS SOFTWARE
Personal Productivity Software
• Presentation graphics
- Used to create slide shows for business presentations
- All allow embedding of clip art, photos, graphs, and other media - MS Office Example: PowerPoint

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APPLICATIONS SOFTWARE
Personal Productivity Software
• Electronic mail
• Groupware
- Incorporates e-mail and other productivity features, such as calendaring, scheduling, and document sharing
- MSOffice Example : Outlook

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APPLICATIONS SOFTWARE
WWW Browsers
• Used to access information (navigate) on the WWW from computers that can access the Internet
- Hypertext-based approach (to link text and media objects to each other)
• Pull technology: browser requests a Web page before it is sent to client
• Push technology: data sent to client without requesting it
(such as e-mail, spam, software patches)
• Examples:
Internet Explorer (Microsoft), Firefox (Mozilla), Safari (Apple)
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SUPPORT SOFTWARE
• Enables applications software to be carried out (run)
• Ensures that computer hardware and software are used efficiently
• Purchased from a hardware or software vendor

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SUPPORT SOFTWARE
Operating System (OS)
• Usually purchased from manufacturer of computer hardware that OS will be used on
• Complex program that controls operation of computer hardware and coordinates other software
• Performance objective is to maximize work done (throughput)
• User communicates with operating system software for input, output, storage, etc.
• Easier to use with graphical user interface (GUI): click on icons instead of enter text commands

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SUPPORT SOFTWARE
Operating System

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SUPPORT SOFTWARE
Operating System Concepts
• Job control language (JCL): instructions used to communicate with the operating system • Multiprogramming: employed on larger machines to overlap input and output operations with processing time, keeping the CPU busy and speeding up execution
• Multitasking: similar to multiprogramming, but employed on microcomputers
• Multithreading: similar to multitasking, but multiple threads within the same program are overlapped
• Multiprocessing: work that takes place when two or more CPUs are installed on same computer system

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SUPPORT SOFTWARE
Operating System Concepts, cont.
• Virtual Memory:
- Optimizes management of main memory by switching in and out portions of programs from DASD
-- Permits multiprogramming to operate more efficiently

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SUPPORT SOFTWARE
Operating System Concepts, cont.
- Proprietary systems: operating systems written for a particular computer hardware configuration
- Microcomputers: MS-DOS, Vista, Windows 7, Mac OS
- Large systems: IBM z/OS and z/VM
- Open systems: not tied to any particular computer system or hardware manufacturer – will run on virtually any computer
• Examples: UNIX and Linux
- IT Platform: set of hardware, software, communications ; OS name usually implies platform
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SUPPORT SOFTWARE
Server or Network Operating System (NOS)
- Software running on a server that manages network resources and controls the operation of a network
- Enhanced operating system that allows for:
- Sharing disk drives and printers
- Handling server side of client/server applications
- Major players include:
- UNIX and Linux
- Microsoft Windows Server

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SUPPORT SOFTWARE
First and Second Generation Languages
• Machine language (1GL)
• Each instruction must be expressed in unique form for a particular computer
• Complete program consists of thousands of instructions
• Programming is a tedious, time-consuming process
• Assembly languages (2GL)
• Easily remembered mnemonic operation codes substituted for machine language operation codes
• Assembler used to convert mnemonic codes to machine language Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall

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SUPPORT SOFTWARE
First and Second Generation Languages

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SUPPORT SOFTWARE
Third Generation Languages
• Procedural languages (3GL)
- Express a step-by-step procedure devised by the programmer - Typically machine independent
- Easier for programmers to learn
- Structured programs: divided into modules, where each has one entry and one exit point
- Must be compiled or interpreted (translated into machine language) ; one 3GL instruction typically translates into many machine language instructions
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SUPPORT SOFTWARE
Compiling and running a 3 GL Program

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SUPPORT SOFTWARE
Developing programs with a 3GL

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SUPPORT SOFTWARE
Third Generation Languages
• Most popular procedural languages & decade introduced
1950s - FORTRAN
1960s - COBOL (COmmon Business Oriented Language)
BASIC
1970s – C

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SUPPORT SOFTWARE
COBOL program example

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SUPPORT SOFTWARE
Fourth Generation Languages
• Nonprocedural languages (4GL)
• Easier to program, but less efficient for computers to run
• Uses more English-like statements for program instructions
• Today may be referred to as a language for business intelligence (BI) application development
•
•
•
•
•

SAS
IBM Cognos
SAP Business Objects
Oracle BI Enterprise Editing Plus
Microsoft SQL 2008 Services (Analysis, Reporting)

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SUPPORT SOFTWARE
Markup Languages
• Employ tags to “mark up” documents
• HTML
- Used to create Web pages
- Consists of special tags that tell the Web browser how to display various elements on a Web page (e.g., bold-faced or italic text, image location, links to other Web pages)
HTML Example

• XML
- Used to facilitate data interchange among Web applications and Web services - Meta language consisting of tags that identify particular data2-61elements

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EXAMPLES
XML Example (tags in brackets)
<Game type= “College Football” date=“9/26/2009”>
Indiana vs. Michigan
<Score team= “Indiana”>33</Score>
<Score team= “Michigan”>36</Score>
</Game>

XML Example
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SUPPORT SOFTWARE
Object-Oriented Programming (OOP) Languages
• Neither 3GL nor 4GL … new paradigm
• Create objects once, store, then reuse
• Object examples:
- Text box, check box
• Most Common Languages:
- C++, Java, Visual Basic.NET, C#

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SUPPORT SOFTWARE
Object-Oriented Programming – Java Example

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SUPPORT SOFTWARE
Languages for Developing Web Applications
• HTML is the most common form of user interface
• Server-side programming languages include:
• PHP
• Java Servlets and Java Server Pages (JSP)
• Microsoft’s Active Server Pages (ASP, ASP.NET)
• Adobe’s ColdFusion

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SUPPORT SOFTWARE
Database Management Systems (DBMS)
- Systems that create, store, and manage modifications to data in a database – and make data accessible for queries, reporting

Data Dictionary/Directory
- Repository for data definitions used by a Database

Data Warehouse
- Very large database or collection of databases for decision support that use a DBMS optimized for analytics (including data mining)
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SUPPORT SOFTWARE
5 DBMS Architectures
1. Hierarchical
•Data are arranged like a top-down organization chart
•Example: IBM Information Management System (IMS)
2. Network
•Data are arranged like cities on a highway system, often with several paths from one piece of data to another
•Example: Computer Associates’ CA-IDMS
3. Relational
•Most common type
•Data arranged in simple tables
•Records related by storing common data in each associated table
•Examples: Microsoft Access and SQL Server, Paradox, DB2, and Ingres

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SUPPORT SOFTWARE
DBMS Architectures
4. Object- Oriented
• Data can be graphics, video, and sound as well as simpler data types
• Attributes and methods are encapsulated in object classes, and relationships between classes can be shown by nesting one class within another
• Examples: Versant Object Database, Progress ObjectStore, and Objectivity/DB
5. Object-relational
• Hybrid approach that can handle complex data types with the simplicity of the relational model
• Examples: Oracle, IBM’s DB2 and Cloudscape, and FFE
Software’s First SQL/J
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SUPPORT SOFTWARE
• Query Language example: SQL/DS Command Language
SELECT ORDER#, CUSTOMER#, CUSTNAME,
ORDER-DATE FROM CUSTOMER, ORDER
WHERE ORDER-DATE> ‘03/12/11’
AND CUSTOMER.CUSTOMER# =
ORDER.CUSTOMER#

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SUPPORT SOFTWARE
Computer-aided software engineering (CASE) Tools
• Collection of software tools to help automate all phases of the software development life cycle to increase productivity of software designers and programmers
• CASE tools for OO development for Unified Modeling
Language ( UML)
- UML = general-purpose notational language for specifying and visualizing complex software, especially large, object-oriented projects

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SUPPORT SOFTWARE
Communications Interface Software
• For Large computers:
• Controls communications between workstations and terminals connected to a network & central computer
• Example: IBM’s Customer Information Control System
(CICS)
• Web Server Software serves Web pages to Web browser
• File Transfer Protocol (FTP) transfers files from one computer system to another
• Utility programs: link together programs & subprograms, merge files (ZIP programs), check for viruses, etc.
FTP
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KEY SOFTWARE TRENDS
• More concern with human efficiency
• More purchased applications software
• More open source support software
• More programming using object-oriented languages
• More emphasis on applications that run on intranets and the Internet
• More user development
• More use of personal productivity software on microcomputers
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IT INDUSTRY TRENDS
Hardware firms
• Have been expanding by adding services (including acquiring established consulting firms)
• Major players:
- US: IBM, Hewlett-Packard, Dell , Apple
- Non US : Acer, Lenovo, Toshiba, Fujitsu, Sony

Software firms
• Have been expanding by developing new products and acquiring smaller software companies
- IBM bought Cognos; SAP bought Business Objects
- Oracle bought PeopleSoft and Salesforce.com
- Oracle also bought Sun (hardware and Java)
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