Just the other day I got Bourne's original Bourne shell running on a modern system (as part of Fuzix development). I don't know which version, but it's badged a

Just the other day I got Bourne's original Bourne shell running on a modern system (as part of Fuzix development). I don't know which version, but it's badged as coming from V7. I kept finding places which needed adjustment for a modern architecture... and then I looked more closer and saw that they were actually fine. About the only thing I needed to do in the end was fix some headers, rename a symbol which was clashing with a modern utility function, and change the directory reading stuff to use opendir() instead of read(). Everything else just worked on a modern 64-bit system. (It had already been converted from K&R to ANSI C in an earlier pass by someone else.) Good grief, that code is clean. Incomprehensible, but clean.