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Hardware-isolated Kernel

05/21/2009

I can imagine a computer with two CPUs. But not two identical CPUs but on the contrary, two CPUs that are very different each other.

One (lets calle it "CPU-0") is very low profile whereas the other ("CPU-1") is full featured. Each one has its own separate physical memory; they don't share memory and possibly no storage either; they are totally isolated from each other.

CPU-0 runs the Kernel and it does in "real mode": no virtual memory, no protected mode. As a matter of fact, this CPU does not implement those advanced technologies.

CPU-1 runs the user processes in protected mode; possible this is the only way it can operate: in cannot be "switched back to real mode". The OS Shell also runs in CPU-1 as an ordinary user process. Both Kernel and applications runs concurrently implying that the Kernel never stops: there is no switching between Kernel and User modes.

The only link between the two CPUs (apart from the power supply) is by the mean of hardware interrupt requests. Actually, all processes in CPU-1 runs as IRS routines. The Kernel switches processes by issuing hardware interrupts to CPU-1. Similarly, CPU-1 notifies the Kernel via hardware interrupts. Or maybe there is a "secret path" between the two. We may call it "Inter-Bus" or maybe: "Tunel".

Estrange architecture... Just another idea among many.