I stumbled across this the other day - Old DOS Never dies... ( ia801209.us.archive.org )
This should boot up on your run of the mill S-100 based system with an 8086. Maybe an 8080 too? Also, it reportedly runs under #simH as a virtual machine. According to some, this is the earliest known version of #86-DOS, not long after replacing #QDOS as its successor....
