Re: Real-Mode of Intel processors!!

[Ketan Mukadam <ketan@iitk.ac.in>]

On Fri, 1 Mar 2002, Thomas Abraham wrote:

==>Hi Ketan,
==>  This is in response to your query on real mode.
==>
==>Intel processors can work in two modes. Real mode and
==>Protected mode. In real mode, processor works with 16
==>bits. All the memory managment and process mangament
==>features are turned off in this mode. But in protected
==>mode these features are turned on which is very
==>essentail for an operating system.
==>
==> Now when the computer boots up, the processor is
==>initally in reak mode. Now OS is boot starped and if
==>that OS need to work in protected mode of the Intel
==>processors, then it executes an instruction to switch
==>to protected mode and utilize process features.
==>
==>   Maybe this explanation is incomplete and vague. If
==>you need mode info please mail to me.
==>
==>Regards,
==>Thomas
==>
==>( This is the first time I am replaying to a query on
==>a mailing list.)

first of all thank you Thomas for replying.

Actually what you have written, that stuff i already know, but what i wanted to
know is that where the real-mode is used except bootstrapping. Once ur OS gets
booted the processor is switched in protected mode.[ This is true of Linux ] Now
in which situations it returns to real-mode or is it that it never goes into
real-mode after booting??

[Sorry,but I prefer to have the discussion on the mailing list. Is this
off-topic?]

Regards
Ketan


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