[comp.sys.ibm.pc] 80386 protected mode

jaz@abvax.UUCP (Jack A. Zucker) (06/27/89)

I am going to be writing a ram disk driver that will need to access memory
above the 8mb range. Because of this, I'll obviously need to use protected 
mode. I'm considering using v86 mode and using paging but I would also be
interested in a full protected mode version. I'd be running dos in v86 mode
either way. The difference would be that we'd have to write protected mode
device drivers for all the async interrupts. In our case, that would be the
NMI, timer, serial, as well as device interrupts for the ram disk, etc. Does
anyone have any experience doing this sort of thing ? If so, I'd be very
interested in any feedback. If this is not enough info, let me know.
-Jaz

daveb@sunybcs.uucp (Dave Borkowski) (06/29/89)

In article <774@abvax.UUCP> jaz@abvax.UUCP (Jack A. Zucker) writes:
>I am going to be writing a ram disk driver that will need to access memory
>above the 8mb range. Because of this, I'll obviously need to use protected 
>mode. I'm considering using v86 mode and using paging but I would also be
>interested in a full protected mode version. I'd be running dos in v86 mode


Some good examples to start from can be found in the Intel pubs.

		80386 System Software Writers Guide
		80386 Programmers Reference Manual

They give  flat, segmented and hybrid (demand paged) examples.
The manuals tend to be a bit pricey ($25 each) for their size, but 
worth it. I too am working on a project using protected mode, but not
as ambitious as your talking about. Do you plan to return to DOS or is
this strictly a protected mode application ?