[syslinux] Syslinux DOS-based installer in FreeDOS

[Gene Cumm]

On May 30, 2014 12:28 AM, <perditionc at gmail.com> wrote:
>
> On Sat, May 24, 2014 at 11:22 PM, H. Peter Anvin <hpa at zytor.com> wrote:
>
> > 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
> >
> >
> Thank you both, for finding the bug and narrowing down to the specific
> calls at fault.
> I have posted a preliminary fix (see
> https://sourceforge.net/p/freedos/bugs/121/ ).

Nice. From an overview standpoint, it certainly looks good. Now for further
testing.

--Gene