While I’m ranting on software quality…

For those interested in both the hard and soft sides of quality, I highly recommend the “Feynman Appendix” of the Rogers Commission report on the Columbia disaster. 

Software gets a bad rap from “harder” engineering disciplines, but what was the one component of the shuttle whose engineering and quality “attitude” Feynman praised?

To summarize then, the computer software checking system and attitude is of the highest quality. There appears to be no process of gradually fooling oneself while degrading standards so characteristic of the Solid Rocket Booster or Space Shuttle Main Engine safety systems.

The NASA developers take the only approach that can work with machines that are as complex as mission-critical software.  They build the quality in step-by-step…

The software is checked very carefully in a bottom-up fashion. First, each new line of code is checked, then sections of code or modules with special functions are verified. The scope is increased step by step until the new changes are incorporated into a complete system and checked. This complete output is considered the final product, newly released.

Then different group(s) test by inspection and simulation…

But completely independently there is an independent verification group, that takes an adversary attitude to the software development group, and tests and verifies the software as if it were a customer of the delivered product. There is additional verification in using the new programs in simulators, etc.

I also like the knowledge management touchpoint as well… 

A discovery of an error during verification testing is considered very serious, and its origin studied very carefully to avoid such mistakes in the future.


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