On Mon, 31 Jul 2000, Bart Oldeman wrote:
> On Fri, 28 Jul 2000, Alistair MacDonald wrote:
>
> > On Thu, 27 Jul 2000, Ralph Alvy wrote:
> >
> > > Will dosemu be able to access partitions beyond the 8gb barrier? Normal DOS
> > > can't. I assume it will be able to, since it's relying on linux to do that
> > > work for it.
> >
> > If you mean partitions that *start*/*finish* beyond the barrier then, if
> > Linux/your system/etc. supports them, you should be able to. If you mean
> > partitions whose *size* breaks the 8Gb barrier then probably not, because
> > we still have to emulate the FAT.
>
> I've researched it a bit further, and the 8Gb barrier is because of the
> BIOS. The BIOS (to be precisely interrupt 13h) has a limitation of
> 1024 cylinders, 256 heads and 63 sectors/track. With 512 bytes/sector this
> gives 1024*256*63*512=8,455,716,864 bytes.
> See the Large Disk HOWTO for more details.
>
> The emulated int13 in DOSEmu is no exception to this rule, except that the
The extended BIOS call that uses 64bit block numbers is implemented in
DOSEMU, so there should be no problem accessing large partitions. At least
not more than usual.
My experience with large lredir'ed filesystems (some GB) is that it
depends on the apps you're running. Some can't cope with filesystem
sizes >2GB, some can't handle filesystems with >2GB *free* space, some
just don't work at all.
Apps that don't care about fs size at all should always work. But quite a
lot like to check if there is enough free space left on the disk before
creating a file or such.
> initial bootdir : probably 2GB. This is the AFAIK only place where an
> emulated (read-only) FAT - a FAT16 - is used.
It doesn't really matter. The emulated fs is about 400MB in size but
that's not really important as you'll need just the system files and
they're typically in the root dir (the root dir is placed first into the
emulated FAT fs).
Steffen
