New standard proposal

[Derek Foreman]

On Sat, 27 Sep 2003, Carlos [ISO-8859-1] Perelló Marín wrote:
> El vie, 26-09-2003 a las 22:36, Derek Foreman escribió:
> > On Fri, 26 Sep 2003, Carlos [ISO-8859-1] Perell Marn wrote:
> > 
> > > El vie, 26-09-2003 a las 04:45, Derek Foreman escribi:
> > > > On Fri, 26 Sep 2003, Carlos [ISO-8859-1] Perell Marn wrote:
> > > 
> > > Backing up a disc?
> > 
> > Making a copy of a cd.  This also has to be done with the disc unmounted.
> 
> Hmmmm, I don't see why it should be unmounted :-?

Things like El Torito boot images don't show up in the filesystem, so to 
make a bootable backup things get a little complicated.

> > Which ioctl?  I'd like to see how my drive reacts to it.
> 
> Just look at this:
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/0202.0/att-0603/01-cd_poll.c

Thanks

Unfortunately, it doesn't work on my machine (linux kernel 2.6.0-test5).  

AFAICT, the command was introduced in MMC2, yet two of my 4 drives don't 
support it at all.  (so you'll need a different detection method for a 
lot of drives)

The other two drives accept the command, but the command's buffer comes 
back still full of 0s.  This appears to be a kernel bug, since sending the 
same command with SG_IO behaves as expected.  I've reported this on the 
linux kernel mailing list.