IT Chapter Seven 2024-2025 PDF

Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  CHAPTER 7 An Introduction to Acquiring and Developing BIS Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Learning objectives: After Studying this chapter Students should be...

Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  CHAPTER 7 An Introduction to Acquiring and Developing BIS Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Learning objectives: After Studying this chapter Students should be able to understand the following aspects: L O 1 Introduction L O 2 How and Why are Information Systems Acquired? L O 3 Software Acquisition and the Systems Development Lifecycle L O 4 Rapid Application Development and Prototyping. L O 5 Purchase of an Off-the-shelf Package L O 6 User-developed Applications Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 1: Introduction This objective covers the following points: 1.1- BIS acquisition 1.2- Systems development lifecycle (SDLC) 1.3- SDLC stages Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 1.1- BIS acquisition: - BIS acquisition describes the method of obtaining an information system for a business. - It is the process of evaluation and implementation of BIS. The main choices of BIS acquisition are: * Off-the-shelf (packaged); * Bespoke (tailor-made) applications developed by an in-house IT department or a software house; and * Systems that are end-user-developed (i.e., by non- IS/IT professionals). Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 1.2- Systems development lifecycle (SDLC): - Any information systems project follows a logical series of development phases. These are known as the systems development lifecycle. 1.3- SDLC phases (stages): - Any BIS project follows a logical series of development phases. Typical stages are: ** Initiation, ** feasibility study, ** analysis of business requirements, ** systems design, ** system build and implementation, and, finally, ** review and maintenance. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 2: How and Why are Information Systems Acquired? This objective covers the following parts: Part 1: Methods for acquiring the information systems: 2.1- Bespoke development 2.2- Purchasing ‘off-the-shelf’ software 2.3- User-developed software 2.4- Hybrid approaches to systems acquisition Part 2: Factors affecting software acquisition Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Part one: Methods for acquiring the information system: - There are three main methods (alternatives) for acquiring the information systems necessary to support a particular business need. These are: ** bespoke development, ** off-the-shelf software, and ** end-user development. Figure 7.2, P.251 summarizes these three alternatives. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 1- Bespoke development: - Bespoke development is the term used when information systems are developed ‘from scratch’ by one or more IS professionals to meet the business requirements of the application. - Here new BIS will be developed from scratch by a team of IS professional. ** The team will either work for business, in which case we refer to this as ‘in-house’ bespoke development, or ** for a third party such as a software house, in this case we say that the software development has been ‘outsourced ’. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Benefits of bespoke development: Bespoke development has the following benefits : ** It produces software tailored to the precise requirements of the business. ** The development of bespoke information systems may confer (grant) specific competitive advantage since competitor organizations do not have the same software solutions. Difficulties of bespoke development: Expense: Bespoke development is the most expensive way of developing new information systems. Time: Bespoke development, especially when using formal structured methodologies, is popular for time overruns, usually with delays of months or years. Quality: Bespoke is usually not free from bugs. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 2.2- Purchasing ‘off-the-shelf’ software: - Off-the-shelf purchase of packaged software is an acquisition method that involves direct purchase of a pre- written application used by more than one company. - The major disadvantages of off-the-shelf software are: ** It may require businesses to process information in a particular way that is different from the way they normally do business. ** A certain off-the-shelf software package may not offer sufficient features. - The major benefit, however, of off-the-shelf software packages is their low cost when compared to acquiring bespoke software with the same level of functionality. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 2.3- User-developed software: User-developed software is software written by non-IS professionals, namely the business users. - The main features of user-developed software are: ** End-user- applications are more limited in scope, ** Applications may be departmental or personal in nature, and ** They are usually output- or report-oriented rather than input-driven. - Note that these applications may be written either by IT professionals or by the end-users themselves. If the latter is the case, they are often referred to as user- developed applications. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 2.4- Hybrid approaches to systems acquisition: - The approaches to systems acquisition described above are not mutually exclusive to a given project or within an organization. - Where the software is generic to all businesses, as is the case with systems software and office productivity packages, off-the-shelf software will be purchased. - Where the business has more specific needs and wishes to achieve a competitive advantage, bespoke and tailored approaches to acquisition will be used. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Part two: Factors affecting software acquisition: - There are a number of factors that will influence the choice of acquisition method. - Three critical ones are time, cost and quality considerations. - The different acquisition options have different strengths when considered in terms of the three critical criteria. Table 7.1, shows how the alternatives compare in terms of these three criteria. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Note that the quality of the delivered product is considered from two aspects: ** the number of bugs or errors found, and ** the suitability of the software in meeting the requirements of the business user. Other factors affecting software acquisition include the following: ** Organization size. ** In-house IS/IT expertise. ** Complexity of the required information system. ** Uniqueness of the business or business area to be supported. ** IS/IT expertise among end-users. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 3: Software Acquisition and The Systems Development Lifecycle This objective covers the following points: 3.1- Initiation 3.2- Feasibility assessment 3.3- Systems analysis 3.4- Systems design 3.5- System build 3.6- System implementation and changeover 3.7- Review and maintenance Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved - The SDLC approach recognizes that systems are developed in a series of steps or phases and that each phase needs to be completed before the next one starts. - Recognition is also given to the fact that the programming activity (part of the build phase) should only start once user requirements have been determined and the systems design produced. Figure 4.7, P.256 illustrates the normal steps found in the SDLC. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved - The basic steps that most systems development projects follow are: 3.1- Initiation: - The initiation phase is the startup phase and is the first phase in an information system (IS) development project. - Its aims are to establish whether the project is feasible and then prepare to ensure the project is successful. - The initiation phase context is as follows: Input: creative thought and/or systematic evaluation of IS needs. Output: idea for initiation of a new information system. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Note that: The source of this initiation process may be one of the following: ** Management director or other senior management. ** Information systems department. ** Functional business area. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 3.2- Feasibility Study (assessment): - Feasibility study is the activity that occurs at the start of the project to ensure that the project is a viable business proposition. - The feasibility report analyzes the need for and impact of the system and considers different alternatives for acquiring software. The feasibility study context is as follows: Input: idea for initiation of new information systems. Output: feasibility report and recommendation to proceed. - The feasibility assessment can be considered to be part of the initiation phase. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved - It will establish whether computer-based information systems fit certain feasibility criteria. Three criteria are usually cited: 1. Technical feasibility: - To be technically feasible, either the technology exists, or it can be created to support the required system. 2. Economic feasibility: - Economic feasibility means that information systems must generate more benefits than the cost needed to produce them. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 3. Operational and organizational feasibility: - Assuming that the proposed information systems are both technically and economically feasible, an assessment must be made of whether the project is operationally and organizationally feasible. - By operationally feasible, we mean that the system must be capable of performing within the required speed, volume, usability and reliability parameters. - Organizational feasibility considers how closely the proposed information system will match the needs of the organization. It will also involve a review of how the system users’ skill sets and attitudes will affect the system. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 3. Systems analysis: - Systems analysis is the capture of the business requirements of a system from: ** talking to or observing end-users, and ** using other information sources such as existing system documentation. - The systems analysis context is as follows: Input: terms of reference in feasibility report describing outline requirements. Output: detailed requirements specification summarizing system functions. Supported by diagrams showing the information flow and processes that are required. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved - Once a proposed system is agreed to be feasible, it is necessary to carry out the detailed work of assessing the precise requirements that the intended users have for the new system. - Note that the systems analysis step is sometimes referred to as the “ requirement determination” step or the “system study” step. There are three main tasks within this phase: First, it is necessary to gain an understanding of how the current information systems (computerized or paper- based) work. Secondly, a diagrammatic model of the current system workings is produced to ensure that IT professionals and system users are in agreement. Finally, a set of requirements for the new information system is produced. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved The requirements specification will define: - The features that the new system is required to contain (for e.g. the ability for end-users to be able to design their own reports); - The scope of the system under consideration (e.g. is the system intended for just one functional area of the business or is it to embrace all business activities?); - The intended users of the new system; - System performance standards, including response times, batch processing times (if required) and reliability needs; - Environmental requirements such as physical working environment, operating system and hardware on which the system will run. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 4- Systems design: - The systems design phase defines how the system will work in key areas of user interface, program modules, security and database transactions. The systems design context is as follows: Input: requirements specification. Output: detailed design specification. Note that systems design is broader in scope and will deal with such matters as: choosing an appropriate database management system; establishing general systems security standards; Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  general standards for printed report production; screen design standards for input and output; data capture requirements; data storage requirements. Note that: Detailed design, on the other hand, will result in a blueprint for individual system modules which will be used in the system build phase that follows. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5. System build: - System build is the creation of software by programmers. - It involves: ** writing the software code (programming), ** building release versions of the software, ** constructing and populating the database and testing by programmers and end-users. - Note that: Writing of documentation and training may also occur at this stage. - The system build context is as follows: Input: requirements and design specification. Output: working software, user guides and system documentation. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Note that: ** If during the build phase it appears from testing that the system does not meet the original requirements as determined during the analysis step, then it will be necessary to revisit the design step to see whether any errors were made in interpreting the systems requirements. - If the design brief was correctly interpreted but the system still contains errors in the delivery of the perceived requirements, it will be necessary to revisit the analysis step to determine the systems requirements more precisely. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6- System implementation and changeover: - System implementation covers practical issues such as: ** making sure the hardware and network infrastructure for a new system are in place; ** testing of the system; and also ** human issues of how best to educate and train staff who will be using or affected by the new system. - Note that implementation also involves the transition or changeover from the old system to the new. - The system implementation context is as follows: Input: working system, not tested by users. Output: signed-off, operational information system installed in all locations. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 7- Review and maintenance: - Once the system is operating under live running conditions, it will be inevitable that changes will be required over time. - The maintenance phase involves two different types of maintenance. - The first, known as ‘unproductive maintenance’, stems from errors or oversights in the original systems development which, while: ** not preventing the system operating to an acceptable level, and ** are still necessary to correct for it to conform with the original specification. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved - The second form of maintenance involves the addition of new features and facilities that extend the scope and functionality of the information system. - Note that an activity known as the Post-implementation review should also be undertaken. - Post implementation review is a meeting that occurs after a system is operational to review the success of the project and learn lessons for the future. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 4: Rapid Application Development (RAD) and Prototyping This objective covers the following points: 4.1- Traditional methods disadvantages 4.2- Rapid Application Development 4.3- Prototyping Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 4.1- Traditional methods disadvantages: - The evidence from project failures has implied that traditional structured methodologies such as the SDLC have a tendency to deliver systems that arrive too late and therefore no longer meet their original requirements. Traditional methods can fail in a number of ways: 1- A gap of understanding between users and developers: - Users tend to know less about what is possible and practical from a technology perspective, while developers may be less aware of the underlying business decision- making issues which lie behind the systems development requirement. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 2- Tendency of developers to isolate themselves from users. 3- Quality measured by closeness of product to specification. - The system should not do exactly what the specification said. - The real focus should be on a comparison of the deliverables with the requirements, rather than of deliverables with a specification that was a reflection of a perceived need at a particular point in time. 4- Long development times. 5- Business needs change during the development process. 6- What users get is not necessarily what they want. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 4.2- Rapid Application Development (RAD): - Rapid applications development (RAD) is a possible solution to the traditional SDLC problems and pressures. This uses prototyping to involve users and increase development speed. - Rapid applications development (RAD) is a method of developing information systems which uses prototyping to achieve user involvement and faster development. - The result of the RAD approach should be new information systems that more closely meet the requirements of the intended users, because the requirements will not have changed significantly over a relatively short development timescale. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 4.3- Prototyping: - A Prototype is a preliminary version of part or a framework of all of the information systems which can be reviewed by end-users. - Prototyping is an iterative process where users suggest modifications before further prototypes and the final information system is built. - Note that With prototyping, all the phases within the SDLC are still present, but the activities of analysis, design, test and review will be repeated within the prototyping phase. Figure 7.5, P.261 gives a more realistic representation of systems development. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 5: Purchase of an off-the-shelf package This objective covers the following point: 5.1- SDLC application for packaged software. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software: - The traditional SDLC model was discussed in the context of a system that is being acquired using a bespoke development approach. - However, as we have seen, there are methods of information system (IS) acquisition that do not require the development of bespoke solutions. - For packaged software, the application of the SDLC stages would typically be as follows: Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software: 1- Initiation - This step clearly applies regardless of the acquisition method. - There must be some kind of stimulus which creates the idea that a computer-based information system is needed to respond to a business opportunity or problem. 2- Feasibility - This step also must be followed regardless of the acquisition method. - Indeed, it is during the feasibility step that an investigation will be undertaken into the technical aspects of the required system and a make-or-buy decision will be made. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) - A ‘buy’ decision indicates that a solution is probably available off the shelf; - A ‘make’ decision indicates that a bespoke solution is probably required. 3- Analysis - This is an important step in the acquisition of off-the- shelf software as it is in building bespoke software solutions. - System requirements must be determined and catalogued so that they can be compared with the features offered by the package. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) - Part of the analysis exercise, therefore, will be to determine the extent to which a software package may be configured to meet the organization's needs. 4- Design - It is here that significant differences are found when compared with bespoke software design. - An off-the-shelf package will have been designed with many different businesses in mind and will offer a range of features to satisfy most requirements. - The ‘how’ aspect of software acquisition has, therefore, already been determined and the system subsequently built. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) - The task for the purchaser of an off-the-shelf package is to compare the design features required against those offered by different packages. 5- Build - With an off-the-shelf package, the system has already been built by the vendor. - As part of the feature set offered by a package, there may be an ability to customize aspects of the software product by setting certain parameters. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) For example, an accounting package may be set up either to interface with a sales order processing system from the same vendor, or to offer the ability to interface with a package offered by another supplier or with a bespoke system. - There will also need to be a testing phase where all the relevant features of the package are run in a simulated live environment. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) 6- Implementation/changeover - As with a bespoke software solution, data will have to be converted or entered from old computer- or paper- based information system. - One of the benefits of purchasing off-the-shelf software is that the product should be free from major bugs and errors. - The purchaser should be confident, therefore, that the software product will work as specified from the outset (start). Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 5.1- SDLC application for packaged software (Continued) 7- Maintenance and review - Maintenance and enhancements of the software will differ from those in a bespoke solution. - Whereas bespoke software can be enhanced over time by the developer (either in-house or by a third party), an off-the-shelf enhancements to the package will differ in a number of ways: ** Enhancements to the package will normally be made available by the vendor as a new release. - As with the bespoke solution, a post-implementation review should be undertaken. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved  Learning Objective 6: User-Developed Applications This objective covers the following points: 6.1- What is a user-developed application? 6.2- SDLC application for User-developed software Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6.1- What is a user-developed application? The main features of user-developed software (applications) are: ** User developed Software (applications) are software written by non-IS professionals, (i.e., the business users). ** User-developed software (applications) ‘should’ be developed in line with the steps normally covered during the bespoke development process. ** The main difference is that end-user-developed applications are usually on a much smaller scale than those developed for corporate use. - The steps for developing user-developed application are: Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6.2- SDLC application for User-developed software (Continued). 1- Initiation - The stimulus for end-user information system development will typically come from a personal or departmental requirement which can be satisfied by employing easy-to-use end-user development tools. 2- Feasibility. - Part (aspect) of the feasibility exercise is for the user to be sure that the necessary and appropriate end-user development tools exist or can be acquired in order to proceed with the development. - A second aspect is an analysis of the cost involved in end-user developed software. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6.2- SDLC application for User-developed software (Continued). 3- Analysis - One of the benefits is that an end-user do not need to present information systems requirements to an IS/IT specialist for subsequent development. - This therefore reduces the risk of mistranslating information systems requirements and increases the probability that the developed system is what the user actually wants. 4- Design - End-user-developed software has a tendency to be developed more on a ‘trial and error’ basis than through the use of formal design techniques. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6.2- SDLC application for User-developed software (Continued). - When it works well, this can result in the faster development of applications software. 5- Build. - Recent improvements in the availability of inexpensive development tools such as Visual Basic for the PC have made it much easier for the end-user developer to build systems without turning to difficult programming techniques. 6- Implementation/changeover - This step is less critical than for company-wide information systems. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved 6.2- SDLC application for User-developed software (Continued). - Data are either locally generated or extracted from central databases, where it can be assumed that the data are validated and verified as correct. 7- Maintenance and review - All software has to be maintained in some way. - In many respects, the maintenance of end-user- developed software is more problematic than for other forms of software acquisition. - This is because end-user-developed systems are often not documented, and they may employ obscure (unknown) techniques in their construction. Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved END of CHAPTER SEVEN Copyright 2019, 2015,2008 Pearson Education, Inc. All Rights Reserved