Sunday, March 28, 2010

SEMAT and the origins of Software Engineering

I hope commentators on the SEMAT initiative - on both sides - have read enough history so that the rest of us aren't doomed to listen to a repeat performance of the last 40 years.

Its been interesting for me to follow the initial steps of the Software Engineering Method and Theory (SEMAT) initiative. Reading the SEMAT blog and articles revived memories from when I spent a bunch of years doing research on software engineering foundations. So I'm very curious to see how it progresses. Unfortunately, the initial buzz reminds me a lot of the fledgling steps of the original "software engineering" movement and I hope we don't waste an opportunity to deal with an important issue by continuing to bitch about the meaning of the word engineering.

Its hard to argue with the SEMAT Call to Action - especially the identification of immature practices. We do lack a theoretical foundation that provides both an explanation for the practices that have proven to be useful and a justification for proposing approaches for further improvement. (unless of course you believe we have already reached the pinnacle for software development effectiveness)

Many of the responses to the initial Vision and first workshop (google blog search semat,  twitter search #semat) are made by knowledgeable and insightful commentators. However, a great deal of what I read is simply a restatement of arguements that have been made in our discipline - that were often made more eloquently and constructively - for more than 40 years. Perhaps catching up with a bit of history can focus people on providing an improvement rather than rehashing old opinions.


P. Naur and B. Randell, (Eds.). Software Engineering: Report of a conference sponsored by the NATO Science Committee, Garmisch, Germany, 7-11 Oct. 1968, Brussels, Scientific Affairs Division, NATO (1969) 231pp.B. Randell and J.N. Buxton, (Eds.). Software Engineering Techniques: Report of a conference sponsored by the NATO Science Committee, Rome, Italy, 27-31 Oct. 1969, Brussels, Scientific Affairs Division, NATO (1970) 164pp.
The transcripts of the original two software engineering conferences are available online. They contain many working papers,  but most importantly, also transcribed debates between the participants which capture very interesting views on both sides. As a bonus, there is also the first analogies I can find between software design and the design theories of Christopher Alexander


The NATO conferences on software engineering were held in 1968 and 1969 and were intended to provoke ideas for improving software development. Indeed the term "software engineering" was meant to provoke and not to dictate a frame of mind needed to produce dependable software.
The phrase ‘software engineering’ was deliberately chosen as being provocative, in implying the need for software manufacture to be based on the types of theoretical foundations and practical disciplines, that are traditional in the established branches of engineering (1968, Preface)
There were many debates about the nature of engineering and whether or not it can be applied in software development which elicited useful insights into the nature of software development. Indeed, some of those comments allude to understandings which are considered relatively recent, such as agile development.
“[Naur] In my terms design consists of:
Flowchart until you think you understand the problem.
Write code until you realise that you don’t.
Go back and re-do the flowchart.
Write some more code and iterate to what you feel is the correct solution.” (1968 Report)
Additionally, there were points made, such as the usefulness of mathematical formalisms for software development, which are still not satisfactorily addressed today.

The important take away is that the result of the first software engineering conference was debate. The term engineering was put forward to provoke discussion on a commonly agreed set of problems - a Call to Action.

The problem was when they reconvened in 1969 for the next conference. The thing you notice in the transcripts is that the topic of debate has changed. There is no longer a sense of how should we frame our thinking to resolve these issues. The notion that software development could be "engineered" had taken hold. The only question now was, how. This was also explicitly pointed out by the editors of the transcripts:
Unlike the first conference, at which it was fully accepted that the term software engineering expressed a need rather than a reality, in Rome there was already a slight 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 International 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 support 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" (Editor's report)
(btw: anyone who thinks they have a witty and insightful take on why software development isn't like engineering should read "Masterpiece Engineering")

This communication gap in the 2nd software engineering conference happened very quickly and was not overcome. This resulted in a whole group of people who could have made useful contributions being removed from the debate.
The sense of urgency in the face of common problems was not so apparent as at Garmisch [1968]. Instead, a lack of communication between different sections of the participants became, in the editors’ opinions at least, a dominant feature.” (Editor's report)
Its pretty clear in the external commentary of the first SEMAT workshop that this is happening again. Whether or not they have chosen to remove themselves from the effort, there is now a significant group of people who could be helping to achieve the goals of the Call to Action who are simply not taking part.

There is always risk that the subject of debate gets 'highjacked' by a particular side - such as those who believe that software development can be engineered. Using the word "highjacked" is very emotive and implies a deliberate misdirection of a movement, but in reality it is that people are at risk of pushing an approach that simply conforms to their preconceived world-view. Many of the comments on SEMAT and software engineering in general appear obvious to their authors and their like-minded colleagues. But they make little sense to the people on the other side. They are based on incommensurable viewpoints. That is, you simply can't find common basis for comparing them.

We each have a worldview through which we understand our domain (in this case software development). Those worldviews can be incommensurable like the pro- and anti- software engineering camps. But there is no right or wrong answer answer here. The only thing that matters is whether or they provide useful suggestions for improving our discipline.

I don't know if engineering is the most useful paradigm through which software development can be improved. However, you only have to have a basic understanding of philosophy of science to understand that its not possible to tell until after theories have been developed, evaluated, and falsified.

The SEMAT Call to Action captures issues that exist in software development. The software-engineering group needs to devise theories which can be proven useful in resolving those issues. The its-not-engineering proponents should be doing the same. It will help everyone if the debate between them continues instead of becoming a divide that stifles possibilities.

I'll finish off with my favourite quote by Dijkstra and Randell in the '69 transcripts:
“Dijkstra: I would like to comment on the distinction that has been made between practical and theoretical people. I must stress that I feel this distinction to be obsolete, worn out, and fruitless. It is no good, if you want to do anything reasonable, to think you can work with such simple notions. Its inadequacy, amongst other things, is shown by the fact that I absolutely refuse to regard myself as either impractical or not theoretical.
...
What is actually happening, I am afraid, is that we all tell each other and ourselves that software engineering techniques should be improved considerably, because there is a crisis. But there are a few boundary conditions which apparently have to be satisfied. I will list them for you:
We may not change our thinking habits.
We may not change our programming tools.
We may not change our hardware.
We may not change our tasks.
We may not change the organisational set-up in which the work has to be done.
Now under these five immutable boundary conditions, we have to try to improve matters. This is utterly ridiculous. Thank you. (Applause).
Randell: ... ‘There’s none so blind as them that won’t see.’ ... If you have people who are completely stuck in their own ways, whether these are ways of running large projects without regard for possible new techniques, or whether these are ways of concentrating all research into areas of ever smaller relevance or importance, almost no technique that I know of is going to get these two types of people to communicate. ... You have to have good will. You have to have means for people to find out that what the others talk is occasionally sense. This conference may occasionally have done a little bit of that. I wish it had done a lot more. It has indicated what a terrible gulf we so stupidly have made for ourselves.

3 comments:

  1. Reading this makes me feel that we haven't made any progress in software for 40 years.

    ReplyDelete
  2. Very nice analysis. Thanks for reminding us of our history!

    ReplyDelete