1. Informatics 122 Software Design II
Lecture 1 André van der Hoek
Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited.
January 1, 2019 – 12:00:02
(c) 2006 University of California, Irvine – André van der Hoek

2. © 2006 University of California, Irvine – André van der Hoek
Today’s Lecture
Logistics
Review
Preview
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

3. © 2006 University of California, Irvine – André van der Hoek
Logistics
No TA
No required book
Grading: class participation is an important part
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

4. Review: Alternative Design Exercises
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

5. Review: The Term “Design”
“Design” may refer to an activity
“When I design, I always use a whiteboard first”
We will use: design activity
“Design” may refer to a product
“My design is super cool, I know it will work”
We will use: design product
“Design” may refer to a field
“Software design is complex”
We will use: design field
Should we include this? We don’t quite stick to it…
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

6. Review: Design Diamond
Domain of Materials
Domain of Use
Knowledge
Representation
Ideas
Activity
concern
manipulates
informs
Goal
captures
enhances
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

7. Review: Seven Fundamental Dimensions
Goal
Objectives that frame a design problem
Ideas
Individual understanding of a design problem and its solution
Representation
Expression of an understanding of a design problem and its solution
Activity
Acts that contribute to the crafting of a design solution to a design problem
Knowledge
Individual wisdom about design problems and their solutions
Domain of Use
Collective wisdom about design problems and their solutions
Domain of Materials
Collective wisdom about the resources available to implement design solutions
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

8. Review: Informatics 121 (and thus 122!) View
System design
describes what the software system should do
focus towards addressing Goal and Domain of Use
“How do we fundamentally approach the problem?”
typically represents an intermediate “design in progress”
architecture design can be part of system design
Implementation design
describes what the implementer should do
focus towards addressing Domain of Materials
“How do we make the approach reality?”
typically represents a final “completed design”
module design can be part of implementation design
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

9. © 2006 University of California, Irvine – André van der Hoek
Review: Definitions
A system design captures the essence of the solution
customers
system designers themselves
implementation designers
testers …
An implementation design captures the full solution
system designers
implementation designers themselves
programmers
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

10. © 2006 University of California, Irvine – André van der Hoek
Review: System Design
Booch …
pi calculus
informal drawing
UML
System Design
pseudo code
architecture
text
code
data flow diagrams
Statecharts
JSD
any and all as needed
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

11. Review: Goals of Implementation Design
Provide a shared plan to follow
Consistency
Ensure the plan meets its recipients’ needs
Helpfulness
Ensure the solution is appropriate
Effectiveness
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

12. Review: Design Concerns
A typical design problem consists of many different concerns that must all be addressed by a design solution
Some of these concerns are more important and/or have more impact than others
“I want my e-commerce site to have a recognizable logo” versus “My e-commerce site must scale to 1 million hits per minute”
Sometimes, the importance and/or impact of a concern is not obvious (the devil is in the details)
“I want my payroll software to properly handle the exchange rate”
As a designer, you need to find the concerns that are most important and have most impact
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

13. From Informatics 121 to Informatics 122
To date, much of our focus has been on system design
creative thinking
learning to rely on colleagues
incomplete specifications
no implementation
Now, it is time to turn our attention to implementation design
nuts and bolts (but still some creative thinking)
specifying for colleagues (but still relaying some on colleagues)
complete specifications
implementation
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

14. © 2006 University of California, Irvine – André van der Hoek
Sample of Topics
Good design/bad design
Design patterns
Design recovery
Components
Large-scale design …
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

15. © 2006 University of California, Irvine – André van der Hoek
Sample of Topics
Good design/bad design
Design patterns
Design recovery
Components
Large-scale design …
…and of course…
Actual design exercises
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek

16. © 2006 University of California, Irvine – André van der Hoek
First Assignment
Read “Taste for Makers” by Paul Graham
if you want to read more, of course you can read more
available on the class web site
Read “Case Study: A Computer Science Perspective on Bridge Design” by Alfred Spector and David Gifford
Provide a 1 page summary with what you consider are the major lessons to learn from these texts and how these lessons relate to the topic of software design
Wednesday
January 1, 2019 – 12:00:02
© 2006 University of California, Irvine – André van der Hoek