The original Series 39 introduced the "S3L" (whose corrupt pronunciation resulted in the name "Estriel"[1]: 341 ) processors and microcodes, and a nodal architecture, which is a form of Non-Uniform Memory Access.
The Series 39 range introduced Nodal Architecture, a novel implementation of distributed shared memory that can be seen as a hybrid of a multiprocessor system and a cluster design.
[2] The semaphore instructions prove their worth by controlling access to the shared writable memory segments while allowing the contents to be moved around efficiently.
Overall, a well configured Series 39 with VME had an architecture which can provide a significant degree of proofing against disasters, a nod to the abortive VME/T ideas of the previous decade.
To provide OVS, an emulator for the SY instruction set, together with input/output functionality and a platform abstraction layer, were deployed on the VxWorks operating system.
The transition of the "ICL mainframe" to a pure software product was thus complete, enabling Fujitsu to concentrate on VME support and development without having to keep up with hardware technology.