Date: Sat, 27 Jun 1998 17:50:47 +0200 (CEST) From: Andrzej Bialecki <abial@nask.pl> To: Dinesh Nair <dinesh@alphaque.com> Cc: Marc Nicholas <marc@hippocampus.net>, freebsd-small@FreeBSD.ORG Subject: Re: I'm back. Message-ID: <Pine.NEB.3.95.980627174116.22013A-100000@korin.warman.org.pl> In-Reply-To: <Pine.BSF.3.91.980627162639.253C-100000@broker>
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On Sat, 27 Jun 1998, Dinesh Nair wrote:
>
> On Fri, 26 Jun 1998, Andrzej Bialecki wrote:
>
> > What I'd like to do is to be able to access the flash r/w (preferably to
> > mount it) from under running FreeBSD system. Are you saying it works? If
> > yes, then please tell us what you did to achieve this.
>
> off the cuff here, but if the drive is presented as an IDE drive (meaning
> bios handles the mappings), then why cant freebsd just mount the babies ?
Ok, let me make it clear:
* I was mistaken as to the type of the inetrface of this particular flash
- it is plain IDE, not an ISA card which mimicks as an IDE drive using
its own BIOS extension,
* FreeBSD currently uses BIOS services only to load the kernel (I
shouldn't even say "FreeBSD" but just bootloader). BIOS services are
available in real-mode only, while the kernel runs in protected mode
of course.
* Hence, once the kernel is running, the BIOS extensions that the flash
previously loaded are unavailable. It no longer exists as the IDE drive.
The solution to this is to write special driver which uses those real-mode
BIOS services (through vm86 layer) to transfer the data to/from the flash,
and present it as a disk device to the system.
Andrzej Bialecki
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abial@nask.pl | if(halt_per_mth > 0) { fetch("http://www.freebsd.org") }
Research & Academic | "Be open-minded, but don't let your brains to fall out."
Network in Poland | All of the above (and more) is just my personal opinion.
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