Re: [Qemu-discuss] response to BIOS int 0x13 calls

[bilsch]

On 03/11/2016 08:56 AM, Dale R. Worley wrote:
> bilsch<address@hidden>  writes:
> > I'm a low energy QEMU user.  I use it for running a 'hobby' OS that is
> > little more than a boot sector.  It has a program that calls int 0x13
> > ah=0x48 to get the number of sectors on the hard drive.  If the call
> > returns CF=1 it means the call was unsuccessful (and presumably the # of
> > sectors info is invalid).  If I copy the 'OS' containing this BIOS call
> > to a partition on the actual hard drive and boot it, it returns CF=0 and
> > # sectors = (a reasonable number).  If I run this OS in QEMU it returns
> > CF=1 and # sectors = 0.  How do I get correct BIOS response in QEMU?
> Your OS is calling the BIOS that QEMU provides for the virtual machine
> that your OS is running inside of.  So the first thing to track down is
> what that BIOS is and whether it actually implements INT 0x13.
>
> Dale
The QEMU site says it emulates PC BIOS from the Seabios project.  I 
looked at the Seabios site and it references many sources.  I'm not sure 
how to interpret the info on the Seabios site but they do reference Ralf 
Brown Interrupt List.  RBIL info implies Seabios does not support int 
0x13/ah=0x48.  I can't imagine why Seabios would not support that.  How 
can an OS partition and format a drive if it doesn't know the number of 
sectors?

Bill S.