[syslinux] Syslinux DOS-based installer in FreeDOS

[H. Peter Anvin]

On 05/24/2014 01:58 PM, Ady wrote:
>  
> My guess is that if this was a bug in FreeDOS (as in "something" that 
> has nothing to do with the syslinux.com command) then it would be 
> somehow triggered by other DOS programs trying to write to the MBR. 
> Considering that there are several (open source) DOS programs that 
> are capable of successfully writing to the MBR under FreeDOS, I would 
> tend to think that there is some interaction issue.
>  

There are a few different ways to do this.  I suspect programs like
FDISK use direct BIOS accesses, because they have to also create partitions.

Syslinux uses INT 21, AX=440D, CH=08/48 CL=41/61 which to the best of my
understanding is supposed to read the absolute sectors corresponding to
a target device, and I just verified under MS-DOS 6.22 behaves that way,
and that FreeDOS 1.1 does not -- which by definition means it is a bug
in FreeDOS.

	-hpa