Title: Your Letters - The Editor's Replies

The following was posted on accu-general and, with the consent of the author is reprinted here.

Although I agree with what he has said in theory, I have to wonder if Francis has every worked in a real company doing real engineering work. Engineering is all about building the product the customer needs for an acceptable price in an acceptable time. There is neither the time nor money to produce a perfect and elegant product in all engineering projects. As such I am a bit offended that he states that I am unprofessional because I have had ship non-perfect products when there has been no budget, or time to do otherwise. We are not artists that can sit back in our lofts perfecting the right blue to go with a yellow shape, we are engineers that live with real world constraints, some of these are just attempting to do the impossible in impossible conditions.

There is a world of difference in engineering between "life threatening products" and the rest. Life threatening projects have normally got different goals, time scales and resources available to them than the rest of us. On the Airbus control system for example (if I remember correctly) there were three different project teams working on three different hardware platforms writing the same software. The three systems have to agree for the 'system' to agree. A product cannot go into service just because the programmers say the software works, it has to be rigorously tested first and in some cases using "formal methods" prove it does what the spec required it to do under all situations.

Compare that with the way it normally works - your manager comes up to you wants a modification by the end of the week, and it must shipped otherwise a X millions sale is lost. You are then under considerable stress the do the work ASAP. In most companies X millions sales cannot just be 'lost' because you could not perfect the modification. You have to ship it then, and fix the bugs / features later. That is a fact of life or in some companies your job!

In the company I work for we do attempt to stop this sort of thing happening but in my personal experience this sort of things goes on all the time. This is not a problem of programmers but of management / sales / accounts / directors / customers. Unless Francis is suggesting changing the complete makeup of the western world all that he is suggesting is a very fast way for some people to be fired.

In theory, theory and practice are the same time, but in practice they are not.

Disgruntled of Kingston-Upon-Thames!

It seems to me that the whole of the above is based on a false reading of what I wrote. How the writer deduces that I am advocating only perfect software should be shipped when I wrote:

Please carefully note the phrase 'known, non-fatal, defects' how is that commensurate with the writer's:

I stand by what I wrote, and any reasonable interpretation of it.