While many of those computer systems did have problems, it's important to note just how well NASA's aerospace applications work:
This software never crashes. It never needs to be re-booted. This software is bug-free. It is perfect, as perfect as human beings have achieved. Consider these stats: the last three versions of the program -- each 420,000 lines long-had just one error each. The last 11 versions of this software had a total of 17 errors. Commercial programs of equivalent complexity would have 5,000 errors.Which is really how it should be for something that pilots a space shuttle, but then, writing software for such an focused set of criteria makes things somewhat easier to implement:
Admittedly they have a lot of advantages over the rest of the software world. They have a single product: one program that flies one spaceship. They understand their software intimately, and they get more familiar with it all the time. The group has one customer, a smart one. And money is not the critical constraint: the groups $35 million per year budget is a trivial slice of the NASA pie, but on a dollars-per-line basis, it makes the group among the nation's most expensive software organizations.The shuttle software group is one of just four outfits in the world to win the coveted Level 5 ranking of the federal governments Software Engineering Institute ( SEI ) a measure of the sophistication and reliability of the way they do their work. [Thanks to the Laboratorium and norton for all the info]
And that's the point: the shuttle process is so extreme, the drive for perfection is so focused, that it reveals what's required to achieve relentless execution. The most important things the shuttle group does -- carefully planning the software in advance, writing no code until the design is complete, making no changes without supporting blueprints, keeping a completely accurate record of the code -- are not expensive. The process isn't even rocket science. Its standard practice in almost every engineering discipline except software engineering.