The extremely practical use for the authors is that they're teaching with it - 6.828 (MIT's OS class) this semester is entirely in xv6 on RISC-V in qemu. In yea

The extremely practical use for the authors is that they're teaching with it - 6.828 (MIT's OS class) this semester is entirely in xv6 on RISC-V in qemu. In years past, lessons were taught from a completed xv6 for x86 and assignments / projects were on top of an incomplete JOS exokernel, also for x86. xv6 has always been a teaching OS, not even a hybrid teaching/production OS like MINIX. (Are you asking about v6 UNIX in general? The practical descendant of that is the BSDs.)