Informatics 121 Software Design I Lecture 13 Andr

Today’s Lecture n Design rationale n Design histories n In-class design exercise n No

A Simple Question n Why is a given design as it is? September 21,

A Difficult Answer n Any design involves 100 s if not 1000 s of

Knowing Why Is A Crucial Need n Helps explain particular features to the customer

Sketchbooks September 21, 2021 – 11: 43: 05 © 2009 University of California, Irvine

Sketchbooks September 21, 2021 – 11: 43: 06 © 2009 University of California, Irvine

Sketchbooks September 21, 2021 – 11: 43: 07 © 2009 University of California, Irvine

Software Sketchbooks n If they exist, they tend to be text, text, … n

Design Rationale n “Design rationale is focused on capturing a historical record of the

Design Rationale n Descriptive – retroactive – aims to communicate a design’s intent n

IBIS September 21, 2021 – 11: 43: 08 © 2009 University of California, Irvine

g. IBIS September 21, 2021 – 11: 43: 08 © 2009 University of California,

Modern Variant September 21, 2021 – 11: 43: 09 © 2009 University of California,

SAAMPlayer September 21, 2021 – 11: 43: 09 © 2009 University of California, Irvine

Design Histories n Expand on design rationale by capturing design processes as they occur

ADDSS September 21, 2021 – 11: 43: 10 © 2009 University of California, Irvine

Alex’ Homegrown September 21, 2021 – 11: 43: 12 © 2009 University of California,

Automation? September 21, 2021 – 11: 43: 12 © 2009 University of California, Irvine

Automation? September 21, 2021 – 11: 43: 13 © 2009 University of California, Irvine

In-Class Design Exercise n Collectively, using the tablets and Calico, design a history representation

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Informatics 121 Software Design I Lecture 13 André van der Hoek & Alex Baker Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited. September 21, 2021 – 11: 43: 04 © 2009 University of California, Irvine – André van der Hoek 1

Today’s Lecture n Design rationale n Design histories n In-class design exercise n No assignment n Don’t mind the guy in the back with the video camera September 21, 2021 – 11: 43: 04 © 2009 University of California, Irvine – André van der Hoek 2

A Difficult Answer n Any design involves 100 s if not 1000 s of decisions that are tough to all remember n Worse yet, any design involves 100 s if not 1000 s of discussions, considerations of alternatives, and reasons why certain choices are made, which are even tougher to all remember September 21, 2021 – 11: 43: 04 © 2009 University of California, Irvine – André van der Hoek 4

Knowing Why Is A Crucial Need n Helps explain particular features to the customer n Helps assist with coding n Helps build a shared understanding of the design among a team of designers n Helps guide maintenance and other design changes – evolution – roadblocks n Helps reflect on one’s own design practices September 21, 2021 – 11: 43: 04 © 2009 University of California, Irvine – André van der Hoek 5

Software Sketchbooks n If they exist, they tend to be text, text, … n Maybe an architecture diagram – but with more text! n Maybe UML – but with more text! n … September 21, 2021 – 11: 43: 07 © 2009 University of California, Irvine – André van der Hoek 9

Design Rationale n “Design rationale is focused on capturing a historical record of the analysis that led to the choice of a particular artifact or feature in question, and in the most general sense is an explanation of why something is designed the way it is” n “Design rationale involves explicit capture of the design decisions that shaped a particular software system, or ‘knowwhy’ knowledge” September 21, 2021 – 11: 43: 07 © 2009 University of California, Irvine – André van der Hoek 10

Design Rationale n Descriptive – retroactive – aims to communicate a design’s intent n Prescriptive – in-the-moment – aims to improve the design process September 21, 2021 – 11: 43: 07 © 2009 University of California, Irvine – André van der Hoek 11

Design Histories n Expand on design rationale by capturing design processes as they occur over time, as most design does not take place in a single meeting n More focused on description than prescription to date September 21, 2021 – 11: 43: 10 © 2009 University of California, Irvine – André van der Hoek 16

In-Class Design Exercise n Collectively, using the tablets and Calico, design a history representation that you will use for the next assignment n André will lead the discussion using his tablet, as projected on the other screens n Use your tablets to support your verbal contributions, annotate our design in progress, develop another idea in parallel, etc. September 21, 2021 – 11: 43: 13 © 2009 University of California, Irvine – André van der Hoek 21