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Chapter 5 Information Systems in Business: Software Chapter 5 Information Systems in Business: Software

Learning Objectives When you finish this chapter, you will: n n n Understand why Learning Objectives When you finish this chapter, you will: n n n Understand why managers must keep abreast of software developments. Recognize the different generations of programming languages and how they differ. Understand the difference between application software and system software. 2

Learning Objectives n n n Know the strengths and weaknesses of tailored software vs. Learning Objectives n n n Know the strengths and weaknesses of tailored software vs. off-the-shelf software. Be able to cite the latest major developments in application and system software. Recognize characteristics that are important in evaluating packaged software application for business use. 3

Software: Instructions to the Computer A computer program is a series of instructions to 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. 4

Programming Languages Programming languages n n Abbreviated forms of instructions that translate into machine Programming Languages Programming languages n n Abbreviated forms of instructions that translate into machine language New programming languages make programming easier for people who are not necessarily hardware experts 5

Programming Languages Figure 5. 1 The evolution of programming languages 6 Programming Languages Figure 5. 1 The evolution of programming languages 6

Programming Languages Machine Languages (ML) n n Only languages computers can directly interpret to Programming Languages Machine Languages (ML) n n 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. 7

Programming Languages Machine Languages (ML) 01011010 00010000 11110011 10110010 Binary Operation Code Binary Operand Programming Languages Machine Languages (ML) 01011010 00010000 11110011 10110010 Binary Operation Code Binary Operand 8

Programming Languages Assembly Languages n n Represents a string of ‘ 0 s’ and Programming Languages Assembly Languages n n Represents a string of ‘ 0 s’ and ‘ 1 s’ for a machine language instruction More English-like; codes shorter than machine languages n Assembler translates into machine language n Advantages of machine or assembly languages w Programmer in control of hardware w Programs written in low-level languages run more efficiently. 9

Programming Languages Assembly Languages ADD Symbolic Operation Code X Symbolic Operand 10 Programming Languages Assembly Languages ADD Symbolic Operation Code X Symbolic Operand 10

Programming Languages Procedural Languages n n Third-generation (procedural) languages are more English-like than assembly Programming Languages Procedural Languages n n Third-generation (procedural) languages are more English-like than assembly languages. Programmers focus on the procedure of the application problem at hand. n Some languages are standardized or portable. n Relatively easy to learn, write, and debug. n FORTRAN, COBOL, BASIC 11

Programming Languages Procedural Languages FORTRAN: Formular Translation (1950) COBOL: Common Business Oriented language (1959) Programming Languages Procedural Languages FORTRAN: Formular Translation (1950) COBOL: Common Business Oriented language (1959) BASIC: Beginner’s All-Purpose Symbolic Instruction (1960) C : (1970) -> 具第二代語言的功能 12

Programming Languages Fourth Generation Languages (4 GL) n n 4 GLs are more English-like Programming Languages Fourth Generation Languages (4 GL) n n 4 GLs are more English-like than procedural languages. Programmer only has to select an action without having to specify the action’s formula or procedure. Easy to learn and use; shorter application development time. Power. Builder, FOCUS, NOMAD, and RAMIS 13

Programming Languages Fourth Generation Languages (4 GL) Query Language: SQL Report Generator Forms Designer Programming Languages Fourth Generation Languages (4 GL) Query Language: SQL Report Generator Forms Designer SELECT ADDRESS FROM PERSONNEL WHERE NAME=“JONES” Application Generator 14

Programming Languages Figure 5. 2 The instruction “ADD 2 and 5 and assign the Programming Languages Figure 5. 2 The instruction “ADD 2 and 5 and assign the result to variable y” written in different programming languages 15

Programming Languages Visual Programming n Languages that let programmers create field windows, scroll-down menus, Programming Languages Visual Programming n Languages that let programmers create field windows, scroll-down menus, click buttons, etc. , by choosing from a palette n Appropriate code written automatically n Accelerates work n Microsoft’s Visual Basic 16

Programming Languages Object-Oriented Programming (OOP) n n Emphasis on the objects involved in the Programming Languages Object-Oriented Programming (OOP) n n 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. Applications can be rapidly developed with appropriate objects from an object library. 17

Programming Languages Figure 5. 3 Advantages of object-oriented programming (OOP) over procedural languages 18 Programming Languages Figure 5. 3 Advantages of object-oriented programming (OOP) over procedural languages 18

Programming Languages Figure 5. 4 The object EMPLOYEE 19 Programming Languages Figure 5. 4 The object EMPLOYEE 19

Programming Languages Figure 5. 5 Advantages and disadvantages of higher-level programming languages 20 Programming Languages Figure 5. 5 Advantages and disadvantages of higher-level programming languages 20

Programming Languages n Application Software vs. System Software w Application: a program developed to Programming Languages n Application Software vs. System Software w Application: a program developed to address a specific business need; software for development of such programs. w System: programs designed to carry out general routine operations, such as loading, copying, or deleting a file. 21

Application Software Application-specific programs n Programs designed to perform specific jobs General-purpose programs n Application Software Application-specific programs n Programs designed to perform specific jobs General-purpose programs n Usable for different purposes 22

Application Software Custom-Designed Applications n Advantages: w Meeting the organization’s needs exactly w In-house Application Software Custom-Designed Applications n Advantages: w Meeting the organization’s needs exactly w In-house developers are sensitive to the organizational culture n Disadvantages: w High cost w Production schedule subject to long delays w Incompatible with other organizations’ systems 23

Application Software Figure 5. 6 Advantages and disadvantages of tailored applications 24 Application Software Figure 5. 6 Advantages and disadvantages of tailored applications 24

Application Software Packaged Software n Advantages: w Low cost w High quality w Vendor Application Software Packaged Software n Advantages: w Low cost w High quality w Vendor support w Immediate availability n Often tested at user sites (alpha sites and beta sites) before the final version is released. 25

Application Software Figure 5. 7 Advantages and disadvantages of packaged software 26 Application Software Figure 5. 7 Advantages and disadvantages of packaged software 26

Applications Software Packaged Software n Word processors n Electronic spreadsheets n Database management systems Applications Software Packaged Software n Word processors n Electronic spreadsheets n Database management systems 27

Packaged Software Figure 5. 8 Electronic spreadsheets are powerful tools for (a) tabulation, (b) Packaged Software Figure 5. 8 Electronic spreadsheets are powerful tools for (a) tabulation, (b) manipulation, and (c) data analysis. 28

Packaged Software Multimedia n n n Can handle many different types of data such Packaged Software Multimedia n n n Can handle many different types of data such as text, voice, and image. Powerful means of communicating. Uses include education, training, research, and business. 29

Packaged Software Virtual Reality (VR) n n n Mimics sensory reality. Some sophisticated VR Packaged Software Virtual Reality (VR) n n n Mimics sensory reality. Some sophisticated VR software includes use of goggles, gloves, earphones, and a moving base. Business use of VR is expected to grow dramatically for design and testing of new products, and for marketing. 30

System Software Manages computer resources and performs routine tasks not specific to any application System Software Manages computer resources and performs routine tasks not specific to any application n Copying and pasting sections and files n Printing documents n Allocating memory Developed to partner with application software 31

System Software Operating Systems (O/S) n Most important system software w Developed for a System Software Operating Systems (O/S) n Most important system software w Developed for a certain microprocessor or microprocessors w Addresses technical details such as registers and RAM addresses. w Plays the role of “traffic cop” or the “boss” of computer resources. 32

System Software Figure 5. 9 The operating system mediates between applications and the computer, System Software Figure 5. 9 The operating system mediates between applications and the computer, and controls peripheral devices. 33

System Software Figure 5. 10 Computers operate on a number of layers, starting from System Software Figure 5. 10 Computers operate on a number of layers, starting from the user interface and moving inward to the hardware. 34

System Software Figure 5. 11 Popular operating systems 35 System Software Figure 5. 11 Popular operating systems 35

System Software n Operating System Functions w Systems Management w User Interface w Memory System Software n Operating System Functions w Systems Management w User Interface w Memory Allocation w Multitasking, Multiprogramming, and Multiprocessing w Times and Statistics w Increasing Services from O/Ss 36

System Software Compilers and Interpreters n Compiler w Scans source code and translates into System Software Compilers and Interpreters n Compiler w Scans source code and translates into object code w Generates error message and does not compile when an error is found w Allows users to save programs in object code n Interpreter w Checks one statement at a time w Changes error-free statements into ML w Generates an error message for errors 37

System Software Figure 5. 12 A compiler converts higher-level language code (source code) into System Software Figure 5. 12 A compiler converts higher-level language code (source code) into machine language (object code), which the computer can process. 38

System Software Data Communication Programs n Controls and supports data communication activities in a System Software Data Communication Programs n Controls and supports data communication activities in a network w Setting up rules that govern transmission and reception of data w Connecting and disconnecting communication links w Assigning priorities among terminals in a network w Detecting and correcting transmission errors 39

System Software Proprietary vs. Open Source From Computers to Appliances 40 System Software Proprietary vs. Open Source From Computers to Appliances 40

Considerations in Purchasing Software Figure 5. 13 Sample software evaluation form 41 Considerations in Purchasing Software Figure 5. 13 Sample software evaluation form 41

Considerations in Purchasing Software Figure 5. 14 Sample results of software evaluation (5 is Considerations in Purchasing Software Figure 5. 14 Sample results of software evaluation (5 is the highest score. ) 42

The Year 2000 Problem Many business applications stored only the last two digits of The Year 2000 Problem Many business applications stored only the last two digits of year dates. If no corrective action taken, businesses might have experienced chaos on January 1, 2000. n ISs interpreting 00 as 1900 instead of 2000 Experts predict the Y 2 K bug will haunt many organizations several years after 2000. 43