9.2.1 Defining and understanding

Question 1

What are some ways that the needs of the client can be determined?

Answer 1

Surveys, observation, interviews, business analysis.

Question 2

What is the role of a systems analyst?

Answer 2

To analyse existing systems of a business or organisation, determine requirements and design new information systems.

Question 3

What is a cost-benefit analysis?

Answer 3

A systematic approach to estimating the strengths and weaknesses of alternatives. Can be used to consider whether it is worth pursuing a proposed solution.

Question 4

Why is a cost-benefit analysis important for software developers?

Answer 4

Cost benefit analysis is an assessment of the strengths and weaknesses of a proposed solution and so is useful for developers to check whether it is feasible to pursue this solution and so can save both time and effort.

Question 5

What is a feasibility study?

Answer 5

A systematic assessment of the practicality of a proposed solution.

Operational feasibility includes consideration of the people involved in the functioning system and their needs such as training and day to day use.

Technical feasibility includes aspects such as hardware, software and network requirements.

Schedule feasibility considers whether the solution can be implemented in a timely manner.

Other feasibility considerations include legal and budgetary concerns.

Question 6

Why would systems modelling tools be used in the defining and understanding stage of software development?

Answer 6

To model the operation of the existing system, thus developing a thorough understanding of the inputs, outputs and processes involved in the system.

Question 7

What are the essential features of a context diagram?

Answer 7

Represents a system as a single process with inputs and output and their sources.

Question 8

What are the symbols used in context diagrams?

Answer 8

Question 9

What are the essential features of a data flow diagram?

Answer 9

Represents the entire system as a number of processes with sources/destinations of inputs/output.

Question 10

What are the symbols used in data flow diagrams?

Answer 10

Question 11

What are the essential features of a systems flowchart?

Answer 11

Describes the logic and flow of data through a system including the media used.

Question 12

What are the symbols used in a systems flowchart?

Answer 12

Question 13

What are the essential features of a structure chart?

Answer 13

Shows separate modules/subroutines comprising the system and their relationship to each other.

A structure chart can be directly translated into pseudocode, showing subroutines with required parameters and return values, decisions and loops.

Question 14

What are the symbols used in structure charts?

Answer 14

Question 15

Which form of system documentation is a refinement of another type?

Answer 15

A data flow diagram is a refinement of a context diagram.

The data flow diagram expands the single process of the context diagram to show a number of sub-processes and the data flow between them.

Question 16

What are the essential features of an IPO diagram?

Answer 16

An Input Process Output diagram is a table that describes the inputs to a process, the steps involved in the process and the subsequent output.

It can be used to describe the operation of a larger system, or a specific subroutine.

Question 17

What is a data dictionary?

Answer 17

A table that details of the purpose, data type and format of variables used in a solution.

Question 18

What is a storyboard?

Answer 18

Details the movement between screens of a user interface.

Question 19

What are design specifications?

Answer 19

A set of documentation used to develop a software solution, including the requirements of the system and the functional components of the design to meet the requirements. It outlines the overall processes that work together to produce the output that meets the requirements.

Question 20

What should design specifications from the users’ perspective include?

Answer 20

1. Interface design
2. Social and ethical issues
3. Users environment and computer configuration

Question 21

What should design specifications from the developer’s perspective include?

Answer 21

1. Data types
2. Data structures
3. Algorithms

Question 22

What is quality assurance?

Answer 22

An ongoing process to ensure the quality of software.

Elements of quality may include efficiency, integrity, reliability, usability, accuracy, maintainability, testability.

Question 23

What are functionality requirements?

Answer 23

They are requirements that state the features, properties or behaviours a system must have to achieve its purpose.

Functionality requirements are verifiable, in that they are specific and measurable.

Question 24

What are performance requirements?

Answer 24

Requirements that refer to how well the software achieves its functions under certain conditions, such as the software’s speed of response, execution time and storage capacity.

Question 25

What are compatibility requirements?

Answer 25

Requirements that refer to how the software works in different environments, such as different devices, screen sizes and operating systems.

Question 26

What do the “boundaries of the problem” refer to and why are they important to consider?

Answer 26

The limits of the functionality, performance and compatibility of the software. They should be clearly set out so that the client understands precisely what the software will do and what it will not do.