1 - Intro

Question 1

Big problem with modern software?

Answer 1

Needs to be updated regularly to fix bugs and issues

Question 2

Bugs in past for software development

Answer 2

Relatively rare cause of failure

Question 3

Most common failure?

Answer 3

Building wrong system

Difficult to find customer requirements, more difficult as system becomes larger

Question 4

Cost of developing software

Answer 4

Cheap to duplicate

Expensive to design

Question 5

Where is most of the software work

Answer 5

Design, not manufacturing

Labor intensive and craft activity

Question 6

Automating software creation

Answer 6

Very difficult to automate design activity

Can create better tools for designers

Question 7

Cost of developing software vs copies sold

Answer 7

Largely indepedent, it is a high risk activity

Question 8

Software complexity

Answer 8

Can be very complex

Difficult to understand exactly how it works

Relatively easy to modify

Relatively easy to create software that appears to work

Hard to show it does everything it should do

Question 9

Main way of testing?

Answer 9

Using different input values

There are so many, impossible to test all

Question 10

Estimating how much work to create software

Answer 10

Very difficult to price in advance

First 90% takes 90% of the time, second 90% takes remaining 90%

Question 11

Quoting price for software

Answer 11

Quote lowest price and increase later when you know more about work involved

Question 12

Wear and tear of software

Answer 12

Does not wear out

Question 13

Finding bugs after release

Answer 13

User experience

Continued testing

Question 14

In-direct changes to operation of software

Answer 14

Changes to OS and supporting programs

Question 15

Making corrections to released software

Answer 15

Consistency of design deteriorates

New defects are introduced

Question 16

Software after a length of time

Answer 16

Will eventually stop working due to changes in OS, runtimes etc

Question 17

Making small pieces of software

Answer 17

Possible to do this with almost any approach

Question 18

Making larger software

Answer 18

Most approaches of software dev don’t scale up

Reaches and stays “almost working” state

Becomes difficult to understand and change

Question 19

Software development market

Answer 19

Very competitive

Question 20

Getting new software to market first

Answer 20

Will get most of the sales

Question 21

Latecomer bringing the “best” software to market

Answer 21

Often won’t make as much money as those who done it first

Question 22

Quality of software to sell it

Answer 22

Just has to be “good enough”

“best” is enemy of “good enough”

Question 23

After selling software

Answer 23

Many bugs will still have to be fixed after product is sold

Patch cycle

Question 24

Types of software - Custom

Answer 24

Developed to solve specific problem

Air traffic control

Question 25

Types of software - Generic

Answer 25

Developed to solve many different problems Word processor

Question 26

Types of software - Embedded

Answer 26

Runs hardware devices DVD players Cars

Question 27

Aspects of Software Engineering

Answer 27

Solving customers' problems Systematic development Large high quality systems Within cost, time and other constraints

Question 28

Soft Eng - Solving Customers' Problems

Answer 28

Customer decides what they need Avoid unnecessary features, find out what customer really wants/needs (they often dont know exactly) Can be more cost effective to buy existing software, or to decline project/customer and not build the software Human activity, interaction with non-technical people

Question 29

Soft Eng - Systematic Development

Answer 29

Use well understood techniques - OOP, UML Use disciplined approach Continue developing software after its delivered Use precise language for non-technical people, natural language is often ambiguous

Question 30

Soft Eng - Large High Quality System

Answer 30

Single skilled coder can keep track of tens of thousands of LOC Many systems larger than this, need a team Need a consistent approach to documentation and coding style

Question 31

Soft Eng - Cost, Time and Other Constraints

Answer 31

Need to earn enough to pay wages and more Not worth doing if it wont earn enough If someone is cheaper and faster, they will get the money Create budget and plan, monitor if you are sticking to them Set and meet milestones Check with customer often

Question 32

Stakeholders

Answer 32

``` Users Customers - Paying for software - Often employ users Developers Managers - Keep customer satisfied ```

Question 33

External Software Quality

Answer 33

Usability - Learnability, efficiency of use, error handling Efficiency CPU, memory, disk space, network bandwidth Reliablity Maintainability Reusability Cant be good at all, make tradeoffs

Question 34

Internal Software Quality

Answer 34

Not noticed by customer Effects maintainability Commenting code - Important as programs get bigger - Could be you trying to understand your own code after a year Complexity of code - Use OOP to counter - Make individual code segments simple

Question 35

Types of projects - Greenfield

Answer 35

Start from scratch Not constrained by previous decisions Dont have to understand code written by otehrs Rare in industry

Question 36

Types of projects - Evolutionary

Answer 36

Fix defects Add features Adapt to changing environments

Question 37

Building a framework

Answer 37

Software reuse across projects saves money Most projects are different, specific to customers Projects often have common components Create a library of common components of framework - long term pay off Internal project Money comes from customer projects