CSC340 Information Systems Analysis and Design page 1/10University of TorontoFaculty of Arts and ScienceDept of Computer ScienceCSC340F – Information Systems Analysis and DesignDecember 2002Instructor: Steve EasterbrookNo Aids AllowedDuration: 2 hoursMake sure your examination booklet has 10 pages (including thisone). Write your answers in the space provided.This examination counts for 35% of your final gradeName: _______________________________________________________(Please underline last name)Student Number:_______________________________________________Question Marks1 ______________/202 ______________/203 ______________/204 ______________/205 ______________/20Total___________/100CSC340 Information Systems Analysis and Design page 2/101. [Short Questions; 20 marks total](a) [Software Lifecycles – 5 marks] Name two alternatives to the waterfall model. Whatare the advantages and disadvantages of each model when used to manage a softwaredevelopment project?Spiral model.Advantages: allows for iterative development, with prototyping and risk management builtin 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 firstversion. Lessons from early versions feed into later versions. Disadvantages: hard to planfor versions beyond the first. Lessons from early versions might be learnt too late. Mightmislead 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 getfull marks.](b) [Software Architectures – 5 marks] Layered software architectures can be used toreduce coupling between the functions of a system that are closer to the machine and those thatare closer to user needs. Why is this reduced coupling useful? Describe a typical layeredarchitecture and explain the role of each of the layers.Reduced coupling is good because it separates the core functions (e.g. business logic) fromfunctions that are platform dependent (e.g. data storage) and also from how the systeminteracts with users (e.g. the user interface). This is good for:Modifiability – changes can be made at one layer without affecting othersReusability – layers can be reused in similar systemsUnderstandability – 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 inputfrom the user, display results, and manage the appearance of the interfaceBusiness Logic layer implements the basic functions provided by the system. Includes allthe entity classes, and control classes needed to implement the use cases.Data storage layer is responsible for persistent storage of the information users in thesystem. 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 splitsbusiness logic layer into application layer (responsible for controlling the use cases) anddomain 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 consideredto be copyrighted? Suggest two ways in which copyright law can affect an information systemsanalysis 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 atangible medium (e.g. written down, entered into a computer system, etc), whether or not acopyright notice is included.1) Copyright law can affect an information systems project because some of theinformation (e.g. pictures, text, etc) to be stored by the system may be copyrighted. Ifthe system provides wide access to this information, it may infringe the copyright of theowner of the information. It is the responsibility of the analyst to check whethercopyright protection might apply to any of the information to be stored in the system, toexplain to the customer all such issues, and to secure agreement of the copyright ownerwhen 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 usedfor the analysis (e.g. source documents, photos, etc) might be copyrighted. In this caseincluding them in reports written for the customer may infringe the copyright. It is theresponsibility of the analyst to check the copyright of any source material, and securepermission to use it before including it.[Notes: other suggestions are possible, give credit for sensible suggestions, as long asanalyst’s responsibilities are identified.](d) [Specifications – 5 marks] Project managers sometimes regard work put into writinghigh quality specifications as “gold plating”, and claim that it is unnecessary as it doesn’tcontribute to producing program code. Under what circumstances is this view sensible, andunder what circumstances is it foolish? In the latter case, how would you persuade such amanager 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 besolved, 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 isimportant, and the specification is used to make sure everyone understands the problemfully. 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 articlesand research reports that describe the role of a high quality specification in largeprojects. One could also use anecdotal evidence from past projects (e.g. identify problemson a previous project that could have been avoided with a good specification).[Notes: give credit for any reasonable suggestions for how to persuade the
View Full Document
Unlocking...