- x86 Processors operate in either protected or real mode
- Real mode: Backwards compatibility mode
- Protected mode: All user programs need to use system calls to get access to resources
- Real mode allows a process to directly address memory and has RAM limited to 1MB. This is used for example when emulating 8086 programs directly
https://pdos.csail.mit.edu/6.828/2010/readings/i386/s05_01.htm contains some pretty good pictures of a translation
pokhym 