Talk:Real mode

Intel-specific

The term 'real mode' is Intel-specific. Pretty much all machines with memory management (including the PDP-10, PDP-11 and VAX) start up with a straight mapping from the CPU's address space to physical main memory. The OS on these machines sets things (e.g. mapping tables) up, then turns on memory management; all further memory references go through the memory management. That un-mapped mode is never used again, though, and the term 'real mode' is not used to describe that initial operating mode.

The thing that's definitely specific to Intel's 'real mode' is that it's used, post-bootstrap, to support code written for older CPU models (which all have memory management, though; the 8086 code generates mostly only 16-bit addresses, which the hardware runs though the segmentation hardware to produce physical memory addresses). It's not just a 'bootstrap' mode, it's mostly a backward compatability mode. Jnc (talk) 16:50, 2 March 2021 (CET)