Re: What is the equivalent of x86 "BIOS extension"

Brian Pomerantz (bapper@piratehaven.org)
Wed, 17 Nov 1999 09:02:25 -0800

On Wed, Nov 17, 1999 at 02:51:39PM +0530, T. P. Saravanan wrote:
> We are making a storage controller.
>
> If booting has to be supported from storage controller,
> how can it be done? (For the drivers will be loaded only after linux
> has loaded, and therfore, cannot read from the storage controller for
> boot.)
>
> In x86 there "Expansion ROM" on the controller can contain "BIOS
> extension"
> which the x86 BIOS will use to load the boot code.
>
> How is this handled in Alpha (in context of Linux)?
>

I don't know the details of how it works, just what I've observed. If
you run the Alpha machine under Alpha BIOS mode (usually for NT), then
they will scan for x86 BIOS controllers and execute it with x86
emulation. I have an Adaptec SCSI controller on my Miata which has no
support for Alpha built into, but when I'm running in the Alpha BIOS
mode I can boot from it. If I try to use SRM BIOS, the card is never
seen and I can't boot from a device attached to it. I assume you want
to make your controller work under SRM as well as Alpha BIOS. I would
expect that you need to get in touch with Compaq to get specs on how
SRM works.

BAPper