Chapter 5 Information Systems in Business: Software

Chapter 5 Information Systems in Business: Software

Learning Objectives When you finish this chapter, you will: – 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 – 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 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 – 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 Machine Languages (ML) – Only languages computers can directly interpret to carry out instructions – String of ‘0s’ and ‘1s’ for a machine language instruction – 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 Assembly Languages – More English-like; codes shorter than machine languages – Assembler translates into machine language – Advantages of machine or assembly languages Programmer in control of hardware Programs written in low-level languages run more efficiently. 8

Programming Languages Figure 5.2 The instruction “ADD 2 and 5 and assign the result to variable y” written in different programming languages 9

Programming Languages Procedural Languages – Third-generation (procedural) languages are more English-like than assembly languages. – Programmers focus on the procedure of the application problem at hand. – Some languages are standardized or portable. – Relatively easy to learn, write, and debug. – FORTRAN, COBOL, BASIC – Requires compiling and linking to test 10

Programming Languages Fourth Generation Languages (4GL) – 4GLs 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. – PowerBuilder, FOCUS, NOMAD, and RAMIS 11

Programming Languages Visual Programming – Languages that let programmers create field windows, scroll-down menus, click buttons, etc., by choosing from a palette – Appropriate code written automatically – Integrated programming environment – Accelerates work – Microsoft’s Visual Basic 12

Programming Languages Object-Oriented Programming (OOP) – 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. 13

Programming Languages Figure 5.3 Advantages of object-oriented programming (OOP) over procedural languages 14

Programming Languages Figure 5.4 The object EMPLOYEE 15

Programming Languages Figure 5.5 Advantages and disadvantages of higher-level programming languages 16

Programming Languages Application Software vs. System Software 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. 17

Application Software Application-specific programs – Programs designed to perform specific jobs General-purpose programs – Usable for different purposes 18

Application Software Custom-Designed Applications – Advantages: Meeting the organization’s needs exactly In-house developers are sensitive to the organizational culture – Disadvantages: High cost Production schedule subject to long delays Incompatible with other organizations’ systems 19

Application Software Figure 5.6 Advantages and disadvantages of custom applications 20

Application Software Packaged Software – Advantages: Low cost High quality Vendor support Immediate availability – Often tested at user sites (alpha sites and beta sites) before the final version is released. 21

Application Software Figure 5.7 Advantages and disadvantages of packaged software 22

Applications Software Packaged General Purpose Software – Word processors – Electronic spreadsheets – Database management systems 23

Packaged Software Figure 5.8 Electronic spreadsheets are powerful tools for (a) tabulation, (b) manipulation, and (c) data analysis. 24

Packaged Software Multimedia – Can handle many different types of data such as text, voice, and image. – Powerful means of communicating. – Uses include education, training, research, and business. 25

Packaged Software Virtual Reality (VR) – 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. 26

System Software Manages computer resources and performs routine tasks not specific to any application – Copying and pasting sections and files – Printing documents – Controlling hardware functions – Allocating memory Developed to partner with application software 27

System Software Operating Systems (O/S) – Most important system software Developed for a certain microprocessor or microprocessors Addresses technical details such as registers and RAM addresses. Plays the role of “traffic cop” or the “boss” of computer resources. 28

System Software Figure 5.9 The operating system mediates between applications and the computer, and controls peripheral devices. 29

System Software Figure 5.10 Computers operate on a number of layers, starting from the user interface and moving inward to the hardware. 30

System Software Figure 5.11 Popular operating systems 31

System Software – Operating System Functions Systems Management User Interface Memory Allocation Multitasking, Multiprogramming, and Multiprocessing Times and Statistics Increasing Services from O/Ss 32

System Software Compilers and Interpreters – 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 times Converts into object code and executes 33

System Software Figure 5.12 A compiler converts higher-level language code (source code) into machine language (object code), which the computer can process. 34

System Software Data Communication Programs – 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 35

System Software Proprietary vs. Open Source – 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. 36

Considerations in Purchasing Software Figure 5.13 Sample software evaluation form 37

Considerations in Purchasing Software Figure 5.14 Sample results of software evaluation (5 is the highest score.) 38