Chapter_3_System Acquisition and development.pdf
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Kingdom of Saudi Arabia Ministry of Higher Education Al-Imam Muhammad Ibn Saud Islamic University College of Computer and Information Sciences Foundations of Information Systems IS201 Dr. Nujud Aloshban IS 201 Foundatio...
Kingdom of Saudi Arabia Ministry of Higher Education Al-Imam Muhammad Ibn Saud Islamic University College of Computer and Information Sciences Foundations of Information Systems IS201 Dr. Nujud Aloshban IS 201 Foundations of Information Systems Kingdom of Saudi Arabia Ministry of Higher Education Al-Imam Muhammad Ibn Saud Islamic University College of Computer and Information Sciences Principles of Information Systems, Thirteenth Edition IS1100 Chapter 12 System Acquisition and development IS 201 Foundations of Information Systems Buy Versus Build g Buying off-the-shelf software is less risky and leads to quicker deployment Maintenance and support costs may become expensive g i · Loading… sigil S : &D & Organizations can use several different approaches when developing their software & , 5o The waterfall and agile software development processes will be discussed in / this chapter 9 % IS 201 Foundations of Information Systems 0 Waterfall system development process Waterfall system development process A sequential, multistage system development process Work on the next stage cannot begin until the results of the current stage are reviewed and approved or modified as necessary There are six phases: Investigation Analysis 5) - Design Construction Integration Testing and implementation IS 201 Foundations of Information Systems 0 Waterfall system development process Waterfall W IS 201 Foundations of Information Systems 0 Waterfall system development process IS 201 Foundations of Information Systems 0 System Investigation System investigation Initial phase in the development of a new or modified business information system whose purpose is to gain a clear understanding of the specifics of the problem to solve or the opportunity to address Steps of the investigation phase 1. Review systems investigation request 2. Identify and recruit team leader and team members 3. Develop budget and schedule for investigation 4. Perform investigation & 5. -9/19 Perform preliminary feasibility analysis 6. Prepare draft of investigation report 7. Review results of investigation with steering team 535) makers decision IS 201 Foundations of Information Systems 0 System Investigation Review System Investigation Request A systems investigation request includes: A preliminary statement of the problem or opportunity to be addressed A brief discussion of how this effort aligns with previously defined company and organization objectives, goals, and strategies Identification of the general areas of the business and business processes to be included in the scope of the study Identify and Recruit Team Leader and Team Members A leader is identified and recruited after managers grant approval to initiate systems investigation ↑ Investigation team members chosen next Investigation team responsibilities Gather and analyze data Prepare an investigation phase report Present results to the project steering team IS 201 Foundations of Information Systems 0 System Investigation Develop Budget and Schedule for Investigation The team develops a list of specific objectives and activities to accomplish along with a schedule for completing the work The team establishes major milestones to help monitor progress A budget is prepared including travel expenses and funds for consultants Perform Investigation Refine the initial problem definition and scope described in the systems investigation request Loading… Identify the high-level business requirements the system must meet Identify any issues or risks associated with the project Joint Application Development A structured meeting process that can accelerate and improve the efficiency and effectiveness of the investigation, analysis, and design phases of a systems development project Functional Decomposition A technique used during the investigation, analysis, and design phases to define the business processes included within the scope of the system IS 201 Foundations of Information Systems 0 System Investigation ↑ joint Application development 7.. - - - - s IS 201 Foundations of Information Systems 0 System Investigation * IS 201 Foundations of Information Systems 0 System Investigation Perform Preliminary Feasibility Analysis Components of the feasibility analysis Technical feasibility: examines whether a project is feasible within the current limits of available technology Economic feasibility: determines whether the expected benefits associated with the project outweigh the expected costs sufficiently to make the project financially attractive Legal feasibility: the process of determining whether laws or regulations may prevent or limit a system development project Operational feasibility: the process of determining how a system will be accepted by people and how well it will meet various system performance expectations Schedule feasibility: the process of determining whether a project can be completed within a desired time frame IS 201 Foundations of Information Systems 0 System Investigation Prepare Draft of Investigation Report A systems investigation report that summarizes the results of the systems investigation and recommends a course of action Possible actions Continue on into systems analysis Modify the project in some manner and perhaps repeat the systems investigation Drop the project altogether IS 201 Foundations of Information Systems 0 System Investigation Report IS 201 Foundations of Information Systems 0 System Investigation Review Results of Investigation with Steering Team The systems investigation report is reviewed with the steering team to gain their input and counsel Input is used to finalize the systems investigation report IS 201 Foundations of Information Systems 0 System Analysis The overall emphasis of system analysis is on: Gathering data on the existing system Determining requirements for the new system Considering alternatives within identified constraints Investigating the feasibility of alternative solutions Steps in the systems analysis phase 1. Identify and recruit team leader and team members 2. Develop budget and schedule for systems analysis activities 3. Study existing system 4. Develop prioritized set of requirements 5. Identify and evaluate alternative solutions 6. Perform feasibility analysis 7. Prepare draft of systems analysis report 8. Review results of systems analysis with steering team IS 201 Foundations of Information Systems 0 System Analysis Identify and Recruit Team Leader and Team Members Some members of the original investigation team participating in the systems analysis provide project continuity Develop Budget and Schedule for System Analysis Activities The team develops a list of specific objectives and activities required to complete the systems analysis is developed along with a schedule The team establishes major milestones to track progress A budget is prepared including travel expenses and funds for outside resources IS 201 Foundations of Information Systems 0 System Analysis Study Existing System Identify the strengths and weaknesses of the existing system Examine current inputs, outputs, processes, security and controls, and system performance Data collection methods JAD sessions Direct observation Surveys IS 201 Foundations of Information Systems 0 System Analysis Develop Prioritized Set of Requirements Priority categories Critical Medium priority Low priority JAD sessions provide an effective way to define system requirements Ask managers to produce a list of critical success factors (CSFs) Processes must be further defined and individuals/organizations responsible for process steps identified Data-flow diagrams (DFDs) provide a model of a proposed new system IS 201 Foundations of Information Systems 0 System Analysis IS 201 Foundations of Information Systems 0 System Analysis Develop Prioritized Set of Requirements (cont’d) Data modeling defines: Databases the system will draw from New databases the system will create Entity-relationship (ER) diagrams show logical relationships among data entities Security and Control System Performance Factors in determining system performance Timeliness of output Ease of use Scalability System response time Availability Reliability IS 201 Foundations of Information Systems 0 System Analysis IS 201 Foundations of Information Systems 0 System Analysis Identify and Evaluate Alternative Solutions The analysis team must think creatively and consider several system solution options Pareto principle (80–20 rule): An observation that for many events, roughly 80 percent of the effects come from 20 percent of the causes. Perform Feasibility Analysis An in-depth feasibility analysis is done for each of the candidate solutions the team wants to consider Prepare Draft of System Analysis Report Systems analysis concludes with a formal systems analysis report summarizing the findings of this phase of the project Review Results of System Analysis with Steering Team The systems analysis report is presented to the project steering team with a recommendation to stop, revise, or go forward with the systems development project The project sponsor and the steering team must formally approve of any changes IS 201 Foundations of Information Systems 0 System Analysis IS 201 Foundations of Information Systems 0 System Design System design creates a complete set of technical specifications that can be used to construct the information system Steps in the systems design phase 1. Identify and recruit team leader and team members 2. Develop schedule and budget for systems design activities 3. Design user interface 4. Design system security and controls 5. Design disaster recovery plan 6. Design database 7. Perform feasibility analysis 8. Prepare draft of systems design report 9. Review results of systems design with steering team IS 201 Foundations of Information Systems 0 System Design Identify and Recruit Team Leader and Team Members Some members of the systems analysis team participating in the systems design ensure project continuity Develop Schedule and Budget for System Design Activities The systems design team develops a list of specific objectives and activities required to complete the systems design The group prepares a budget for completing the systems design Design User Interface How the user experiences the information system determines whether the system will be accepted and used User interface design integrates concepts and methods from computer science, graphics design, and psychology to build interfaces that are accessible, easy to use, and efficient IS 201 Foundations of Information Systems 0 System Design Design System Security and Controls Specific system security and controls must be developed for all aspects of the information system Hardware Software Database systems Loading… Telecommunications Internet operations IS 201 Foundations of Information Systems 0 System Design Design Disaster Recovery Plan Disaster recovery plan A documented process to recover an organization’s business information system assets including hardware, software, data, networks, and facilities in the event of a disaster Mission-critical processes play a pivotal role in an organization’s continued operations and goal attainment IS 201 Foundations of Information Systems 0 System Design Design Database Steps in designing a database A schema and is entered into the DBMS using a data definition language A data dictionary is established Choose a vendor Final evaluation begins with a detailed investigation of the contenders’ proposals Vendors should make a final presentation including a performance evaluation test Perform Feasibility Analysis Reassess the technical, economic, legal, operational, and schedule feasibility based on results of system design findings IS 201 Foundations of Information Systems 0 System Design Prepare Draft of System Design Report Systems design concludes with a formal systems design report summarizing the findings of this phase of the project IS 201 Foundations of Information Systems 0 System Design Review Results of System Design with Steering Team The systems design report is presented to the project steering team with a recommendation to stop, revise, or go forward with the systems development project At the end of the design phase, organizations employing the waterfall system development process freeze the scope and the user and business requirements Any potential changes must go through a formal scope change process IS 201 Foundations of Information Systems 0 Construction System construction converts the system design into an operational system Steps of the system construction phase Code software components Create and load data Perform unit testing IS 201 Foundations of Information Systems 0 Integration and Testing Types of testing Integration testing System testing Volume testing User acceptance testing Integration testing Involves linking all of the individual components together and testing them as a group to uncover any defects between individual components System testing Testing the complete, integrated system to validate that the information system meets all specified requirements IS 201 Foundations of Information Systems 0 Integration and Testing Volume testing Involves evaluating the performance of the information system under varying yet realistic work volume and operating conditions Goals of volume testing are to: Determine the work load at which systems performance begins to degrade Eliminate issues that prevent the system from reaching its required performance User Acceptance Testing UAT is testing performed by trained system users to verify that the system can complete required tasks in a real-world operating environment and perform according to the system design specifications IS 201 Foundations of Information Systems 0 Integration and Testing · IS 201 Foundations of Information Systems 0 Implementation Steps involved in implementation User preparation Site preparation Installation Cutover User preparation User preparation is the process of readying managers, decision makers, employees, other users, and stakeholders to accept and use the new system Successfully introducing an information system requires a mix of organizational change skills and technical skills User training is very important IS 201 Foundations of Information Systems 0 Implementation Site Preparation Site preparation for a small system can be as simple as rearranging the furniture in an office to make room for a computer A large system might require special wiring, air conditioning, or construction Sufficient lead time should be built into the schedule to allow for site preparation Installation Installation is the process of physically placing the computer equipment on the site and making it operational IS 201 Foundations of Information Systems 0 Implementation Cutover Cutover is the process of switching from an old information system to a replacement system Direct conversion (also called plunge or direct cutover) is a high-risk approach The phase-in approach (piecemeal approach) involves slowly phasing the new system’s components as the old system’s components are phased out Pilot start-up: running a complete new system for only one group of users Parallel start-up: running both the old and new systems and comparing outputs IS 201 Foundations of Information Systems 0 Implementation IS 201 Foundations of Information Systems 0 System Operation and Maintenance Steps of the operation and maintenance phase ↳ 1. Operation Sig 2. Maintenance Gib ! Disposal 3. Operation S. Systems operation involves using the new or modified system under all kinds of operating conditions Getting the most out of the new system is the most important aspect of operation A formal help desk is beneficial for employees and customers Monitoring involves measuring system performance by tracking: The number of errors encountered, the amount of memory required, the amount of processing or CPU time needed, etc. Systems review: the process of analyzing systems to make sure they are operating as intended IS 201 Foundations of Information Systems 0 System Operation and Maintenance Maintenance Systems maintenance: a stage of systems development that involves changing and enhancing the system to make it more useful in achieving user and organizational goals. Reasons for program maintenance Poor system performance Changes in business processes Changes in the needs of system stakeholders, users, and managers Bugs or errors in the program Technical and hardware problems Corporate mergers and acquisitions S Changes in government regulations Changes in the operating system or hardware on which the application runs IS 201 Foundations of Information Systems 0 System Operation and Maintenance Four accepted categories signify the amount of change involved in maintenance Slipstream upgrade: a minor upgrade; a code adjustment or minor bug Patch: a minor change to make a correction or make a small enhancement Release: a significant program change; software documentation changes are · required Version: a major program change IS 201 Foundations of Information Systems 0 System Operation and Maintenance Disposal System disposal involves those activities ensuring the orderly dissolution of the system Steps involved in system disposal Communicate intent: all key stakeholders should be notified months in advance of the actual shutdown Terminate contracts: contact vendors well in advance to avoid penalty fees Make backups of data: follow the organization’s record management policies Delete sensitive data: wipe hard drives need to be wiped several times or physically destroy hard drives Dispose of hardware: discard in an environmentally friendly manner IS 201 Foundations of Information Systems 0 Agile Development An iterative system development process that develops the system in “sprint” increments lasting from two weeks to two months Concentrates on maximizing the team’s ability to deliver quickly and respond to emerging requirements Scrum: a method to keep the agile system development effort focused and moving quickly The scrum master coordinates all activities Extreme programming (XP) promotes incremental development of a system using short development cycles to: Improve productivity Accommodate new customer requirements IS 201 Foundations of Information Systems 0 Agile Development IS 201 Foundations of Information Systems 0 Agile Development IS 201 Foundations of Information Systems 0 Agile Development DevOps: the practice of blending the tasks performed by the development staff and the IT operations groups to enable faster and more reliable software releases Being used as part of a continuous development strategy, in which releases are launched daily IS 201 Foundations of Information Systems 0 System development IS 201 Foundations of Information Systems 0 Buying Off-the-Shelf Software IS 201 Foundations of Information Systems 0 Package Evaluation Phase Steps in the Package Evaluation Phase include: Identify potential solutions Select top contenders Research top contenders Perform final evaluation of leading solutions Make selection Finalize contract IS 201 Foundations of Information Systems 0 Package Evaluation Phase Identify Potential Solutions Project team should make a preliminary assessment of the software marketplace to determine whether existing packages can meet the organization’s needs Request for information (RFI) is a document that outlines an organization’s needs and requests vendors to respond with information about if and how they can meet those needs IS 201 Foundations of Information Systems 0 Package Evaluation Phase Select Top Contenders Project team will review information provided by vendors in response to the RFI Selection will be made based on: How well the vendor’s software appears to meet the organization’s needs Preliminary cost and timing estimates Information gleaned from references How easy the vendor has been to work with so far Research Top Contenders Begins with a detailed investigation as well as in-depth discussions with two or three customers of each contender Contenders should be asked to make a final presentation and demonstrate their solution using a performance evaluation test Conducted in a computing environment, with a workload that matches intended operating conditions IS 201 Foundations of Information Systems 0 Package Evaluation Phase Make Selection Weigh factors such as: How well the vendor’s solution matches the needs of the users and business The amount of effort required to integrate the new software with existing software Results of the performance evaluation test Relative costs (including any software modifications) and benefits The technical, economic, legal, operational, and schedule feasibility Input from legal and purchasing resources on the legal and financial viability of the contender Feedback from customers on how well the software performs as well as on the quality of the support provided by the vendor IS 201 Foundations of Information Systems 0 Finalize Contract Develop a fair contract when acquiring new computer hardware or software Allow at least two months for review and negotiation of a final contract Take special precautions in signing contracts with the service provider of cloud-computing or software-as-a-service Contract should have provisions for: Monitoring system modification quality and progress Ownership and property rights of the new or modified system Contingency provisions in case something doesn’t work as expected Dispute resolution if something goes wrong IS 201 Foundations of Information Systems 0 Integration and Testing Types of testing Integration testing System testing Volume testing User acceptance testing IS 201 Foundations of Information Systems 0 Implementation Key implementation tasks include: Use data-flow diagrams to map current business processes and requirements to the software, and identify any gaps that must be filled by changing current processes or by modifying the software. Install the software and configure all of its capabilities and options to meet the project requirements. Customize any aspects of the solution needed for the organization. Integrate existing software with the new software. Train end users. Test the software to ensure that it meets all processes and requirements. Convert historical data from the old software so that it can be used by the new software. Roll out the new software to users in a live work environment. Provide for ongoing end-user support and training. IS 201 Foundations of Information Systems 0 Summary Organizations can obtain software using one of two basic approaches: buy or build A system under development following the waterfall approach moves from one phase to the next, with a management review at the end of each phase Agile development is an iterative system development process that develops a system in “sprint” increments lasting from two weeks to two months When buying off-the-shelf software, the effort required to modify the software package as well as existing software so that they work well together must be taken into account as a major factor in selecting the final vendor and software IS 201 Foundations of Information Systems 0
