Jim Dempsey, an alum of the OS/8 group at DEC, developed ETOS for Educomp (later Quodata) for the PDP-8/E; this was a true virtual machine operating system in the spirit of IBM’s VM/370, and a special board was required
to optionally trap JMP and JMS instructions; this was enabled after an emulated CIF instruction so that the actual change of instruction field could be emulated when the JMP or JMS was attempted.

After leaving Quodata and founding Network-Systems Design in 1976, Dempsey went on to develop
OMNI-8, first installed at Ripon College; initially it was priced at $4900, several hundred copies were sold. The OMNI-8 operating system supported the enlarged PDP-8 address space of the CESI (Computer Extension Systems Inc) memory cards, and when CESI began making PDP-8 clones, OMNI-8 was extended to support asymmetric multiprocessors (one CPU handled the I/O). The end of OMNI-8 development came around 1990. Dumps of the ETOS kernel and drivers survive in various places, and Jim Dempsey still has the full source for OMNI-8.