Curiosity of the 286 archictecture - question
Posted: Mon Sep 02, 2013 6:09 pm
Came across a manual for the 286, browsed through it for fun and I came across this:
But afaik.. the 286 only had a 24 bit address bus, hence the 24 base in the gdt (which we will see today for backward compatibility). So without translation, our base+effective addr just goes out on the bus and would wrap at 16mb.
What is meant here by "1gb logical address space"?
From what I know, the 286 didn't have paging, the closest you could get was maybe using not present faults to page in some data.The memory architecture of the Protected Mode 80286 represents a significant advance over that of the 8086. The physical address space has been increased from 1 megabyte to 16 megabytes (2^(24) bytes), while the virtual address space (i.e., the address space visible to a program) has been increased from 1 megabyte to 1 gigabyte (2^(30) bytes).
But afaik.. the 286 only had a 24 bit address bus, hence the 24 base in the gdt (which we will see today for backward compatibility). So without translation, our base+effective addr just goes out on the bus and would wrap at 16mb.
What is meant here by "1gb logical address space"?