Peter J. Cranstone wrote:
Currently Windows, Linux and Unix only use two levels of privilege - Ring 3
and Ring 0. Everybody and there uncle's code want to run at Ring 0. Another
really bad idea, as once I introduce a network/video/keyboard/whatever
driver at that level I can execute malicious code. From there I can control
the machine.
You'd need a new hardware architecture for ring 1 drivers to be
worth it. The trouble is that drivers can initiate DMA operations
against physical memory. Unless you devise some system where the OS can
veto DMA operations, protection in the CPU is worthless.
