Transcript 7. information systems software

SOFTWARE
5.1
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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System SW, Application development SW, Applications
Computer Software
Computer
Software
Application
Software
General purpose
Application
Programs
•Web browsers
•E-mail
•Word processing
•Spreadsheets
•Presentation graphics
•Groupware
5.2
Performs information
Processing tasks for
End users
Application –
Specific
Programs
•ERP
•Business Apps
•E-Commerce
•Education
•Entertainment
System
Software
System
Management
Programs
•Operating systems
•Network management
•System utilities
•Performance monitors
•Security monitors
Manages and supports
Operations of computer
Systems and networks
System
Development
Programs
•Programming languages
•Application development
SOFTWARE
APPLICATION SOFTWARE
SYSTEM SOFTWARE
HARDWARE
Simultaneous
Activities
OPERATING SYSTEM: Priorities
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
5.3
MULTIPROGRAMMING
5.4
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
ENVIRONMENT
OPERATING SYSTEM
OPERATING SYSTEM
TRADITIONAL SINGLEPROGRAM SYSTEM
PROGRAM 1
PROGRAM 2
PROGRAM 3
UNUSED MEMORY
Concurrent use of CPU / execute until I/O rqst
MULTITASKING
MULTIPROGRAMMING
ON A
SINGLE-USER SYSTEM
SUCH AS A
MICROCOMPUTER
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One person can run two or more programs or tasks
Concurrently. Multiple windows open.
Could not do this under DOS
5.5
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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5.6
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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5.7
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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5.8
COMPILER
OBJECT CODE
LINKAGE
EDITOR
LOAD MODULE
5.9
OTHER OBJECT
CODE MODULES
TRANSLATION PROCESS
SOURCE CODE
PROGRAM
MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
Windows 98 & 95
FEATURES
32-bit operating system; GUI; Multitasking.
Networking
Windows NT
Me & 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
List example operating systems
5.10
MICROCOMPUTER OPERATING SYSTEMS
OPERATING SYSTEM
Unix
5.11
FEATURES
For powerful Microcomputers, Workstations,
Minicomputers. Multitasking; Multi-user
Processing; Networking. Portable to various
Computer Platforms
Linux
Free, reliable alternative to Unix, Windows.
Runs on many Platforms
Mac OS
For Macintosh computers. Multitasking.
Powerful Graphics; Multimedia
DOS
For IBM (PC-DOS) and PC (MS-DOS).
Program Memory: 640K
GENERATIONS OF
PROGRAMMING LANGUAGES
1st. MACHINE LANGUAGE: binary code
0’s and 1’s
2nd. ASSEMBLY LANGUAGE: mnemonics
Registers
for
numeric code
3rd. HIGH-LEVEL LANGUAGES – written
with regular words (fortran, cobol)
4th. MODERN APPLICATION PACKAGES
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5.12
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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5.13
FOURTH GENERATION
LANGUAGES (4GL)
• CAN BE EMPLOYED BY END USERS
• NONPROCEDURAL
• CAN DEVELOP APPLICATIONS
QUICKLY
• NATURAL LANGUAGES
• SIX CATEGORIES
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5.14
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
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5.15
FOURTH GENERATION
LANGUAGES (4GL)
5.16
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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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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5.17
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
5.18
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New Development Tools
Platform independent
JAVA: Sun Microsystems OBJECT-ORIENTED
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PROGRAMMING LANGUAGE (all appliances)
APPLET: TINY PROGRAM TO EXECUTE SMALL
FUNCTION (Runs in browser)
APPLETS DOWNLOADED FROM NETWORK
RUN ON ANY COMPUTER & OPERATING
SYSTEM (in theory … bull)
Requires JVM – part of web browser. Interprets
each command. (runs in a “sandbox”
Servlet – Java program runs on server
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5.19
New Development Tools
HTML – used to display a Web page and tells where words should be
Placed. (Hypertext markup language)
Interpreted by web browsers (IE and Netscape)
XML – eXtensible Markup Language – describes the data
DTD – document type definition
5.20
ASP – Application Service Providers
Host application SW for other businesses,
usually over the Web.
ExpensAble.com – (T&E) travel and enter.
expense reporting SW via web. $5K one time
fee and $5/user/month.
Advantages:
No need to maintain SW or HW
Always available
Auto updates
Browser is only SW required
5.21