1 chapter 5 information systems in business software
TRANSCRIPT
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Chapter 5Information
Systemsin Business
Software
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Software: Instructions to the Computer
A computer program is a series of instructions to a computer to execute any and all processes.
Computers only “understand” instructions consisting of electrical signals alternating between two states.
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Programming Languages
Programming languages
Abbreviated forms of instructions that translate into machine language
New programming languages make programming easier for people who are not necessarily hardware experts
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Machine Languages (ML)
Only languages computers can directly interpret to carry out instructions
ML coding: time-consuming and error-prone
ML programmers: concerned with hardware details
Every computer or family of computers has its own ML; each is machine-dependent.
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More English-like; codes shorter than machine languages
Assembler translates into machine language
Advantages of machine or assembly languagesProgrammer in control of hardwarePrograms written in low-level languages
run more efficiently.
Assembly Languages
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Procedural Languages
Third-generation (procedural) languages are more English-like than assembly languages.
Relatively easy to learn, write, and debug.
FORTRAN, COBOL, BASIC
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4GLs are more English-like than procedural languages.
Easy to learn and use; shorter application development time.
PowerBuilder, FOCUS, NOMAD, and RAMIS
Fourth Generation Languages (4GL)
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Levels of programming Language:
9-179-17
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Languages that let programmers create field windows, scroll-down menus, click buttons, etc., by choosing from a palette
Appropriate code written automatically
Accelerates work
Microsoft’s Visual Basic
Visual Programming
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Emphasis on the objects involved in the task, not on the procedure
An object encapsulates a data set with the code that is used to operate on it
Standardized programming modules can be reused
Object-Oriented Programming (OOP)
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Advantages of Object-Oriented Programming
over Procedural Languages
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Advantages and disadvantages
of higher-level programming languages
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Application: a program developed to address a specific business need; software for development of such programs.
System: programs designed to carry out general routine operations, such as loading, copying, or deleting a file.
Application Software vs.
System Software
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Application Software
Custom-Designed Applications Advantages:
Meeting the organization’s needs exactly
In-house developers are sensitive to the organizational culture
Disadvantages:High costProduction schedule subject to long
delays Incompatible with other
organizations’ systems
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Advantages and disadvantages of tailored applications
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Advantages:Low costHigh qualityVendor support Immediate availability
Often tested at user sites (alpha sites and beta sites) before the final version is released
Packaged Software
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Advantages and disadvantages
of packaged software
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System SoftwareManages computer resources and performs routine tasks not specific to any application Copying and pasting sections and files Printing documents Allocating memory
Developed to partner with application software
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Most important system software
Developed for a certain microprocessor or microprocessors
Plays the role of “traffic cop” or the “boss” of computer resources
Operating Systems (O/S)
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The operating system mediates between applications and the computer, and controls peripheral devices.
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Systems Management
User Interface
Memory Allocation
Multitasking, Multiprogramming, and Multiprocessing
Times and Statistics
Increasing Services from O/Ss
Operating System Functions
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MICROCOMPUTER OPERATING SYSTEMSMICROCOMPUTER OPERATING SYSTEMS
32-bit operating system; GUI; Multitasking. 32-bit operating system; GUI; Multitasking. NetworkingNetworking
32-bit operating system not limited to Intel chips. 32-bit operating system not limited to Intel chips. Multitasking; Multiprocessing; NetworkingMultitasking; Multiprocessing; Networking
32-bit. Developed for IBM PS/2. Multitasking; 32-bit. Developed for IBM PS/2. Multitasking; NetworkingNetworking
Paired-down for handheld computers, wireless Paired-down for handheld computers, wireless communication devicescommunication devices
Windows 98 & Windows 98 & 9595
Windows NT Windows NT Me, Me,
2000&XP2000&XP
Windows CEWindows CE
OS/2OS/2
OPERATING SYSTEMOPERATING SYSTEM FEATURESFEATURES
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OPERATING SYSTEMOPERATING SYSTEM
MICROCOMPUTER OPERATING SYSTEMSMICROCOMPUTER OPERATING SYSTEMS
Mac OSMac OS For Macintosh computers. Multitasking. For Macintosh computers. Multitasking. Powerful Graphics; MultimediaPowerful Graphics; Multimedia
UnixUnix For powerful Microcomputers, Workstations, For powerful Microcomputers, Workstations, Minicomputers. Multitasking; Multi-user Minicomputers. Multitasking; Multi-user Processing; Networking. Portable to various Processing; Networking. Portable to various Computer PlatformsComputer Platforms
DOSDOS For IBM (PC-DOS) and PC (MS-DOS). For IBM (PC-DOS) and PC (MS-DOS). Program Memory: 640KProgram Memory: 640K
LinuxLinux Free, reliable alternative to Unix, Windows. Free, reliable alternative to Unix, Windows. Runs on many PlatformsRuns on many Platforms
FEATURESFEATURES
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Popular Operating System
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Compiler Scans source code and translates into
object code Generates error message and does not
compile when an error is found Allows users to save programs in object
code
Interpreter Checks one statement at a time Changes error-free statements into ML Generates an error message for errors
Compilers and Interpreters
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Controls and supports data communication activities in a network
Setting up rules that govern transmission and reception of data
Connecting and disconnecting communication links
Assigning priorities among terminals in a network
Detecting and correcting transmission errors
Data Communication Programs
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Proprietary O/S: limited to using applications compatible with it
Open O/S: compatible with virtually all applications.
Completely open O/S does not exist
Some O/Ss (e.g., Unix) are said to be nonproprietary, but it is still impossible to run many applications on different versions of such O/Ss.
Proprietary vs. Open Source
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Sample results of software evaluation
(5 is the highest score.)