The document provides information about software development lifecycles and project management. It discusses requirements gathering, domain modeling, coding, testing at various stages, deployment, and managing projects using agile methodologies like Scrum. Specifically, it outlines the development lifecycle from requirements to deployment, emphasizing good management processes, developer skills, and tools are needed to build quality software. It also describes how Scrum is used to manage projects through prioritized backlogs, sprints, daily standups, and retrospectives to continuously improve.

1. Welcome to the Brixton Library
Technology Initiative
(Coding for Adults)
ZCDixon@lambeth.gov.uk
BasilBibi@hotmail.com
January 30th 2016
Week 3 – Software Development

2. Software Development
• The development lifecycle.
• How projects are managed.

3. Development Lifecycle
• How software is built.
Building good quality software is very hard.
Depends on good management process,
developer skills and tooling.
• Management process – clear objectives, realistic estimates
and robust quality assurance.

4. Development Lifecycle - Requirements
• Requirements are formal, mostly technology agnostic
statements about what the system should do.
• They are gathered and documented by a business
analyst (BA) sometimes called a domain expert /
domain specialist.
• Documented as a “Use Cases” or “Stories”– one per
business function.
“An account holder should be able to withdraw funds from their
account.”
“A customer should be able to browse stock.”

5. Development Lifecycle – Domain Modelling
• The “domain” is a description of all the business
‘things’ in the system and how they are related.
• Analysts look at the Use Cases and pick out the
nouns to model the domain.
“An Account Holder should be able to withdraw
money from their account.”
• These are called “Entities” and usually go on to
become tables in a database and Objects in object
oriented design.

6. Development Lifecycle – From Use Case to Code
• Developers work on Use Cases and produce code or
working components.
• Use cases are elaborated to refine details and
produce sub tasks.
• Developers use IDEs, code repositories, automated
build management tools to complete their tasks.
• Testing.

7. Development Lifecycle – Testing
• How do you prove that everything works correctly?
• Break the problem down into small chunks and build up.
• Unit test - verifies that a single function works.
• Unit tests - confirm that a module or class works.
• Integration tests - groups of dependent modules or classes.
• System tests - makes sure that the whole system connects to
with systems and works correctly.
• User Acceptance Testing (UAT) - the users check that the use
cases are satisfied and ‘sign off’ on them.
• Performance tests - make sure the system hasn’t slowed down
with each release.
• Regression tests - Test that the system has not ‘regressed’ i.e.
new bugs that were hidden may arise in unexpected places.
• Smoke tests - make sure that when the system goes live
everything works as expected.

8. Development Lifecycle – Deployment
• The code is put into “Production” and monitored.
• When bugs surface they are either dealt with
immediately or are prioritised fixed later.
• All systems have bugs.

9. Development Lifecycle – Deployment
• All systems have bugs some not in code but in process.
• Allegedly caused by a corrupt database backup when
the main database failed.
• All transactions had to be replayed – took a long time to
fix and under tremendous pressure – image that.
• Cost to reputation as well as fines.

10. How Projects Are Managed - Agile
• Work is managed and planned with milestones and releases.
• This is done using various methodologies.
• There have been many methodologies over the decades.
• Most failed because they tried to plan too much ahead of
time.
• Waterfall – plan everything in minute detail up front.
• Very costly up front with nothing to show but paperwork.
• Hard to change once a commitment is made.
• Better to have a rough idea and refine it as you go along with
frequent user intervention and involvement.
• “Agile” is currently a very popular PM methodology – a
variant for software development is called “scrum”
• Old joke - What’s the difference between a Terrorist and a
Methodologist?
• You can negotiate with a terrorist ;)

11. How Projects Are Managed

12. How Projects Are Managed – Scrum
• All of the Stories are put into a Backlog.
• Stakeholder decides priority of stories.
• Developers analyse the story and estimate how long it will
take to complete using Story Points.
• Story Points are a measure of complexity based on the
Fibonacci series.
• A story point might be worth 2.5 days.
• Estimated stories are ready for development. These are then
organised into “sprints”.
• Sprint is usually a 2 week cycle with a demo of working code
at the end.
• The team meet every morning at a stand up to discuss
progress and blockers.
• Other team members and/or the scrum master help out
with blockers.
• Sprints and deliverables are organised into releases.

13. How Projects Are Managed– Sprint
• Prior to a sprint starting the developers do their
estimation.
• The sprint is punctuated by daily stand ups.
• The sprint concludes with a demo.
• Any work not completed carries over to the next sprint.
• The sprint itself is analysed in a sprint retrospective
which asks:
• What did we do well?
• How can we improve?
• How accurate is our estimation and why?
• How many story points did we complete in the sprint?
• This gives a measure of “velocity”.