Transcript CHAP7 - Lyle School of Engineering

7.1
INFORMATION SYSTEM
BUSINESS
CHALLENGE
MANAGEMENT
INFORMATION
INFORMATION
BUSINESS
SYSTEM
SOLUTIONS
TECHNOLOGY
INCREASING COMPLEXITY AND
SOFTWARE ERRORS
ORGANIZATION
7.2
APPLICATION BACKLOG
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
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7.3
SOFTWARE
APPLICATION SOFTWARE
SYSTEM SOFTWARE
HARDWARE
OPERATING SYSTEM:
SCHEDULED COMPUTER
EVENTS
ALLOCATES
COMPUTER RESOURCES
MONITORS EVENTS
LANGUAGE TRANSLATORS:
INTERPRETERS
COMPILERS
UTILITY PROGRAMS:
ROUTINE OPERATIONS
MANAGE DATA
7.4
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
7.5
OPERATING SYSTEM
MANAGES & CONTROLS ACTIVITIES
• ALLOCATION & ASSIGNMENT
• SCHEDULING
• MONITORING
• SYSTEM RESIDENCE DEVICE:
SECONDARY STORAGE DEVICE
STORING OPERATING SYSTEM
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7.6
MULTIPROGRAMMING
OPERATING SYSTEM
TRADITIONAL SINGLEPROGRAM SYSTEM
7.7
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
7.8
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
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7.9
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
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7.10
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
7.11
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MULTIPROCESSING
• TWO OR MORE PARALLEL
PROCESSORS IN SYSTEM
• PROGRAM CAN BE DIVIDED TO BE
PROCESSED BY MULTIPLE CPUs
• CAN PROCESS LARGE PROGRAMS
MORE RAPIDLY
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7.12
LANGUAGE TRANSLATION
• SOURCE CODE: HIGH-LEVEL
LANGUAGE INSTRUCTIONS
• COMPILER: TRANSLATES HIGHLEVEL CODE INTO MACHINE
LANGUAGE
• OBJECT CODE: TRANSLATED
INSTRUCTIONS READY FOR
COMPUTER
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7.13
COMPILER
OBJECT CODE
LINKAGE
EDITOR
LOAD MODULE
7.14
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
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7.15
MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
FEATURES
DOS
For IBM (PC-DOS) and PC (MS-DOS). Program Memory: 640K
Windows 95
32-bit operating system; GUI; Multitasking. Networking
Windows NT
32-bit; microcomputers & workstations. Not limited to Intel
chips. Multitasking; Multiprocessing; Networking
OS/2
32-bit. Developed for IBM PS/2. Multitasking; Networking
UNIX; XENIX
For powerful Microcomputers, Workstations, Minicomputers.
Multitasking; Multi-user Processing; Networking. Portable to
various Computer Platforms
System 7
For Macintosh computers. Multitasking. Powerful Graphics;
Multimedia
7.16
7.17
GENERATIONS OF PROGRAMMING
LANGUAGES
7.18
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
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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
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7.19
HIGH-LEVEL LANGUAGES
• PL/1 (Programming Language 1). Powerful
IBM Language for Business & Science
• PASCAL. Used to Teach Structured
Programming Practices. Weak in File
Handling, Input / Output
• ADA. Designed for Weapon Systems. Can
be used on many Platforms. Structured.
Can be used for Business
• C. Powerful PC Language for Developing
Applications. Efficient Execution; Cross
Platform
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7.20
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)
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7.21
7.22
FOURTH GENERATION LANGUAGES
(4GL)
• CAN BE EMPLOYED BY END USERS
• NONPROCEDURAL
• CAN DEVELOP APPLICATIONS
QUICKLY
• NATURAL LANGUAGES
• SIX CATEGORIES
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723
FOURTH GENERATION LANGUAGES
(4GL)
1. QUERY LANGUAGES:
• RAPIDLY RETRIEVE DATA
• INTERACTIVE
• ON-LINE
• SUPPORT SPECIAL REQUESTS FOR
DATA FROM RELATIONAL
DATABASES
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7.24
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
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7.25
FOURTH GENERATION LANGUAGES
(4GL)
4. APPLICATION GENERATORS:
• USER SPECIFIES COMPUTER NEEDS
• GENERATOR CREATES LOGIC AND CODE
FOR APPLICATION
• GREATLY REDUCES DEVELOPMENT TIME
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7.26
FOURTH GENERATION LANGUAGES
(4GL)
5. VERY HIGH-LEVEL PROGRAMMING
LANGUAGES:
• PROFESSIONAL PROGRAMMER
PRODUCTIVITY TOOL
• USES FEWER INSTRUCTIONS
• REDUCES DEVELOPMENT TIME
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7.27
FOURTH GENERATION LANGUAGES
(4GL)
6. 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
7.28
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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
7.29
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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
7.30
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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
7.31
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7.32