Abstract :
The complexity of a mainframe is determined by the need to run an existing operating system and by the performance requirement. For the VME operating system the smaller processor of the two mainframe designs contains about 250 K logic gates and 4 M bits of fast static RAM organised as a 32 bit wide data flow. Historically equipment of this complexity required a computer room environment to cope with the dissipation and noise. The advent of CMOS gate arrays made it possible to develop the smaller mainframe for an office environment, and the advent of low cost high performance fibre optics made it possible to distribute the system across several offices. The paper shows how
