7. INFORMATION SYSTEMS SOFTWARE

1
5. INFORMATION SYSTEMS SOFTWARE
5.1
2
LEARNING OBJECTIVES

• DESCRIBE MAJOR TYPES OF SOFTWARE
• EXAMINE SYSTEM SOFTWARE OPERATING SYSTEMS
• EXPLAIN SOFTWARE EVOLUTION
• ANALYZE MAJOR APPLICATION LANGUAGES
• DESCRIBE APPROACHES TO SOFTWARE DEVELOPMENT
• IDENTIFY SOFTWARE ISSUES

5.2
3
SOFTWARE

• DETAILED INSTRUCTIONS TO CONTROL COMPUTER
  OPERATION
• PROGRAM SET OF INSTRUCTIONS TO THE COMPUTER
• STORED PROGRAM MUST BE IN PRIMARY STORAGE
• SYSTEM SOFTWARE MANAGES COMPUTER RESOURCES
• APPLICATION SOFTWARE SPECIFIC BUSINESS
  APPLICATION

5.3
4
SOFTWARE
APPLICATION SOFTWARE
SYSTEM SOFTWARE
HARDWARE
5.4
5
OPERATING SYSTEM

• MANAGES CONTROLS ACTIVITIES
• ALLOCATION ASSIGNMENT
• SCHEDULING
• MONITORING
• SYSTEM RESIDENCE DEVICE SECONDARY STORAGE
  DEVICE STORING OPERATING SYSTEM

5.5
6
MULTIPROGRAMMING
TRADITIONAL SINGLE-PROGRAM SYSTEM
PROGRAM 1
5.6
7
MULTITASKING

• MULTIPROGRAMMING
• ON A
• SINGLE-USER SYSTEM
• SUCH AS A
• MICROCOMPUTER

5.5
8
VIRTUAL STORAGE

• METHOD OF HANDLING SEVERAL PROGRAMS IN PRIMARY
  STORAGE
• PROGRAM DIVIDED INTO
• FIXED LENGTH PORTIONS (PAGES) OR
• VARIABLE LENGTH (SEGMENTS)
• CURRENT PORTIONS RESIDE IN PRIMARY STORAGE
• PORTIONS SWAPPED OUT WHEN DONE

5.8
9
TIME SHARING

• MANY USERS SHARE LARGE CPU
• TIME IN CPU DIVIDED INTO SLICES (e.g. 2
  MILLISECONDS)
• EACH USER HAS ACCESS TO CPU DURING SLICE
• SINCE CPU IS FAST, CAN DO MUCH DURING TIME SLICE
• USERS JOB SWAPPED OUT AT END OF SLICE

5.9
10
MULTIPROCESSING

• TWO OR MORE PARALLEL PROCESSORS IN SYSTEM
• PROGRAM CAN BE DIVIDED TO BE PROCESSED BY
  MULTIPLE CPUs
• CAN PROCESS LARGE PROGRAMS MORE RAPIDLY

5.10
11
LANGUAGE TRANSLATION

• SOURCE CODE HIGH-LEVEL LANGUAGE INSTRUCTIONS
• COMPILER TRANSLATES HIGH-LEVEL CODE INTO MACHINE
  LANGUAGE
• OBJECT CODE TRANSLATED INSTRUCTIONS READY FOR
  COMPUTER

5.11
12
TRANSLATION PROCESS
5.12
13
GRAPHICAL USER INTERFACE (GUI)

• OPERATING SYSTEM USES
• GRAPHIC ICONS (Icons, Buttons, Bars, Boxes)
• MOUSE
• TO ISSUE COMMANDS
• MAKE SELECTIONS

5.13
14
MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
FEATURES

32-bit operating system GUI Multitasking.
Networking
Windows 98 95
Windows NT 2000
32-bit operating system not limited to Intel
chips. Multitasking Multiprocessing Networking
Windows CE
Paired-down for handheld computers, wireless
communication devices
32-bit. Developed for IBM PS/2. Multitasking
Networking
OS/2
5.14
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MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
FEATURES
UNIX
For powerful Microcomputers, Workstations,
Minicomputers. Multitasking Multi-user
Processing Networking. Portable to various
Computer Platforms
Mac OS
For Macintosh computers. Multitasking. Powerful
Graphics Multimedia
For IBM (PC-DOS) and PC (MS-DOS). Program
Memory 640K
DOS
5.15
16
GENERATIONS OF PROGRAMMING LANGUAGES

• 1st. Since 1940s. MACHINE LANGUAGE binary code
• 2nd. Since early 50s. ASSEMBLY LANGUAGE
  mnemonics for numeric code
• 3rd. Since mid 50s. HIGH-LEVEL LANGUAGES
• 4th. Since late 50s. MODERN APPLICATION
  PACKAGES

5.16
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HIGH-LEVEL LANGUAGES

• FORTRAN (FORmula TRANslator). Scientific,
  Engineering applications
• COBOL (COmmon Business Oriented Language).
  Predominant for Transaction Processing
• BASIC (Beginners All-purpose Symbolic Instruction
  Code). General Purpose PC Language

5.15
18
HIGH-LEVEL LANGUAGES

• PASCAL. Used to Teach Structured Programming
  Practices. Weak in File Handling, Input / Output
• C and C. Powerful PC Language for Developing
  Applications. Efficient Execution Cross Platform
• PL/1 (Programming Language 1). Powerful IBM
  Language for Business Science
• ADA. Designed for Weapon Systems. Can be used on
  many Platforms. Structured. Can be used for
  Business

5.18
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ARTIFICIAL INTELLIGENCE LANGUAGES

• LISP (LISt Processor). Began late 50s at MIT.
  Preferred in US. Require Specially Configured
  Machines
• PROLOG. Began in early 50s. Preferred outside
  US. Cross Platform
• CREATE MEANINGFUL LISTS OF SYMBOLS (Operations
  Variables Data)

5.19
20
FOURTH GENERATION LANGUAGES (4GL)

• CAN BE EMPLOYED BY END USERS
• NONPROCEDURAL
• CAN DEVELOP APPLICATIONS QUICKLY
• NATURAL LANGUAGES
• SIX CATEGORIES

5.20
21
FOURTH GENERATION LANGUAGES (4GL)

• 1. QUERY LANGUAGES
• rapidly retrieve data
• interactive/ on-line
• may use NATURAL LANGUAGE
• support special requests for data from relational
  databases

5.21
22
FOURTH GENERATION LANGUAGES (4GL)

• 2. REPORT GENERATORS
• create customized reports
• wide range of formats
• 3. GRAPHICS LANGUAGES
• can manipulate drawings, graphs, photos, videos
• presentation managers

5.22
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FOURTH GENERATION LANGUAGES (4GL)

• 4. APPLICATION GENERATORS
• user specifies computer needs
• generator creates logic and code for application
• greatly reduces development time

5.23
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FOURTH GENERATION LANGUAGES (4GL)

• 5. VERY HIGH-LEVEL PROGRAMMING LANGUAGES
• professional programmer productivity tool
• uses fewer instructions
• reduces development time

5.24
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FOURTH GENERATION LANGUAGES (4GL)

• 5. SOFTWARE PACKAGE commercially available set
  of programs...
• WORD PROCESSING
• SPREADSHEETS
• DATA MANAGEMENT
• PRESENTATION MANAGEMENT
• INTEGRATED SOFTWARE PACKAGES NOW COMBINE
  THESE TO SIMPLIFY LEARNING AND USE

5.25
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SOFTWARE TOOLS

• WORD PROCESSING
• SPREADSHEETS
• DATA MANAGEMENT
• PRESENTATION GRAPHICS
• INTEGRATED SOFTWARE SUITES
• E-MAIL
• WEB BROWSERS
• GROUPWARE

5.26
27
GROUPWARE CAPABILITIES

• GROUP WRITING COMMENTING
• ELECTRONIC MAIL DISTRIBUTION
• SCHEDULING MEETINGS, APPOINTMENTS
• SHARED FILES DATABASES
• SHARED TIMELINES, PLANS
• ELECTRONIC MEETINGS CONFERENCES

5.25
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OBJECT-ORIENTED PROGRAMMING

• COMBINES DATA PROCEDURES INTO A SINGLE OBJECT
• PROGRAM SENDS MESSAGE TO OBJECT TO PERFORM
  EMBEDDED PROCEDURE
• OBJECTS DATA ENCAPSULATED FROM REST OF SYSTEM
• CREATES REUSABLE CODE
• REDUCES TIME AND COST OF WRITING SOFTWARE

5.28
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OBJECT-ORIENTED PROGRAMMING

• VISUAL PROGRAMMING SELECT AND ARRANGE OBJECTS
  RATHER THAN WRITE CODE
• CLASS ALL OBJECTS OF A CLASS HAVE ALL FEATURES
  OF THAT CLASS
• INHERITANCE SPECIFIC CLASS RECEIVES FEATURES OF
  A MORE GENERAL CLASS
• OVERRIDE SUBCLASS MAY OVEERRIDE INHERITED METHOD
  (e.g. Printout of an HOURLY worker Pay Check may
  differ from that of a WEEKLY worker

5.29
30
OBJECT-ORIENTED PROGRAMMING

• JAVA Sun Microsystems OBJECT-ORIENTED
  PROGRAMMING LANGUAGE
• APPLET TINY PROGRAM TO EXECUTE SMALL FUNCTION
• APPLETS DOWNLOADED FROM NETWORK
• RUN ON ANY COMPUTER OPERATING SYSTEM
• RESULT SAVED ON NETWORK, NOT ON PC
• ONLY NETWORK VERSION OF SOFTWARE NEEDS UPGRADE

5.30
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OBJECT-ORIENTED PROGRAMMING

• ActiveX CONTROLS FOR WINDOWS SOFTWARE
  ENVIRONMENT to enable OBJECTS e.g.,
• CHARTS
• TABLES
• ANIMATIONS
• to be EMBEDDED IN A WEB PAGE

5.31
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5.32
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7. INFORMATION SYSTEMS SOFTWARE
5.33