Software Art Thou: Real Software Engineering
A summary of the lecture by Glenn Vanderburg currently VP Engineering at First.io
https://youtu.be/RhdlBHHimeM
Zendesk published a Youtube in January 2018 in which Glenn Vanderburg talks about the nature of Software Engineering and offers some insightful comments. Since many of his points are important to the research I am doing I am creating a summary of this Youtube to assist in citation. Parenthetic remarks are time m
Where SE went wrong and how to fix.
(0:27) Programmers: Stop Calling Yourselves Engineers, The Atlantic. Are SEs engineers?
Software Engineering: An Idea Whose Time Has Come and Gone?, Tom DeMarco, Computer Magazine, ACM? IEEE?
"Calling what we do 'engineering' doesn't make us engineers. It makes us liars, Dave (Pragmatic) Thomas, Extreme Programming mailing list at 2003
(2:04) Arguments against SE as engineering reduce to charge that it is fundamentally different from other engineering or that it is more artistic than engineering which essentially is the same argument.
The term Software Engineering can be traced to a NATO publication from a conference in Garmisch Germany in Oct 1968. And then Rome 1969.
He calls the 1969 the launch of Academic Software Engineering and was analytical, formal and aspirational toward engineering.
All academic software engineering (ASE) modeled process models of large scale engineering projects. Requ
Allister Colbert, was proj successful? how strictly to chosen process? PM differed from coders. Would you use this process again? (mostly no)
good people who cared were motivated to subvert process
in mid 90s, attempt to find new process, Agile
less iterative, experimental, less formal, correctness by testing, rapid adoption.
Now two views: software development should be more like engineering and software development is NOT like engineering.
Both ignore what engineering process really is.
Herbert Simon, The Sciences of the Artificial,
A Rational Model of Software , Parnass
(12:50) Glenn's view:
Software development already is engineering
it always was
the rational model (Parnass) is a caricature of engineering since no engineering is really done that ways and some look nothing like that
We don't need to become engineers but refine the software engineering process which does not have to adhere to the academic software engineering processes that were first suggested.
Remainder of talk:
the errors of ASE, what is engineering?, what is SE?, what's next?
(15:00)
The Errors of Analy\tical software engineering
Brian Randell, newcastle ed 1968
history of software engieering conference 1996
At that history of SE cibnference, he said:
"Unlike the first conference, at which it was fully accepted that the term softare engineering expressed a need rather than a reality, in Rome there was already a slighgt tendency to talk as if the subject already existed. And it became clear during the conference that the organizers had a hidden agenda, namely that of persuading NATO to fund the setting up of an Internal Software Engineering Institute. However things did not go according to their plan. The discussion sessions which were meant to provide evidence of strong and extensive supooret for this proposal were instead marked by considerable scepticism, and led one of the participants, Tom Simpson of IBM, to write a splendid short satire on 'Masterpiece Engineering'. IOt was little surprise to any of the participants in the Rome conference that no attempt was made to continue the NATO conference series, but the software engineering bandwagon began to roll as many people started to use the term to describe their work, to my mind often with very little justification. ... I made a particular point for many years of res\fusing to use the term or be associated with any even that used it." Brian Randell
Early dissents
Alan Perliss. in 1968
A softwae system can best be designed if the testing is interlaced with the designing instead of being used after the design. (TDD)
A simulation which matches the reqrements contains the cotrol which organizes the design of the system.
Througb successive repetititons of this process of interlaced testing and design the model ultimately becaomes the software system itself. ... in effect the testing and the replacement of simulations with modules that are deeper and more detailed goes on with the simulatin model cotrolling, as it were, the place and order in which these things are done.
Fred Brooks, The Design of Design
Winston Royce agreed that waterfall seems like it should make sense but then went on to criticize it in the same paper. (Managing the Development of Large Software Systems http://www-scf.usc.edu/~csci201/lectures/Lecture11/royce1970.pdf)
"John H. Van Vleck, Nobel-laureate physicist was Dean of Harvard's Division of Engineer and Applied Science when I was a graduate student there, in Aiken's lab. Van Vleck was very concerned that the practice of engineering e put on a firmer scientific basis. He led a vigorous shift of American engineering education away from design toward applied science. The pendulum swung too far; reaction set in; and the teaching of design has been contentious every since. I am grateful that three of my Harvard teachers never lost sight of the importance of design and taught it: Philippe E Le Corbeiller, Hary R Mimno, and Howard H Aiken, my adviser."
Preface to The Design of Design by Fred Brooks
(19:47)
Devalued the role of code.
What is needed is not classical mathematics, but mathematics. Systems should be built at levels and modules, which form a mathematical structure." Friedrich Bauer
[...] our basic tools are mathematical in nature. -Edsger Dijkstra
David Parnas 2007 oopsla, "In engineering...people design through documentation,", "Code cannot fill that role."
Academic software engineering emphasized correctness over cost.
(23:27)
graph of cost of error correction versus phase of project where error is found. But, Glenn says, emphasis on careful review of all artifacts at all stages increases costs throughout since more reviews, more quality control is needed. "The cure is worse than the disease." Low cost, high impact. Cost of long feedback loops.
(25:00) What is engineering anyway?
"Unlike the extensive analysis of the scientific method, little significant research to date has sought the philosophical foundations of engineering. Library shelves groan under the weight of books by the most scholarly, most respected people analyzing the human activity called science. No equivalent body of research treats the engineering method." -Billy Vaughn Koen
8 good books on engineering process
The sciences of the Artifiicial, Herbert A Simon
The Design of Design, Gordon L Glegg
Definition of the Engineering Method, Billy Vaughn Koen
To Engineer is Human, Henry Petroski
What Engineers Know and How They Know It, Walter G Vincenti
Engineering and the Minds's Eye, Eugene S Ferguson
The Existential Pleasures of Engineer , Samuel C Florman
The Design of Design, Fred Brooks
[Programming] is not some kind of engineering where all we have to do is put something in one end and turn the crank." -Bruce Eckel
(or paraphrased, it is not algorithmic, nor can it be)
Engineering process is inherently creative, exploratory, and will always have false starts, dead ends, and learning processes.
"The Engineering Method is the use of heuristics to cause the best change in a poorly understood or uncertain situation within the available resources." -Billy Vaughn Koen
Different engineering disciplines are different. Process Control Model, defined at one end, empirical at the other.
"The defined process control model requires that every piece of work be completely understood. A defined process can be started and allowed to run until completion, with the same results every time. The empirical process control model provides and exercises control through frequent inspection and adaptation for processes that are imperfectly defined and generate unpredictable and unrepeatable outputs." -Ken Schwaber and mike Beedle, SCRUM
Engineering which has expensive construction requires are defined.
"The conversion of an idea to an artifact, which engages both the designer and the maker, is a complex and subtle process that will always be far closer to art than to science." -Eugene S Ferguson
(31:18)
"At first sight the idea of any rules or principles being superimposed on the creative mind seems more likely to hinder than to help, but this is really quite untrue in practice. Disciplined thinking focuses inspiration rather than blinkers it." -Gordon Glegg
(38:00)
Deflection theory for suspension bridges. Tacoma Narrows bridge. Deck so thin that it had aerodynamic properties that exciting resonant frequency.
Engineers adopted formal methods to save money. Predicting failure point makes it possible to reduce safety factor.
Structural analyses (indeed any engineering calculations) must be employed with caution and judgement, because mathematical models are always less complex than actual structures, processes, or machines." -Eugene S Ferguson
Engineering driven by practitioners but refined by academics.
Robert Hook, 1671
(45:51)
Sagrada Familia
(49:00)What is Software Engineering?
Structural engineering is the science and art of designing and making, with economy and elegance, ... structures so that they can safely resist the forces to which they may be subjected.
-Structural Engineers Association
In structural engineering the engineers create diagrams and specifications which are given to builders. Historically we map this onto SE by thinking of the designers as creating specifications for the coders. But this hasn't worked well. Are coders really builders?
The source code is not the solution. It is a design document. It is what the compiler that constructs the system that actually provides the solution.
For structural engineering the most expensive phase was construction. But for SE the compiling is the cheapest. With continuous integration this phase is effectively free.
Jack Reeves, what is software design? (http://www.developerdotstar.com/mag/articles/PDF/DevDotStar_Reeves_CodeAsDesign.pdf)
Dave Thomas said XP processes tightly coupled.
Kent Beck wrote first XP book
If you look at the 13 processes, they can be arranged along a continuum of the amount of feedback they give and the scale at which it is given. From the processes that provide the most immediate feedback with the smallest scope is pair programming. At the other end we have practices that give valuable feedback but at a large scale of time and effort in short releases.
pair programming
unit testing
system metaphor
continuous integration
on-site customer
collective ownership
acceptance testing
planning game
short releases.
One suggestion: don't use languages that enable mutable state! (ha)
platform/application divide.
Glenn: stop using unsafe languages for applications.
formal methods to prove validity and security of small micro-kernels. formal methods now practical for well restricted domain.
Glenn Vanderburg, First.io, glenn@vanderburg.org or @glv
No comments:
Post a Comment