1. L Ch5: Software Review Learning Objectives
DESCRIBE MAJOR TYPES OF SOFTWARE
EXAMINE SYSTEM SOFTWARE & OPERATING SYSTEMS
EXPLAIN SOFTWARE EVOLUTION
ANALYZE MAJOR APPLICATION LANGUAGES
DESCRIBE APPROACHES TO SOFTWARE DEVELOPMENT
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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
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3. SOFTWARE OPERATING SYSTEM:
APPLICATION SOFTWARE
OPERATING SYSTEM:
SCHEDULED COMPUTER EVENTS ALLOCATES COMPUTER RESOURCES MONITORS EVENTS
LANGUAGE TRANSLATORS:
INTERPRETERS COMPILERS
UTILITY PROGRAMS:
ROUTINE OPERATIONS MANAGE DATA
SYSTEM SOFTWARE
HARDWARE
PROGRAMMING LANGUAGES:
ASSEMBLY LANGUAGE; FORTRAN; COBOL; PL / 1; QBASIC; PASCAL; C; C++; “FOURTH GENERATION” LANGUAGES
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4. Software Classification (Alternative view)
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5. OPERATING SYSTEM MANAGES & CONTROLS ACTIVITIES ALLOCATION & ASSIGNMENT
SCHEDULING
MONITORING
SYSTEM RESIDENCE DEVICE:
SECONDARY STORAGE DEVICE STORING OPERATING SYSTEM
Common OS’
DOS; Windows 95 & 98; Windows NT; Windows CE; OS/2; UNIX; Mac OS
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6. TRADITIONAL SINGLE-PROGRAM SYSTEM MULTIPROGRAMMING ENVIRONMENT
OPERATING SYSTEM
UNUSED MEMORY
OPERATING SYSTEM
UNUSED MEMORY
PROGRAM 1
PROGRAM 2
PROGRAM 3
PROGRAM 1
MULTITASKING
MULTIPROGRAMMING ON A SINGLE-USER SYSTEM
SUCH AS A MICROCOMPUTER
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7. Virtual Storage & Time Sharing
STORED PROGRAM CONCEPT
A program can not be executed unless it is stored in primary memory w/ data.
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
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
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8. MULTIPROCESSING TWO OR MORE PARALLEL PROCESSORS IN SYSTEM
PROGRAM CAN BE DIVIDED TO BE PROCESSED BY MULTIPLE CPUs
CAN PROCESS LARGE PROGRAMS MORE RAPIDLY
Is it really paralleling at the lowest CPU level ?
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9. OTHER OBJECT CODE MODULES
LANGUAGE TRANSLATION
SOURCE CODE PROGRAM
SOURCE CODE:
HIGH-LEVEL LANGUAGE INSTRUCTIONS
COMPILER:
TRANSLATES HIGH-LEVEL CODE INTO MACHINE LANGUAGE
OBJECT CODE:
TRANSLATED INSTRUCTIONS READY FOR COMPUTER
COMPILER
TRANSLATION PROCESS
OBJECT CODE
OTHER OBJECT CODE MODULES
LINKAGE EDITOR
LOAD MODULE
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10. GRAPHICAL USER INTERFACE (GUI)
OPERATING SYSTEM USES:
GRAPHIC ICONS (Icons, Buttons, Bars, Boxes)
MOUSE
TO ISSUE COMMANDS
MAKE SELECTIONS
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11. 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
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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
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
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13. 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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14. FOURTH GENERATION LANGUAGES (4GL)
CAN BE EMPLOYED BY END USERS
NONPROCEDURAL
CAN DEVELOP APPLICATIONS QUICKLY
NATURAL LANGUAGES
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15. FOURTH GENERATION LANGUAGES (4GL)
SIX CATEGORIES
1. Query languages:
rapidly retrieve data; interactive/ on-line; may use NATURAL LANGUAGE; support special requests for data from relational databases
2. Report Generators:
create customized reports; wide range of formats
3. Graphics Generators
can manipulate drawings, graphs, photos, videos; presentation managers
4. Application Generators:
user specifies computer needs; generator creates logic and code for application; greatly reduces development time
5. Very High Level Prog. Languages:
professional programmer productivity tool; uses fewer instructions; reduces development time
6. Software Packages/PC Software tools
Commercially available set of programs…(eg. MS office / Lotus Suite)
Integrated suites/ /Web Browser/Groupware
6.25
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16. OBJECT-ORIENTED PROGRAMMING
COMBINES DATA & PROCEDURES INTO A SINGLE OBJECT.
Class:
ALL OBJECTS OF A CLASS HAVE ALL FEATURES OF THAT CLASS
Message:
PROGRAM SENDS MESSAGE TO OBJECT TO PERFORM EMBEDDED PROCEDURE
Encapsulation:
OBJECT’S DATA ENCAPSULATED FROM REST OF SYSTEM
Inheritance:
SPECIFIC CLASS RECEIVES FEATURES OF A MORE GENERAL CLASS
Overriding:
SUBCLASS MAY OVEERRIDE INHERITED METHOD
Visual Programming: (Not all OOP)
SELECT AND ARRANGE OBJECTS RATHER THAN WRITE Code
REDUCES TIME AND COST OF WRITING SOFTWARE
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17. 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
ActiveX: CONTROLS FOR WINDOWS SOFTWARE ENVIRONMENT
to enable OBJECTS: e.g., CHARTS, TABLES, ANIMATIONS to be EMBEDDED IN A WEB PAGE
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