1.2.3 Software Development

Question 1

what is the software development lifecycle?

Answer 1

the distinct phases which programmers go through when developing a solution for a computer system

Question 2

what is a software development methodology?

Answer 2

the arrangement and how programmers move from one phase to another in the software development lifecycle

Question 3

what are the stages of the SDLC?

Answer 3

• feasibility
• requirements
• analysis and design
• implementation
• testing
• deployment
• evaluation
• maintenance

Question 4

what are the 5 methodologies?

Answer 4

waterfall
rapid application development
sprial
agile
extreme programming

Question 5

what are the features of the waterfall lifecycle?

Answer 5

• each phase has a well defined start and end point with identifiable deliverables
• once you end one phase, you never really return to it and move onto the next one

Question 6

what are the features of rapid application development (RAD)?

Answer 6

• produces successive prototypes of the software until the final version is produced and approved
• following approval of the feasibility of the program, increasingly refined prototypes are made wit reduced functionality
• each prototype is designed, coded, tested and evaluated with the user

Question 7

what are the four main quadrants of the spiral methodology?

Answer 7

• determine objectives
• identify and resolve risks
• development and test
• plan for next iteration

Question 7

what are the features of the spiral model?

Answer 7

• risk driven
• provides a guide for the team where the decisions on the software development methodology are made based on the risks identified

Question 7

what is agile development?

Answer 7

a group of methodologies which focus on the idea that requirements will shift and change during development and this can only be dealt with in an iterative way.

Question 8

what are sprints in agile methodologies?

Answer 8

short, time boxed periods when a team has focused goals to complete a set amount of work
- should only be a bite sized piece of focused work

Question 9

what is extreme programming?

Answer 9

a framework for software development

Question 9

what is the aim of extreme programming?

Answer 9

produce high quality code and promote developers’ quality of life by adopting a set of common practices

Question 9

what are the values of extreme programming?

Answer 9

• simplicity
• communication
• feedback
• courage
• respect

Question 10

what are the 5 core practices of extreme programming which are generally thought to boost overall quality of any solution to almost any project?

Answer 10

• collective code ownership
• continuous integration
• code standards
• refactoring
• paired programming

Question 11

what are some benefits of the waterfall methodology?

Answer 11

• simplicity = easy to manage
• everyone knows responsibilities at each stage
• clear deliverables
• easy to see if project running to schedule

Question 12

what are the drawbacks of the waterfall methodology?

Answer 12

• carries a lot of risk
• user doesn’t get to see product for the first time until the end is near
• misunderstanding requirements can lead to the problems not easy to fix
• requirements must be well understood so not suitable for complex projects

Question 13

when would the waterfall model be used?

Answer 13

ease of management means it is suitable for large scale development projects
- have to be well understood and carry little risk

Question 14

what are the advantages of RAD?

Answer 14

• requirements don’t need to be clear from the start
• focus groups involving user can be used to gather info without formal documents at first
• continuous feedback from client means solution is likely to have excellent usability

Question 15

what are the disadvantages of RAD?

Answer 15

• focuses on usability rather than how product works - got good where efficiency is important
• regular contact with client must be kept at all times
• scales poorly for large projects with big teams

Question 16

when is RAD good to use?

Answer 16

for projects where initial requirements are not fully understood and iterative nature prevents development being side-tracked

Question 17

what are the advantages of the spiral model?

Answer 17

• risk management centred
• good for high risk projects

Question 18

what are the disadvantages of the spiral model?

Answer 18

• expensive as risk management is a highly specialised skill
• if risk analysis done badly, project suffers

Question 19

when is the spiral model good?

Answer 19

• large scale problems that involve high degrees of risk

Question 20

what are the advantages of agile and extreme programming methodologies?

Answer 20

• emphasises programming so end code is high quality
• core principles and processes promote respect and collaboration which is likely to lead to a productive team

Question 21

what are the disadvantages of agile and extreme programming methodologies?

Answer 21

- requires a team of programmers working closely which is an issue if team is far apart - client must commit to a full time representative working with the team - some processes are costly (eg. paired programming)

Question 22

when is agile and extreme programming good?

Answer 22

when the emphasis on the project is on the quality of the finished code

Question 23

what is an algorithm?

Answer 23

a sequence of steps designed to perform a task

Question 24

how can algorithms be written?

Answer 24

pseudocode flowcharts high-level language

Question 25

what is pseudocode?

Answer 25

text based method of representing algorithms - like simplified programming code

Question 26

why is pseudocode good?

Answer 26

allows us to lay down logic without worrying about rules + syntax of a particular language

Question 27

how do you refine an algorithm?

Answer 27

- find areas which need modifying - change appropriate areas

Question 28

what are the 6 flowchart symbols?

Answer 28

- terminal - process - decision - input/output - subroutine - like

Question 29

why do programs need to be tested?

Answer 29

to make sure it works as intended

Question 30

what are the most common test strategies?

Answer 30

- black-box - white-box - alpha - beta

Question 31

what does black-box testing check?

Answer 31

if an input produces the expected output

Question 32

how is black-box testing done to test the inputs and outputs of a program?

Answer 32

choose appropriate test data that covers a range of situations

Question 33

what is white-box testing?

Answer 33

tests the algorithms in the code and makes sure all parts of the algorithms function as intended - checks efficiency

Question 34

when are alpha and beta testing done?

Answer 34

when software is nearly ready for release and can be tested as a complete solution

Question 35

when and with who does alpha testing occur?

Answer 35

occurs before beta limited to internal employees and their friends or family very early software with bugs and rough

Question 36

when and with who is beta testing done?

Answer 36

opened to a wider community through a public beta program - almost finished version

Question 37

what are the types of test data?

Answer 37

- no data - erroneous data - normal data - boundary data

Question 38

what is erroneous data?

Answer 38

data that should be rejected by the program

Question 39

what is normal data?

Answer 39

data that should be accepted without errors

Question 40

what is boundary or extreme data?

Answer 40

data of the correct type that is on either edge of the accepted validation limits

Question 41

what is tracing execution?

Answer 41

examining a printed extract of program code and running through the program

Question 42

how do you perform tracing execution?

Answer 42

take each line at a time and write out the current state of each variables in a trace table noting the outputs.

Question 43

what is the structure of a trace table?

Answer 43

- each variable has its own column - a new row should be added if the state of a variable changes

Question 44

what does regular feedback with the user allow?

Answer 44

- keeps project focused - makes sure you develop the actual system they need - provides opportunities for discussion - makes the user feel part of the finished solution