On UNIX, the boot code is traditionally found in the directory
/usr/mdec. Some modern UNIX variants keep this tradition up (e.g. OpenBSD) while others have changed the directory layout (e.g. FreeBSD). I was able to find a
/usr/mdec directory in 5th edition UNIX, but not in any of the incomplete earlier versions. No explanation for the name is given.
Where does the name
/usr/mdec come from and what does it mean?