One great thing about the blogowebs is that you never know what sorts of posts you might run across, and this post about self-modifying code and the Space Shuttle OS is a prime example of that:
And it reminded me of my days during the early 1990s working as a software engineer on the Space Shuttle operating system (FCOS). Many people don’t know that the Space Shuttle OS implements self-modifying code for the purpose of “fault-tolerance”. The Shuttle computer systems consist of four primary computers running the same software, and a fifth backup computer running different software that is equal in functionality. The goal is to be Fail Operational if one or more computers fail, and Fail Safe if all primary computers fail; this is called a Fail Operational/Fail Safe system.
An interesting read, especially if you’re a software developer who doesn’t work in embedded systems but likes to read about them.