Re: [SeaBIOS] First access to the block drive

[Kevin O'Connor]

On Thu, Mar 01, 2012 at 05:39:25PM +0900, Daniel Castro wrote:
> Hello all,
>
> The xen pv drivers are almost done.
>
> When I start the booting process from hda seabios tries to read lba at
> 0 (sector 0) buffer (buf_fl) to 7c00 count 0 operation 0 (read)
> command 1 (unlisted)
> I do not understand count 0 and command 1.
> Should it be count 1, for the first sector on the drive and a command
> such as listed in drive.h?
>
> Is this normal? Am I missing something?

I don't understand what you are reporting/asking.

The code at boot.c:boot_disk() issues a legacy bios read (int 13 ah=2)
of the first sector (count=1).

-Kevin

First access to the block drive

[Daniel Castro]

On Mon, Mar 5, 2012 at 4:18 AM, Kevin O'Connor <[e-mail]> wrote:
> On Thu, Mar 01, 2012 at 05:39:25PM +0900, Daniel Castro wrote:
> > Hello all,
> >
> > The xen pv drivers are almost done.
> >
> > When I start the booting process from hda seabios tries to read lba at
> > 0 (sector 0) buffer (buf_fl) to 7c00 count 0 operation 0 (read)
> > command 1 (unlisted)
> > I do not understand count 0 and command 1.
> > Should it be count 1, for the first sector on the drive and a command
> > such as listed in drive.h?
> >
> > Is this normal? Am I missing something?
> > Thanks for the response Kevin, I am debugging the operation on a xen drive.
> > Right now the drive fron end is initialized correctly and connects to
> > the back end, then boot proceeds. But on the first operation is am
> > getting an command=1 and count=0.

And that seems awkward.

I will take a look at boot_disk() to trace the call.
> I don't understand what you are reporting/asking.
>
> The code at boot.c:boot_disk() issues a legacy bios read (int 13 ah=2)
> of the first sector (count=1).
>
> -Kevin

Thanks,

Daniel



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| |   | Daniel Castro,                |
| |   | Consultant/Programmer.|
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