[OpenBIOS] Why protected mode?

Timothy J. Massey tmassey at iname.com
Thu Jul 15 13:56:00 CEST 1999


On Thu, 15 Jul 1999 12:31:48 -0400 (EDT), Kevin P Lawton wrote:

>Also IMHO, by far their greatest mistake in history
>was when they went to a new protected mode environment
>in the 286, they carried forward the segmentation
>architecture.

But they had to.  The 286 is a 16-bit processor.  Without segmented memory,
you would be limited to 64k of memory...  Leaving protected mode out of it,
the rest of the 286 was merely an evolution of the 80186:  a change from a
20-bit memory bus to a 24-bit.  That's the only real change.  Of course,
there *is* protected mode...

Only with a 32-bit processor can you realistically eliminate segmented
memory.

Tim Massey



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