Nomenclature
When New Range was first launched in October 1974, its operating system was referred to as "System B". By the time it was first delivered it had become "VME/B".
VME/K was developed independently (according to Campbell-Kelly, "on a whim of Ed Mack"), and was delivered later with the smaller mainframes such as the 2960.
Following a financial crisis in 1980, new management was brought into ICL (Christopher Laidlaw as chairman, and Robb Wilmot as managing director). An early decision of the new management was to drop VME/K. Thus in July 1981 "VME2900" was launched: although presented to the customer base as a merger of VME/B and VME/K, it was in reality the VME/B base with a few selected features from VME/K grafted on. This provided the opportunity to drop some obsolescent features, which remained available to customers who needed them in the form of the "BONVME" option.
The "2900" suffix was dropped at System Version 213 (SV213) when ICL launched Series 39 in 1985 as the successor to the original 2900 series; and the "Open" prefix was added after SV294 when VME became capable of hosting applications written originally for Unix through a UNIX System V Release 3 based subsystem using the ASCII character encoding adapted to run under VME.
The most recent incarnations of VME run as a hosted subsystem, called superNova, within Microsoft Windows, or SUSE or Red Hat Enterprise Linux on x86-64 hardware.
Read more about this topic: ICL VME