The "OS" (or rather "kernel") was actually the VM which was implemented in microcode and BCPL. The Smalltalk code within the image was completely abstracted away from the physical machine. In today's terms it was rather the "userland", not a full OS.

Oberon is both a programming language and an operating system used mostly for teaching, much like e.g. xv6 or xinu. Similar to the latter, Wirth has written text books about the system, some of which can be downloaded for free (see https://projectoberon.net/ for the PDF links).

Thanks. In contrast to Smalltalk or Lisp, Oberon is originally a native language, and the Oberon System originally was conceived as the native operating system of the Ceres computer used for teaching in the nineties at ETH Zurich. So there is no image as in Lisp or Smalltalk. Oberon lives on today in the form of various dialects and derivatives (such as my Oberon+ or Micron languages, see https://github.com/rochus-keller/oberon and https://github.com/rochus-keller/micron). There are indeed Oberon implementations which run on Java or ECMA 335 runtimes, which is possible due to the very restricted pointer handling and memory management of Oberon.

Thanks. There is actually also an i386 version of the system in the repository, where I modified the kernel so it runs with Multiboot, making installations much easier. An essential achievement for both platforms were the stand-alone tools, i.e. I can compile and link the whole Oberon system on Linux or any other platform (see https://github.com/rochus-keller/op2/). I even implemented an IDE which I used for the development (see https://github.com/rochus-keller/activeoberon/).