CSC340 Information Systems Analysis and Design page 1 10 University of Toronto Faculty of Arts and Science Dept of Computer Science CSC340F Information Systems Analysis and Design December 2002 Instructor Steve Easterbrook No Aids Allowed Duration 2 hours Make sure your examination booklet has 10 pages including this one Write your answers in the space provided This examination counts for 35 of your final grade Name Please underline last name Student Number Question Marks 1 20 2 20 3 20 4 20 5 20 Total 100 CSC340 Information Systems Analysis and Design page 2 10 1 Short Questions 20 marks total a Software Lifecycles 5 marks Name two alternatives to the waterfall model What are the advantages and disadvantages of each model when used to manage a software development project Spiral model Advantages allows for iterative development with prototyping and risk management built in to the process Disadvantages Might be expensive and slower to do lots of iterations Not clear what happens if there are unexpected changes in business priorities Incremental development Advantages don t need to understand all the requirements before developing the first version Lessons from early versions feed into later versions Disadvantages hard to plan for versions beyond the first Lessons from early versions might be learnt too late Might mislead customer if first version doesn t match many of their requirements Notes Other possible lifecycles models include Incremental development prototyping V model Must have both advantages and disadvantages for two different models to get full marks b Software Architectures 5 marks Layered software architectures can be used to reduce coupling between the functions of a system that are closer to the machine and those that are closer to user needs Why is this reduced coupling useful Describe a typical layered architecture and explain the role of each of the layers Reduced coupling is good because it separates the core functions e g business logic from functions that are platform dependent e g data storage and also from how the system interacts with users e g the user interface This is good for Modifiability changes can be made at one layer without affecting others Reusability layers can be reused in similar systems Understandability easier to understand how the software works Must have at least two advantages Typical layered architecture has three layers Presentation layer is responsible for the user interface Includes classes to accept input from the user display results and manage the appearance of the interface Business Logic layer implements the basic functions provided by the system Includes all the entity classes and control classes needed to implement the use cases Data storage layer is responsible for persistent storage of the information users in the system Includes a database component or other mechanism to retain and query the data Notes other possible answers 2 layers essentially client server 4 layers model splits business logic layer into application layer responsible for controlling the use cases and domain entity layer for basic functions shared by different applications CSC340 Information Systems Analysis and Design page 3 10 c Legal Issues 5 marks Under copyright law at what point is information considered to be copyrighted Suggest two ways in which copyright law can affect an information systems analysis project and in each case explain the professional responsibility of the analyst Under copyright law information is considered to be copyrighted as soon as it is fixed in a tangible medium e g written down entered into a computer system etc whether or not a copyright notice is included 1 Copyright law can affect an information systems project because some of the information e g pictures text etc to be stored by the system may be copyrighted If the system provides wide access to this information it may infringe the copyright of the owner of the information It is the responsibility of the analyst to check whether copyright protection might apply to any of the information to be stored in the system to explain to the customer all such issues and to secure agreement of the copyright owner when necessary or propose a design that avoids the copyright infringement 2 Another way in which copyright law can affect a project is that information to be used for the analysis e g source documents photos etc might be copyrighted In this case including them in reports written for the customer may infringe the copyright It is the responsibility of the analyst to check the copyright of any source material and secure permission to use it before including it Notes other suggestions are possible give credit for sensible suggestions as long as analyst s responsibilities are identified d Specifications 5 marks Project managers sometimes regard work put into writing high quality specifications as gold plating and claim that it is unnecessary as it doesn t contribute to producing program code Under what circumstances is this view sensible and under what circumstances is it foolish In the latter case how would you persuade such a manager that the specification actually does need to be high quality This view is sensible for small projects where there is a well understood problem to be solved and where the analysts exploring the requirements will also implement the system i e the specification does not have to bridge this gap This view is foolish for big projects where there is a large team and lots of stakeholders In this setting proper communication among the team and with the stakeholders is important and the specification is used to make sure everyone understands the problem fully Higher quality specs should result in easier integration and higher quality software If the list of benefits above doesn t convince the manager then one could look for articles and research reports that describe the role of a high quality specification in large projects One could also use anecdotal evidence from past projects e g identify problems on a previous project that could have been avoided with a good specification Notes give credit for any reasonable suggestions for how to persuade the manager CSC340 Information Systems Analysis and Design page 4 10 2 StateChart Diagrams 20 marks The Verging Record Company VRC is planning a new information system to assist with the creation and distribution of CDs Draw a statechart diagram to represent the following behaviour of an object representing a CD
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