6 posts
Cleanroom verification requires generating and discharging proof obligations.
Cleanroom software engineering demands that you prove your code correct before you compile it. That sounds noble until you spend three hours writing loop…
Cleanroom software engineering cuts defect rates by 100×, but full adoption requires separate test teams and formal proofs.
Cleanroom software engineering delivers 0.1 defects per thousand lines of code. The industry average is 10 to 50. The catch is that full Cleanroom requires you…
IBM's Cleanroom engineering achieved defect rates 100× better than industry average, then faded into obscurity.
IBM's Cleanroom software engineering process delivered 0.1 defects per thousand lines of code. The industry average at the time was between 10 and 50. The…
Cleanroom software engineering promised zero-defect increments through mathematical verification instead of debugging.
The software industry average in the 1980s was 30 to 60 defects per thousand lines of code. IBM's Cleanroom team shipped a 20,000-line compiler increment with…
Box structures force you to define what a module does, what it remembers, and how it works as three separate, verifiable layers.
You write the code first, then write the tests, then discover the code was wrong. That is the standard loop. It is also why debugging consumes half of most…
IBM's Cleanroom engineering process achieved defect rates 100× better than industry average by preventing bugs instead of finding them.
IBM shipped a NASA satellite control system with 0.1 defects per thousand lines of code. The industry average at the time was between 10 and 50. They did not…