Re: Now I wonder when someoen will port the ICL 2900 architecture and George 3
Used both Multics at STC and VME when STC bought out ICL.
There is already a G3 emulator and the current VME - still in use by some customers actually runs under emulation on Intel hardware - whether this will ever by generally released is another matter.
ICL seemed to by very good at emulation - with ICL1900 and System4 being ones I saw - there were rumours of a 370 emulator but denied.
What was interesting about the emulation was the fact you had multiple instruction decoder boards to allow the different instruction sets to run as well as some intelligence in the various peripheral controllers to allow the newer hardware to work with older OS.
From memory there were several variants - DME which allowed the new hardware to pretend to be the old hardware - just running a lot faster, CME which allowed concurrent emulation with the hardware effectively time slicing between the two instruction sets - useful when moving a workload from the old platform to the new one and I have some bitter memories of using BMEEP which allowed one VM to run under a different instruction set
Biting the hand that feeds IT
