How to use int 13 while BSD is running

[Jason Dictos]

Thanks for the reply, however I'm looking for a more DMPI style interface
while in protected mode. If we didn't need to be in protected mode, then I'd
just leave it the way it is-us booting into DR DOS and using inline assembly
to access int 13. However what we're trying to do is move to a 32 bit kernel
environment, while still retaining access to realmode interrupts.

-Jason 

-----Original Message-----
From: John Baldwin [mailto:jhb at FreeBSD.org] 
Sent: Wednesday, March 10, 2004 7:52 AM
To: Jason Dictos
Cc: 'freebsd-hardware at freebsd.org'
Subject: Re: How to use int 13 while BSD is running

On Tuesday 09 March 2004 04:24 pm, Jason Dictos wrote:
> Hello,
>
> 	I'm investigating what resources are out there for accessing bios 
> addressable devices while BSD is up and running. The situation is 
> this, currently we licenses Caldera DOS for a program we wrote which 
> uses the
> int13 extensions to manipulate the systems hard drive (i.e. to recover 
> partition tables and what not). This forces our application to be 
> written in 16 bit mode, but it does allows us to not have to worry 
> about loading any driver which would be hardware specific to access 
> the hard drive. Is there any way to write a driver for BSD which would 
> put the processor into real mode, therefore allowing us to use the int 
> 13 api of the bios to read and write hard drives? That way we could 
> package a stripped down BSD kernel which loaded our driver and gave 
> our application access to hard disks without having to load any device
driver.
>
> Apologies in advance if this is the wrong mailing list,

Look at the loader in src/sys/boot.   It is a 32-bit C app that uses BIOS 
calls to access the disk.  It uses a psuedo-kernel called BTX to manage
interrupts in vm86 mode and run BIOS code in vm86 mode.  You can probably
port your software to being a custom loader that uses boot2 to boot off of a
floppy.  You can also use cdboot to boot a loader off of a CD or pxeboot to
boot a loader image over the network.  The loader uses libstand which
provides several useful things like malloc/free, some basic filesystem
support, etc.

--
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/ "Power
Users Use the Power to Serve"  =  http://www.FreeBSD.org

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