Using int 13 while BSD is running

[Jason Dictos]

DD's great and all, but I'm not talking about which method to use, I'm
talking about a guaranteed way to access a device without having to rely on
any device drivers. 

Take a look at this: http://sourceforge.net/projects/lrmi/

This provides a dpmi style interface for linux and bsd, thats exactly what I
was looking for.

Thanks,
-Jason

-----Original Message-----
From: Jerry McAllister [mailto:jerrymc at clunix.cl.msu.edu] 
Sent: Wednesday, March 10, 2004 8:14 AM
To: doublef at tele-kom.ru
Cc: jason.dictos at yosemitetech.com; freebsd-questions at freebsd.org
Subject: Re: Using int 13 while BSD is running

> 
> --Signature=_Wed__10_Mar_2004_08_12_00_+0300_m3U9Vu7vS=cMcNXd
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> 
> On Tue, 9 Mar 2004 14:03:34 -0800
> Jason Dictos <jason.dictos at yosemitetech.com> probably wrote:
> 
> > 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.
> 
> Through the /dev/ad[0-9] (ide) or /dev/da[0-9] (scsi/usb) you can get 
> access to any byte in you harddrive. They `look like' ordinary files 
> to most programs. Just seek the appropriate number of bytes and read 
> what you want (0-512 is the mbr, for example). You don't even need to 
> write a line in assembly for that, just plain C (or even shell-script, 
> if you prefer that).

Gee whiz, just let dd(1) do it for you.   It can seek to any position
and read any number of bytes of a disk.    If it gets ornery, set the
block size to 1 byte - a little slow and efficient, but then it won't have
trouble with other block arrangements.

////jerry

> 
> > 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?
> 
> Putting the cpu back into real mode is kind of perversion. And I don't 
> think FreeBSD provides any real mode interface. Whatever you would see 
> in real mode, you can bet it isn't a FreeBSD driver for your harddrive.
> 
> --
> DoubleF
> Romeo wasn't bilked in a day.
> 		-- Walt Kelly, "Ten Ever-Lovin' Blue-Eyed Years With
> 		   Pogo"
> 
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> 


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