Brown Mit7 Ch02

Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 2-1

MANAGING INFORMATION TECHNOLOGY

7th EDITION

CHAPTER 2

COMPUTER SYSTEMS

-HARDWARE

-SOFTWARE


HARDWARE

Building Blocks of Information Technology

Hardware Software Networks Data

Chapter 2 Chapter 2 Chapter 3 Chapter 4


COMPUTER SYSTEMS

• Hardware:

Physical pieces of a computer system

• Software:

Set of programs that control the operations of a computer


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)



• Device(s) needed to enter

data into the computer for it

to use in computations and

comparisons

Input:



• 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

Input: What is the difference between a terminal

and a PC?



- 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

Common Input Methods:

Keyboard

Disk Drive

Barcode

http://technabob.com/blog/wp-content/uploads/2007/08/luxeed_keyboard.jpg

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• Device(s) needed to produce

results in a usable format

Output:



- 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

Common Output Methods:

Video Display

Disk Drive

Microfilm

http://snpi.dell.com/snp/images/products/large/320-4087.jpg

http://www.pctechguide.com/images/31HardDrive.jpg

http://www.usacademic.net/images/microfilm.jpg



• 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:

Memory

http://www.microsoft.com/mspress/books/sampchap/6387/0-7356-18550-01.gif



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

Memory:



• Carries out:

- Mathematical operations

(addition, subtraction,

multiplication, division)

- Logical operations

(number comparisons)

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

Arithmetic/Logical Unit:

ALU Circuits

http://www1.cs.columbia.edu/~locasto/teaching/s2006/coms1001/alu.jpg



• 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 non-volatile

• Disadvantages:

- It has relatively slow speed

• Storage Devices:

- Magnetic tape drives, disk drives, floppy drives

- Optical CD or DVD drives

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)

Types of Computer files:


DIRECT ACCESS STORAGE DEVICES

• Types of DASD:

• Fixed (hard) drives

• Optical disk storage - CD-ROM - DVD-ROM

- CD-R - DVD-R

- CD-RW - DVD-RW

• Removable drives

- Floppy Drives

- Zip Drives

- Flash (keychain) Drives



• 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 (stored- program concept)

Control unit:


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


TYPES OF COMPUTER SYSTEMS

Table 2.1



• 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

Microcomputers:



Microcomputers:



• 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

Microcomputers, continued:



• 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:

Midrange Systems

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• 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

Midrange systems - today:



• 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

Mainframe Computers:



• “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

Supercomputers:


SOFTWARE

Building Blocks of Information Technology

Hardware Software Network Data

Chapter 2 Chapter 2 Chapter 3 Chapter 4


TWO CATEGORIES OF SOFTWARE

1. Applications software

2. Support software


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


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


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



• 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




• 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




• Electronic mail

• Groupware

- Incorporates e-mail and other productivity features, such as

calendaring, scheduling, and document sharing

- MSOffice Example : Outlook




• 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)

WWW Browsers


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


SUPPORT SOFTWARE

• 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

Operating System (OS)


SUPPORT SOFTWARE

Operating System


SUPPORT SOFTWARE

• 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

Operating System Concepts


SUPPORT SOFTWARE

• Virtual Memory:

- Optimizes management of main memory by switching in

and out portions of programs from DASD

-- Permits multiprogramming to operate more efficiently

Operating System Concepts, cont.


SUPPORT SOFTWARE

- 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

Operating System Concepts, cont.


SUPPORT SOFTWARE

- 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

Server or Network Operating System (NOS)


SUPPORT SOFTWARE

• 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

First and Second Generation Languages


SUPPORT SOFTWARE

First and Second Generation Languages


SUPPORT SOFTWARE

• 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

Third Generation Languages


SUPPORT SOFTWARE

Compiling and running a 3 GL Program


SUPPORT SOFTWARE

Developing programs with a 3GL


SUPPORT SOFTWARE

• Most popular procedural languages & decade introduced

1950s - FORTRAN

1960s - COBOL (COmmon Business Oriented Language)

BASIC

1970s – C

Third Generation Languages


SUPPORT SOFTWARE

COBOL program example


SUPPORT SOFTWARE

• 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)

Fourth Generation Languages


SUPPORT SOFTWARE

• 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)

• XML

- Used to facilitate data interchange among Web applications and Web services

- Meta language consisting of tags that identify particular data elements

Markup Languages

HTML Example

http://www.ics.heacademy.ac.uk/Events/conf2001/papers/Image55.gif


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

http://www.sqlservercentral.com/articles/SS2K5+-+XML/2826/xml_result1.gif


SUPPORT SOFTWARE

• 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#

Object-Oriented Programming (OOP) Languages


SUPPORT SOFTWARE

Object-Oriented Programming – Java Example


SUPPORT SOFTWARE

• 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

Languages for Developing Web Applications


SUPPORT SOFTWARE

- 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)

Database Management Systems (DBMS)


SUPPORT SOFTWARE

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

5 DBMS Architectures


SUPPORT SOFTWARE

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

DBMS Architectures


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#


SUPPORT SOFTWARE

• 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

Computer-aided software engineering (CASE) Tools


SUPPORT 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.

Communications Interface Software

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


IT INDUSTRY TRENDS

• 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)

Hardware firms


COPYRIGHT

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 © 2012 Pearson Education, Inc.

Publishing as Prentice Hall

Brown Mit7 Ch02

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