[hadeharian]

What people don't always understand is outside of the tech world, there are people who still think computer upgrades are unnecessary expenditures. It's true that the theoretical lifetime of a computer is probably something like 50 years, minus the hard drive replacement and the power supply which will generally go bad much quicker.

The more difficult thing is in a field like aeronautics any minor changes have the possibility of generating catastrophic events. In these situations, the cost of replacement, and testing, and phasing stuff in is enormously high and the risk is obscene when change needs to be made.