7.1
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
*
7.2
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
*
7.3
SOFTWARE
APPLICATION SOFTWARE
SYSTEM SOFTWARE
HARDWARE
OPERATING SYSTEM:
SCHEDULED COMPUTER
EVENTS
ALLOCATES
COMPUTER RESOURCES
MONITORS EVENTS
LANGUAGE TRANSLATORS:
INTERPRETERS
COMPILERS
UTILITY PROGRAMS:
PROGRAMMING LANGUAGES:
ROUTINE OPERATIONS
MANAGE DATA
ASSEMBLY LANGUAGE; FORTRAN;
COBOL; PL / 1; QBASIC; PASCAL; C; C++;
“FOURTH GENERATION” LANGUAGES
7.4
OPERATING SYSTEM
MANAGES & CONTROLS ACTIVITIES
• ALLOCATION & ASSIGNMENT
• SCHEDULING
• MONITORING
• SYSTEM RESIDENCE DEVICE:
SECONDARY STORAGE DEVICE
STORING OPERATING SYSTEM
*
7.5
MULTIPROGRAMMING
7.6
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
ENVIRONMENT
OPERATING SYSTEM
OPERATING SYSTEM
TRADITIONAL SINGLEPROGRAM SYSTEM
PROGRAM 1
PROGRAM 2
PROGRAM 3
UNUSED MEMORY
MULTITASKING
MULTIPROGRAMMING
ON A
SINGLE-USER SYSTEM
SUCH AS A
MICROCOMPUTER
*
7.7
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
*
7.8
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
• USER’S JOB SWAPPED OUT AT END
OF SLICE
7.9
*
MULTIPROCESSING
• TWO OR MORE PARALLEL
PROCESSORS IN SYSTEM
• PROGRAM CAN BE DIVIDED TO BE
PROCESSED BY MULTIPLE CPUs
• CAN PROCESS LARGE PROGRAMS
MORE RAPIDLY
*
7.10
LANGUAGE
TRANSLATION
• SOURCE CODE: HIGH-LEVEL
LANGUAGE INSTRUCTIONS
• COMPILER: TRANSLATES HIGHLEVEL CODE INTO MACHINE
LANGUAGE
• OBJECT CODE: TRANSLATED
INSTRUCTIONS READY FOR
COMPUTER
*
7.11
COMPILER
OBJECT CODE
LINKAGE
EDITOR
LOAD MODULE
7.12
OTHER OBJECT
CODE MODULES
TRANSLATION PROCESS
SOURCE CODE
PROGRAM
GRAPHICAL USER INTERFACE
(GUI)
OPERATING SYSTEM USES:
• GRAPHIC ICONS (Icons, Buttons,
Bars, Boxes)
• MOUSE
• TO ISSUE COMMANDS
• MAKE SELECTIONS
*
7.13
MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
Windows 98 & 95
FEATURES
32-bit operating system; GUI; Multitasking.
Networking
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
OS/2
32-bit. Developed for IBM PS/2. Multitasking;
Networking
7.14
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
DOS
7.15
For IBM (PC-DOS) and PC (MS-DOS).
Program Memory: 640K
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 ‘70s. MODERN
APPLICATION PACKAGES
7.16
*
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
*
7.17
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
*
7.18
ARTIFICIAL INTELLIGENCE
LANGUAGES
• LISP (LISt Processor). Began late
‘50s at MIT. Preferred in US. Require
Specially Configured Machines
• PROLOG. Began in early ‘70s.
Preferred outside US. Cross Platform
CREATE MEANINGFUL LISTS OF
SYMBOLS (Operations; Variables;
Data)
*
7.19
FOURTH GENERATION
LANGUAGES (4GL)
• CAN BE EMPLOYED BY END USERS
• NONPROCEDURAL
• CAN DEVELOP APPLICATIONS
QUICKLY
• NATURAL LANGUAGES
• SIX CATEGORIES
*
7.20
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
*
7.21
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
*
7.22
FOURTH GENERATION
LANGUAGES (4GL)
4. APPLICATION GENERATORS:
• user specifies computer needs
• generator creates logic and code for
application
• greatly reduces development time
*
7.23
FOURTH GENERATION
LANGUAGES (4GL)
5. VERY HIGH-LEVEL PROGRAMMING
LANGUAGES:
• professional programmer productivity tool
• uses fewer instructions
• reduces development time
*
7.24
FOURTH GENERATION
LANGUAGES (4GL)
7. 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
7.25
*
SOFTWARE TOOLS
•
•
•
•
•
•
•
•
WORD PROCESSING
SPREADSHEETS
DATA MANAGEMENT
PRESENTATION GRAPHICS
INTEGRATED SOFTWARE SUITES
E-MAIL
WEB BROWSERS
GROUPWARE
*
7.26
GROUPWARE CAPABILITIES
• GROUP WRITING & COMMENTING
• ELECTRONIC MAIL DISTRIBUTION
• SCHEDULING MEETINGS,
APPOINTMENTS
• SHARED FILES & DATABASES
• SHARED TIMELINES, PLANS
• ELECTRONIC MEETINGS &
CONFERENCES
7.27
*
OBJECT-ORIENTED
PROGRAMMING
• COMBINES DATA & PROCEDURES INTO A
SINGLE OBJECT
• PROGRAM SENDS MESSAGE TO OBJECT
TO PERFORM EMBEDDED PROCEDURE
• OBJECT’S DATA ENCAPSULATED FROM
REST OF SYSTEM
• CREATES REUSABLE CODE
• REDUCES TIME AND COST OF WRITING
SOFTWARE
7.28
*
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
7.29
*
OBJECT-ORIENTED
PROGRAMMING
JAVA: Sun Microsystems OBJECT-ORIENTED
•
•
•
•
•
7.30
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
*
OBJECT-ORIENTED
PROGRAMMING
ActiveX: CONTROLS FOR WINDOWS
SOFTWARE ENVIRONMENT to enable
•
•
•
•
7.31
OBJECTS: e.g.,
CHARTS
TABLES
ANIMATIONS
to be EMBEDDED IN A WEB PAGE
*
Connect to the INTERNET
PRESS LEFT MOUSE BUTTON ON ICON TO
CONNECT TO THE LAUDON & LAUDON
WEB SITE FOR MORE INFORMATION ON
THIS CHAPTER
7.32
7.33