[OpenBIOS] Why protected mode?

Phil King pking at netschools.net
Wed Jul 7 19:22:35 CEST 1999

At 05:28 PM 7/7/99 -0700, you wrote:
>>> 2) Go into protected mode for initial configuration, then exit it to load
>>> the boot code (note that the BIOS service routines would have to run in
>>> real mode in this case).
>>This is how other BIOSs today do it. That is also how you have to do if
>>you strive for IBM-PC BIOS compability.
>And this continues the necessity for either a keyboard or a keyboard
>simulator, does it not? My recollection is that the only way out of
>protected mode (back in 286 days) was through a keyboard reset sequence.

That was only on the '286, which required a processor reset to get back
into real mode and was assisted by the keyboard controller, one of the
Great PC Hacks.  It is not as traumatic with '386 and beyond.


					Phil King
					pking at netschools.net

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