Alan JoWhen interrupt
Mode Switching is the reason of User Space and Kernel Space share same linear memory space because it is frequent, reducing overhead)
to kernel mode or user mode
A full process switch is not performed, just a mode switch within the same process! (saves overheads for two process switches.)
hardware protection
- dual mode - user mode / kernel mode - need hardware support
- hardware protect
protected processor register in intel CPL(current), RPL(request), DPL(descriptor)
Mode Switching Notion
supervisor = system = monitor = kernel before mode intel real mode, protected mode