OS-9 is and never was an "embedded Unix". It has a genealogy independent from any of the Unices. It was originally developed in assembly, as an OS on which to r

OS-9 is and never was an "embedded Unix". It has a genealogy independent from any of the Unices. It was originally developed in assembly, as an OS on which to run BASIC09 on a Motorola 6809. BASIC09 is interesting in itself: it compiled to an intermediate byte-code, which made it very fast compared to other interpreters. OS-9 did, however, have something called a "unix emulation shell" - which basically means an sh clone with some unix compatibility libraries to back it. Sort of like the posix libraries for Windows.