1. A computer-implemented method of isolating a plurality of operating system processes on a particular processor, the method comprising: using software protection for at least two of the operating system processes to prevent each of the at least two operating system processes from accessing memory assigned to the other of the at least two operating system processes and to other processes of the plurality of operating system processes; grouping the plurality of operating system processes into a plurality of protection domains, each of the at least two operating system processes being grouped into a different protection domain; and using hardware protection to prevent one of the at least two operating system processes from accessing memory assigned to another operating system process belonging to a different protection domain from the one of the at least two operating system processes, the hardware protection operating as backup protection to the software protection.