[syslinux] Possible memdisk issue
Ady
ady-sf at hotmail.com
Wed Jul 9 17:25:02 PDT 2014
> On 07/09/2014 04:00 PM, H. Peter Anvin wrote:
> >
> > So this would seem consistent that this is the FAT12/FAT16 boundary that
> > breaks stuff. Perhaps FreeDOS has a problem with FAT16 on floppies?
>
> If I understand things correctly, a bootable floppy has two key pieces
> of executable code: the 512-byte boot sector, and the kernel loaded by
> that boot sector.
>
> The kernel can be large, and thus could perhaps in principle auto-detect
> FAT12, FAT16, FAT32, whereas the boot sector code is limited to around
> 460 bytes (as file system config data is also stored in there), so
> perhaps that's not enough space for auto-detection code? Perhaps there
> simply have to be 3 different boot sectors, depending on whether you've
> got FAT12, FAT16, or FAT32? That would explain what's happening here:
> newmkfloppyimg called mkdosfs, who made a different file system, yet
> newmkfloppyimg copied over the old file system's boot sector...
>
> Does anyone know whether it is possible to have a "universal" boot
> sector and "universal" kernel? Then if one starts with a base floppy
> image containing those, then newmkfloppyimg should create something
> bootable no matter what size is specified.
>
> Alex
We might be getting off-topic.
Is there a FAT{12,16} superfloppy image that MEMDISK is currently
unable to boot?
When building a FAT image, containing the _latest_ FreeDOS kernel, by
using the _latest_ mtools (and/or _latest_ dosfstools), can MEMDISK
load it correctly?
I wouldn't be so surprised to have some kind of problem with an image
built by an old version of mtools / dosfstools containing an old
FreeDOS kernel.
As I mentioned before, I have used MEMDISK with bigger floppy images.
If there is a specific set of FAT parameters that triggers a problem
for MEMDISK, I would like to hear about them.
Regards,
Ady.
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