About the memory management in the Bourne shell (via) is a collection of discussions about the original Bourne shell's creative, interesting, and infamous approach to memory management in the original Unix memory allocation scheme. If you like this kind of thing, it's worth reading through and decoding things.

(It also links to a recording of Stephen Bourne's BSDCan 2015 talk "Early days of Unix and design of sh", which I haven't watched yet but keep seeing links to. Someday.)