CSC 509 Software Engineering II

1. CSC 509Software Engineering II Winter Quarter, 2005 Clark S. Turner

2. Administration • Instructor • Clark S. Turner • Required Books • Petroski, “To Engineer is Human” (read last term) • Winograd, “Bringing Design to Software” (read cover to cover) • Simon, “The Sciences of the Artificial” (you skimmed last term? read cover to cover) • Office: 14-211 • phone (805) 756 6133 • Office Hours: • Tuesday, 12:10 - 3 pm • Thursday 2:10 - 4 pm • Prerequisites • 205, 508, permission of instructor, graduate standing • Course website at: • www.csc.calpoly.edu/~csturner

3. Basic Course Requirements • Attendance and participation • Presentations (you are expected to volunteer) to class • Reporter duty to the class (abstract class progress each week) • Personal journal recommended • Near publishable quality research paper • 20 - 40 pages • proper use of sources to develop arguments • significant bibliography • topic in software engineering design (broadly interpreted) • chosen, proposed by you, may be continuation of 508 work • focus on design aspects • double dipping is fine with me • collaboration is fine with me, but clear credit must be given to collaborators

4. The Basic Definition of our Work (again) • Software Engineering is... • the study of software process, software development principles, methods and tools • requirements elicitation and analysis • requirements and design notations • implementation strategies • testing methods • maintenance techniques • management strategies • the production of quality software, delivered on-time, within budget, and satisfying users’ needs

5. The problem and the response... • Software is typically • late • over budget • faulty • hence... the “software crisis” • go see the “Chaos Report” referenced on my website! • Software Engineering • software production should use established engineering principles • history: coined in 1967 and endorsed by a NATO conference in 1968

6. What type of software? • Small single-developer projects can typically get by without Software Engineering • typically no deadlines, small budget (freeware), not safety-critical • Software Engineering is required for • large projects (100,000 lines of code and up) • multiple subsystems • teams of developers (often geographically dispersed) • safety-critical systems (software that can kill people...)

7. What is Engineering? • Engineering is • sequence of well-defined, precisely-stated, sound steps, which follow method or apply technique based on some combination of • theoretical results derived from a formal model • empirical adjustments for un-modeled phenomenon • rules of thumb based on experience • This definition is independent of purpose ... • “engineering” can be applied to many disciplines • however, does software have the formal models, rules of thumb...? • Are software “engineers” employees or professionals? • are we independent in our employ? • do we have obligations to society? • go look at the Software Engineering Code of Ethics (ref on my website)

8. Software Engineers require ... • a broad range of skills • Mathematics • Computer Science • Economics • Management • Psychology • applied to all phases of software production • are we indeed supposed to be “general engineers?” • Recall Jackson’s diatribes

9. Requirements and Design Aspects • User needs and perceptions are difficult (impossible?) to assess • functionality isn’t enough • Requirements specification is a contract with the customer • Requirements must provide a definitive basis for testing • Requirements is about the domain of the problem • Design suggests a solution in the software domain Requirements addresses “what?” Design addresses “how?” Or is “Design” on the other side of Jackson’s boundary?

10. Sample Software Qualities • Correctness • Reliability • Robustness • Performance • Usability • Testability • What do these terms mean? • what are the relationships between these qualities? • how can we “design” for such qualities?

11. Uniqueness of Software • What are we dealing with? • The stuff doesn’t “wear out” (but does exhibit a bathtub curve …) • The stuff has no “tolerance” - it is binary • The stuff weighs nothing, and you can’t really “see” it. • It is very plastic, we can always “change” it in place • try that with your automobile! • Why don’t other engineering principles apply? • For example, statistical reliability methods? • No mean value theorem applies • No accurate user profile or operational distribution • So, when we test, what do we find out about software? • Can’t tell for sure if our software is good or not.

12. Definitions! • Research (read the shaw paper linked on website!) • Process • go read Osterweil’s “Software Processes are Software Too” (link on my website) • Tools • Methods • Design • Function • distinguish “feature”

13. Design - the topic of the course • Are we “designers?” • give a few definitions • what is a “great designer” (Brooks?) • Is “design” about • meeting the customer’s specifications (contract) • solving the user’s problem • exactly who is the “user” and who is interested?

14. Read for next time • Read • Ch 5 of Simon’s book regarding “the science of design” • Winograd (sections 1 - 3) • Assign all Winograd, some Simon • Need volunteers to present • How do these pieces stack up as research and contributions to knowledge? • Detail: • facts of the situation, problem statement • arguments about possible solutions • author’s analysis of arguments and author’s solutions (or answers) • your analysis of author’s work

15. Class Reporters • Need 2 volunteers each week • each take notes on all work presented that week • meet after the week’s classes: • discuss important and weak points • make list of open questions discussed • make list of questions that arise from the whole week of discussions • make list of questions that actually were answered • create a 10 minute presentation for start of following week to analyze the previous week’s work in class • Not a mere summary or abstract • Needs to contain real thought, insights and questions raised • Deliverable: present a written report (can be paper outline of slide presentation) with names, dates and relevant information to me • volunteers chosen at first class