QUESTION AND ANSWERS IN SOFTWARE ENGINEERING

CIT 745-SOFTWARE ENGEERING

TUTORIAL QUESTIONS

Question one

a)      In what ways do functional requirement differ from non functional requirements.

Solution

Ø  Non functional requirement is the type of requirements which Concerned with how well the system perform. It shows   how the software will do it. For example response times, volumes of data, security considerations, software performance requirements, software external interface requirements, design constraints, and software quality attributes. Nonfunctional requirements are difficult to test; therefore, they are usually evaluated subjectively. Examples of Non Functional requirements include safety, security, usability, reliability and performance requirements.

Ø  Functional requirements define what the system or application must do specifically in the context of an external interaction with a user, or with another system. These requirements depend on the type of software being developed, the expected users of the software and the general approach taken by the organization when writing requirements. It involves processes, interfaces with users and other systems and what the system must hold data about.When expressed as user requirements, the requirements are usually described in a fairly abstract way. However, functional system requirements describe the system function in detail, its inputs and outputs, exceptions, and so on.

b)      Briefly explain three (3) three aspects of functional requirements which might be taken into consideration when modeling an information system.

Solution

Ø  processes

Ø  Interfaces with users and other systems such as forms how users interact example entering data

Ø  what the system must hold data about

Question two

Ø  Interviewing is one of the primary ways to gather information about an information system. A good system analyst must be good at interviewing and no project can be conduct without interviewing. Most projects use this technique at the stage in fact finding when in-depth information is required

Ø  Questionnaires have the advantage of gathering information from many people in a relatively short time and of being less biased in the interpretation of their results. It involves  when views of large numbers of people need to be obtained, when staff of organization are geographically dispersed, for systems that will be used by the general public and a profile of the users is required

Ø  Observation. Analyst are not always very reliable informants, even when they try to be reliable and tell what they think is the truth. This is required when  quantitative data is required ,to verify information from other sources, when conflicting information from other sources needs to be resolved and when a process needs to be understood from start to finish

Ø  Background Reading. analyst is not familiar with organization and initial stages of fact finding

Question three

Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non functional.

Solution

Engineer would have to make a Systems Requirements Document. An Engineer could provide documents for each functional and non-functional requirement. The Engineer should use natural language for non-functional requirements and structured language for functional requirements. The functional requirements are more for developer’s eyes and to use. The non-functional requirements are what user wants and what they except to get out of the software being developed. The engineer would also have to make sure that the non-functional requirements don’t conflict with the functional requirements

Question four

Using your knowledge of how an ATM is used, develop a set of use cases that could serve as a basis for understanding the requirements for an ATM system.

Solution

Ø  The user inserts card into the reader. The ATM asks for PIN. User enters PIN correctly. The ATM displays user’s bank information and user withdraws money. The ATM dispenses the money

Ø  The user inserts card into the reader. The card cannot be read. The ATM displays the error and ejects the card

Ø  The user inserts card into the reader. The ATM asks for PIN. User enters PIN incorrectly 5 times. The ATM alerts the bank of a possible stolen card