80286 Protected Mode Test

Noel Chiappa jnc at mercury.lcs.mit.edu
Mon Mar 15 09:23:01 CDT 2021

    > From: Guy Sotomayor

    > the LOADALL instructions including all of it's warts (and its inability
    > to switch back from protected mode)

Good to have that confirmed (for the 286; apparently it works in the 386).

    > the other way to get back to real mode from protected mode is via a
    > triple-fault.

Any insight into why IBM didn't use that, but went with the (allegedly slow)
keyboard hack?


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