Chapter 12 - Software Development

Question 1

Program development lifecycle

Answer 1

Process of developing a program set out in 5 stages: analysis, design, coding, testing, maintenance

Question 2

Analysis

Answer 2

Part of program development lifecycle
Process of investigation, leading to the specification of what a program is required to do. Involves creating a requirements specification which clearly sets out and defines the problem being solved

Question 3

Design

Answer 3

Part of program development lifecycle
Uses the program specification from the analysis stage to show how the program should be developed. Can be done through structure charts, state-transition diagrams and pseudocode

Question 4

Coding

Answer 4

Part of program development lifecycle
The writing of the program or suite of programs

Question 5

Testing

Answer 5

Part of program development lifecycle
Testing of a program to make sure it works under all conditions

Question 6

Maintenance

Answer 6

Part of program development lifecycle
Process of making sure that the program continues to work during use and throughout its life. Involves dealing with arising problems, correcting errors, improving functionality or adapting the program to meet new requirements

Question 7

Waterfall model

Answer 7

A linear sequential program development cycle, in which each stage is completed before the next is begun. Most suitable for smaller projects with a short timescale

Question 8

Iterative model

Answer 8

Type of program development cycle in which a simple subset of the requirements is developed, then expanded or enhanced, with the development cycle being repeated until the full system has been developed. Most suitable for projects for which the major requirements are known but some details are likely to evolve or change over time

Question 9

RAD

Answer 9

Rapid Application Development
Type of program development cycle in which different parts of the requirements are developed in parallel, using prototyping to provide early user involvement in testing. Most suitable for complicated projects that need developing in a short timeframe,e to meet the evolving needs of a business

Question 10

Structure chart

Answer 10

Modelling tool used to decompose a problem into sub-tasks. Shows hierarchy/structure of the different modules and how they connect & interact with each other. Each module is represented by a box and the parameters passed to and from the modules are shown by arrows. Each level of the chart is a refinement of the level above. Show selection.

Question 11

FSM

Answer 11

Finite State Machine
Mathematical model of a machine than can be in one state of a fixed set of possible states. One state is changed to another by an external input (transition). Behaviour of an FSM is shown using a state-transition diagram

Question 12

State-transition diagram

Answer 12

Diagram showing the behaviour of a finite state machine

Question 13

State-transition table

Answer 13

Table showing every state of a finite state machine, each possible input and the state after the input

Question 14

Trace table

Answer 14

Table showing the process of dry-running a program with columns showing the values of each variable as it changes

Question 15

Run-time error

Answer 15

An error found in a program when it is executed, the program may halt and unexpectedly go into an infinite loop and need to be stopped by brute force. If the program is being tested in an IDE then this type of error may be managed and a suitable error message produced

Eg. Zero error

Question 16

Test strategy

Answer 16

Overview of the testing required to meet the requirements specified for a particular program. Shows how and when the program is to be tested

Question 17

Test plan

Answer 17

Detailed list showing all the stages of testing and every test that will be performed for a particular program

Question 18

Dry run

Answer 18

Method of testing a program that involves working through a problem/module manually

Question 19

Walkthrough

Answer 19

Method of testing a program. Formal version of a dry-run using pre-defined test cases

Question 20

Normal test data

Answer 20

Test data that should be accepted by a program

Question 21

Abnormal test data

Answer 21

Test data that should be rejected by the program

Question 22

Extreme test data

Answer 22

Test data that is on the limit of that accepted by a program

Question 23

Boundary test data

Answer 23

Test data that is on the limit of that accepted by a program/data that is just outside the limit of that rejected by a program

Question 24

White-box testing

Answer 24

Method of testing a program that tests the structure and logic of every path through a program module

Question 25

Black-box testing

Answer 25

Method of testing a program that tests a module’s inputs and outputs

Question 26

Integration testing

Answer 26

Method of testing a program that tests combinations of program modules that work together

Question 27

Stub testing

Answer 27

Use of dummy modules for testing purposes, useful when not all the modules in integration testing have been written

Question 28

Alpha testing

Answer 28

Testing of a completed/nearly completed program in-house by the development team

Question 29

Acceptance testing

Answer 29

Testing of a completed program, to prove to the customer that it works as required

Question 30

Beta testing

Answer 30

Testing of a completed program by a small group of users before it is released

Question 31

Corrective maintenance

Answer 31

Correction of any errors that appear during use

Question 32

Perfective maintenance

Answer 32

Process of making improvements to the performance of a program

Question 33

Adaptive maintenance

Answer 33

Alteration of a program to perform new tasks

Question 34

Stages in the program development lifecycle (5)

Answer 34

Analysis Design Coding Testing Maintenance

Question 35

Purpose of a program development lifecycle

Answer 35

Do develop a successful program that is going to be used by others to perform, a specific task or solve a given problem. The development needs to be well ordered and clearly documented

Question 36

Principles of the waterfall model (3)

Answer 36

Linear, each stage is completed before the next is begun Well documented as full documentation is completed at every stage Low customer involvement, only at the start and end of the process

Question 37

Benefits of the waterfall model (4)

Answer 37

Easy to manage, understand and use Stages do not overlap and are completed one at a time Each stage has specific deliverables Works well for smaller programs where requirements are known and understood

Question 38

Drawbacks of the waterfall model (4)

Answer 38

Difficult to change the requirements at a later stage Not suitable for programs where the requirements could be subject to change Working program is produced late in the lifecycle Not suitable for long, complex projects

Question 39

Principles of the iterative model (3)

Answer 39

Incremental development as the program development lifecycle is repeated Working programs are produced for part of the system at every iteration High customer involvement, part of the system can be shown after every iteration

Question 40

Benefits of the iterative model (4)

Answer 40

Some working programs developed quickly at an early stage in the lifecycle Easier to test and debug smaller programs More flexible as easier to alter requirements Customers involved at each iteration so no surprises when final system delivered

Question 41

Drawbacks of iterative model (3)

Answer 41

Whole system to be defined at start, so it can be broken down to pieces + developed at each iteration Needs good planning overall and for every stage Not suitable for short simple projects

Question 42

Principles of RAD development (3)

Answer 42

Minimal planning Reuses previously written code and automated code generation where possible High customer involvement, customers can use the prototypes during development

Question 43

Benefits of RAD (4)

Answer 43

Reduced overall development time Rapid frequent customer feedback informs the development Very flexible as requirements evolve from feedback during development Parts of system are developed side by side so modification is easier as each part must work independently m

Question 44

Drawbacks of RAD (3)

Answer 44

System under development needs to be modular Needs strong teams of skilled developers Not suitable for short, simple projects

Question 45

RAD diagram

Answer 45

Question 46

Iterative model diagram

Answer 46

Question 47

Waterfall model diagram

Answer 47

Question 48

Construction of state-transition diagrams (6)

Answer 48

States are represented as nodes (circles) Transitions are represented as interconnecting arrows Events are represented as labels on arrows Conditions can be specified in square brackets after the event label The initial state is indicated by an arrow with a black dot A stopped state in indicated by a double circle

Question 49

Types of test data (4)

Answer 49

Normal test data Abnormal test data Extreme test data Boundary test data

Question 50

Types of testing during development of a program (3)

Answer 50

White box testing Black box testing Integration

Question 51

Types of testing after completing the program (3)

Answer 51

Alpha testing Beta testing Acceptance testing

Question 52

Program maintenance categories (3)

Answer 52

Corrective maintenance Perfective maintenance Adaptive maintenance