The changing Fedora

[Patrick O'Callaghan]

On Tue, 2013-01-22 at 09:45 -0700, Greg Woods wrote:
> On Tue, 2013-01-22 at 15:29 +0000, Patrick O'Callaghan wrote:
> > On Tue, 2013-01-22 at 08:02 -0700, Greg Woods wrote:
> >  The game CD has some stuff written
> > > beyond the "end" of the disc.
> 
> > I would have thought that correct emulation would allow those same
> > low-level calls in a VM. AFAIK the guest system can read the whole CD as
> > a raw device (assuming appropriate privileges).
> 
> The trick is in defining "correct" emulation and "the whole CD". If the
> entire ISO image can be read, isn't that the whole CD? Well it is,
> unless you come across this kind of trickery. So it's not hard to
> imagine that a hypervisor emulator might not implement the ability to
> read blocks that are technically beyond the end of the disc.

So are you talking about 1) the actual physical CD, or 2) an ISO image
of the CD? I presumed the former, in which case there *should* be no
difference (and if there is, then the VM's emulation is incomplete).
OTOH if it's an ISO image, then all bets are off; for one thing whatever
software created the image may not have tried to read the entire
physical medium but just the filesystems it found there, and for another
(probably more relevant in this case) some copy-protection schemes use
deliberately damaged blocks so that normal s/w will get read errors
which an ISO image cannot reproduce.

> > One reason for some games not working is that they require a better
> > graphics card than the one emulated by the VM.
> 
> True, however in at least one case I get complaints like "please use the
> ORIGINAL CD" when trying to load the game in a VM, even when I *did*
> have the original CD. There is obviously some kind of copy protection
> going on that doesn't work properly from within a VM.

See option (1) above.

poc