Fedora Core 5 common issues and bugs

[Peter Jones]

On Wed, 2006-03-29 at 19:51 +0200, Rob van Nieuwkerk wrote:

> 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.

This will almost always get you the wrong result.  At the very least,
you need 'bs=2048 count="$(($(isosize /dev/cdrom) / 2048))"' with that,
or you wind up doing md5sum on completely bogus data with some media.

But as it turns out, that fails the exact same way that mediacheck does.

> I really never understood why there never has been any trivial
> work-around on the FC images for this very annoying problem.

dd does read(2) just like mediacheck does.  There isn't some spooky
magic here.  It fails in exactly the same ways for exactly the same
reasons.

-- 
  Peter