1. CHAPTER 3 COMPUTER SOFTWARE

2. EVOLUTION OF COMPUTER PROGRAMMING
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 was tedious, time-consuming process
Assembly languages (2GL)
Use computer itself to perform many aspects of the programming
Create a machine language program as output, that is then used by the computer’s control unit
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3. EVOLUTION OF COMPUTER PROGRAMMING
First and Second Generation Languages
SOURCE
PROGRAM
OBJECT
PROGRAM
(which can be
directly executed
on computer)
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Figure 3.1 Assembler Translation Process
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4. EVOLUTION OF COMPUTER PROGRAMMING
Third and Fourth Generation Languages
Procedural Languages (3GL)
Generally are machine independent.
Express a step-by-step procedure developed by programmer
Must be compiled or interpreted (translated into machine language)
Include FORTRAN, COBOL, BASIC, PL/1, PASCAL, ADA, and C
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5. SOURCE PROGRAM OBJECT PROGRAM
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Figure 3.2 Compiling and Running
a Procedural Language Program
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6. SOURCE PROGRAM Page 54 Figure 3.3 Interpreting and Running
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Figure 3.3 Interpreting and Running
an Interpretive Language Program
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7. EVOLUTION OF COMPUTER PROGRAMMING
Third and Fourth Generation Languages
Nonprocedural Languages (4GL)
Also referred to as productivity languages
Use more English-like statements for program instructions
Easier to use, write, and less error-prone
Use a built-in interpreter to convert to machine language
Take much longer to execute than 3GLs
Include FOCUS, CA-Ramis, IFPS, and SAS
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8. EVOLUTION OF COMPUTER PROGRAMMING
Third and Fourth Generation Languages
Object-Oriented (Visual) Languages
3GLs with some 4GL features
Built on idea of embedding procedures (methods) in objects, and putting objects together to create an application
Include Smalltalk, C++, Java, and Visual Basic
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Figure 3.4 The Software Iceberg
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9. KEY TYPES OF SOFTWARE Applications software Support software Page 56
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Figure 3.4 The Software Iceberg
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10. APPLICATIONS SOFTWARE
Programs written to accomplish particular tasks
Diverse … some general-purpose and some specific
Examples include:
General ledger accounting
Portfolio management
Sales forecasting
Material requirements planning (MRP)
Electronic mail
Desktop publishing
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11. APPLICATIONS SOFTWARE
Examples of Applications Packages
Peachtree Accounting Complete
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
$300 for single-user version
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12. Page 58 Figure 3.5 “My Business Page” from
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Figure 3.5 “My Business Page” from
Peachtree Complete Accounting
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13. APPLICATIONS SOFTWARE
Personal Productivity Software
Word processing
Spreadsheets
Presentation graphics
Electronic mail and groupware
Database management systems
Desktop publishing
Web browsers
Statistical packages
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14. APPLICATIONS SOFTWARE
Personal Productivity Software
Word processing
Used to create documents for printing
Most popular is Microsoft Word
Others are Corel WordPerfect, Lotus Word Pro, and Sun’s StarOffice Writer
All employ WYSIWYG
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15. APPLICATIONS SOFTWARE
Personal Productivity Software
Spreadsheets
Used to create applications that fit a row-column format
Most popular is Microsoft Excel
Others are Lotus and Corel Quattro Pro
All employ rows, columns, cells, formulas, “what-if” analysis
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16. Page 61 Figure 3.6 Microsoft Excel Spreadsheet
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Figure Microsoft Excel Spreadsheet
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17. APPLICATIONS SOFTWARE
Personal Productivity Software
Database Management Systems
Used to create databases similar to those on larger machines
Most popular is Microsoft Access
Others are FileMaker Pro, Corel Paradox, and Lotus Approach
All employ a relational data model
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18. APPLICATIONS SOFTWARE
Personal Productivity Software
Presentation Graphics
Used to create largely textual business presentations
Most popular is Microsoft PowerPoint
Others are Corel Presentations and Lotus Freelance Graphics
All allow embedding of clip art, photos, graphs, and other media
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19. APPLICATIONS SOFTWARE
Personal Productivity Software
World Wide Web Browsers
Used to access information on the Web
Requires ISP service to link PC to Internet
Create documents for printing
Most popular are Internet Explorer and Netscape Navigator … both free!
Both employ standard hypertext-based approach (way to link text and media objects to each other)
Use pull technology – browser requests a Web page before it is sent to desktop
Use push technology – data sent to client without requesting it (such as )
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20. APPLICATIONS SOFTWARE
Personal Productivity Software
Electronic Mail
Preferred way of communicating in business today
Easy to use and precise
Groupware
Incorporates and other productivity features, such as calendaring, scheduling, and document sharing
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21. APPLICATIONS SOFTWARE
Personal Productivity Software
Office Suites
Popular software applications bundled together and sold as a single package (suite)
Used for home or office
Most popular is Microsoft Office
Others are Corel WordPerfect Office, Lotus SmartSuite, and Sun StarOffice
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22. APPLICATIONS SOFTWARE
Personal Productivity Software
Microsoft Office 2003
Edition
Applications
Purpose
Retail price
Standard
Word
Excel
PowerPoint
Outlook
Word processing
Spreadsheets
Presentation graphics
, scheduling
$399
Small Business
Adds:
Publisher
Desktop publishing
$449
Professional
Access
Database management
$499
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23. SUPPORT SOFTWARE The Operating System Operating system –
complex program that controls operation of computer hardware and coordinates other software
User communicates with operating system software to control hardware and software resources
Communication made easier with a graphical user interface (GUI) feature
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24. SUPPORT SOFTWARE The Operating System Job Control Language (JCL) –
keyed instructions from the computer user to communicate with the operating system
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25. SUPPORT SOFTWARE 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
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26. SUPPORT SOFTWARE Virtual Memory The Operating System
Concerned with management of main memory
Makes it appear more memory available than actually is
Used only on larger computers
Permits multiprogramming to operate more efficiently
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27. SUPPORT SOFTWARE The Operating System Multiprocessing –
work that takes place when two or more CPUs are installed on same computer system
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28. SUPPORT SOFTWARE Sources of Operating Systems The Operating System
Microcomputers: MS-DOS, PC-DOS, Windows XP
Midrange systems: OS/400
Large systems: VM and MVS
Proprietary systems –
most popular type of operating systems, written for a particular computer hardware configuration
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29. SUPPORT SOFTWARE Sources of Operating Systems Examples: UNIX and Linux
The Operating System
Sources of Operating Systems
Examples: UNIX and Linux
Open systems –
not tied to any particular computer system or hardware manufacturer – will run on virtually any computer system
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30. SUPPORT SOFTWARE Sources of Operating Systems
The Operating System
Sources of Operating Systems
Enhanced operating system to allow for
sharing disk drives and printers
handling server side of client/server applications
Network operating systems (NOS) –
software running on a server that manages network resources and controls the operation of a network
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31. SUPPORT SOFTWARE Sources of Operating Systems Major players include:
The Operating System
Sources of Operating Systems
Major players include:
UNIX and Linux
Microsoft Windows NT, 2000 Server, 2003 Server
Novell NetWare
Network operating systems (NOS) –
software running on a server that manages network resources and controls the operation of a network
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32. SUPPORT SOFTWARE Procedural languages (3GL) Require logical thinking
Third Generation Languages
Procedural languages (3GL)
Require logical thinking
Entail development of a detailed step-by-step procedure
Can be developed using structured programming
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33. SUPPORT SOFTWARE Advantages: Program logic easier to follow
Third Generation Languages
Structured programs –
divided into modules, where each has one entry and one exit point
Advantages:
Program logic easier to follow
Maintenance and correction easier and faster
Do not use GO TO logic
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34. SUPPORT SOFTWARE Third Generation Languages Page 70
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Table Stages in the Program
Development Process
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35. SUPPORT SOFTWARE Most popular procedural languages: BASIC C COBOL
Third Generation Languages
Most popular procedural languages:
BASIC C
COBOL
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36. Page 71 Figure 3.9 BASIC Program
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Figure BASIC Program
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37. © 2005 Pearson Prentice-Hall Chapter 3 - 37
Figure C Program
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38. Page 73 Figure 3.11 COBOL Program
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Figure COBOL Program
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39. Page 73 Figure 3.11 COBOL Program
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Figure COBOL Program
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40. Page 74 Figure 3.11 COBOL Program
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Figure COBOL Program
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41. SUPPORT SOFTWARE Other procedural languages: FORTRAN PL/1 PASCAL ADA
Third Generation Languages
Other procedural languages:
FORTRAN
PL/1
PASCAL
ADA
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42. SUPPORT SOFTWARE Nonprocedural languages:
Fourth Generation Languages
Nonprocedural languages:
Use very high-level instructions
Require fewer instructions
Easier to write, modify, understand
Example: FOCUS
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43. Page 76 Figure 3.12 FOCUS Program and Output
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Figure FOCUS Program and Output
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44. SUPPORT SOFTWARE Most popular: HTML: used to create Web pages
Markup Languages
Most popular:
HTML: used to create Web pages
XML: used to facilitate data interchange among Web applications
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45. SUPPORT SOFTWARE Requires more computing power Has built-in GUI
Object-Oriented Programming
Requires more computing power
Has built-in GUI
Neither 3GL nor 4GL … new paradigm
Creates objects only once and stores for reuse
Object examples:
Text box, check box, entity in an organization
Languages:
Smalltalk, C++, Java, Visual Basic.NET
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46. Page 80 Figure 3.13A Visual Basic Program
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Figure 3.13A Visual Basic Program
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47. Page 81 Figure 3.13B Visual Basic Screen Layout
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Figure 3.13B Visual Basic Screen Layout
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48. SUPPORT SOFTWARE HTML Server-side programming languages:
Languages for Developing Web Applications
HTML
Server-side programming languages:
Perl
Java Servlets and Java Server Pages
Microsoft Active Server Pages (ASP, ASP.NET)
ColdFusion
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49. Page 84 Figure 3.17 Grocery Store HTML Form
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Figure Grocery Store HTML Form
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50. Grocery Store HTML Form
HTML and ASP.NET code
to accompany
Grocery Store HTML Form
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Figure 3.17
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51. Program to Process Data from Grocery Store HTML Form
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Figure 3.18
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52. Page 86 Figure 3.19 Grocery Store Confirmation Web Page
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Figure Grocery Store
Confirmation Web Page
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53. Code to Generate Confirmation Web Page Page 86 Figure 3.19
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Figure 3.19
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54. SUPPORT SOFTWARE Database Management Systems
DBMS – support software used to create, manage, and protect organizational data
Database – shared collection of logically related data organized to meet organizational needs
Relational DBMS
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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55. SUPPORT SOFTWARE File Organization
Sequential – arranges records physically adjacent and in order by some (usually unique) sort key
Direct – uses key for records placed so that they are rapidly accessed from DASDs
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Figure File Organizations
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56. SUPPORT SOFTWARE File Organization Indexed
Compromise between sequential and direct
Record keys only arranged in sequence in a separate table, along with location of rest of data associated with that key
Popular types include ISAM and VSAM
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Figure File Organizations
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57. Relational DBMSs use this scheme
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Figure Relationship Schemes
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58. SUPPORT SOFTWARE CASE Tools
Computer-aided software engineering (CASE) – collection of software tools to help automate all phases of the software development life cycle
Growth slower than anticipated
Radically changed nature of systems analyst and programmer jobs
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59. SUPPORT SOFTWARE Large computers LANs and WANs
Communications Interface Software
Large computers
need to control workstations and terminals
Example software: IBM’s CICS, TSO, and CMS
LANs and WANs
Need to connect to the Internet
Web browsers
Telenet
File Transfer Protocol (FTP)
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60. THE CHANGING NATURE OF SOFTWARE
More complexity of hardware/software arrangements
Less concern with machine efficiency
More purchased applications
More programming using object-oriented and visual languages
More emphasis on applications that run on intranets and the Internet
More user development
More use of personal productivity software
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61. THE SOFTWARE COMPONENT OF THE INFORMATION SYSTEMS INDUSTRY
More complexity of hardware/software arrangements
Less concern with machine efficiency
More purchased applications
More programming using object-oriented and visual languages
More emphasis on applications that run on intranets and the Internet
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