Fedora Core 5 common issues and bugs

[Rob van Nieuwkerk]

On Wed, 29 Mar 2006 05:49:13 -0500
Alan Cox <alan at redhat.com> wrote:

Hi,

> On Tue, Mar 28, 2006 at 02:31:19PM -0800, Schlaegel wrote:
> > This presents the obvious question: why don't we just check the iso on
> > the media instead of the media itself, and thus remove this long
> > standing problem.
> 
> If we wanted to do that we would need to do it by walking the mounted iso
> file system. The moment we deal with the raw device the kernel starts treating
> it as a device not a file system so we get readehead into the twilight zone.
> 
> However I'm glad you asked because you've made me realise we may have the bits
> to deal with this as of FC4/5. Specifically we could use the device mapper to
> create an ISO sized mapping of the relevant chunk of the CD and check that...
> 
> That might just work

Sure.  Or something like this:

	dd conv=idirect if=/dev/cdrom count=right_number | sha1sum

And if the dd used on the FC ISO does not support the O_DIRECT feature,
just add it.  Or write a completely trivial 10 line C program that
does the same.

I really never understood why there never has been any trivial
work-around on the FC images for this very annoying problem.
This has been going on for many releases now .. :-(

	greetings,
	Rob van Nieuwkerk