Re: How to burn Fedora DVDs to avoid readahead bug?

Rick Stevens wrote:

On Tue, 2007-05-08 at 02:37 -0400, Andre Robatino wrote:

When I burned the Fedora ISOs to CDs, I used cdrecord with padding to avoid the readahead bug - see

http://www.troubleshooters.com/linux/coasterless.htm

for how.  In short, you use something like

cdrecord -v dev=/dev/cdrom -dao -pad padsize=63s FC-6-i386-disc1.iso

It turns out that the same precaution is necessary with DVDs, and until recently I was able to use cdrecord for this, like

cdrecord -v dev=/dev/dvd -dao -pad padsize=63s FC-6-i386-DVD.iso

even though a lot of ugly-looking error messages appeared before the burn commenced. But in the last month or so, instead of burning, cdrecord simply gives up. See

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=233745

I know about growisofs, but unfortunately it's incapable of putting padding on the DVD _after_ the ISO file (I know it has a -pad option, but it just passes it through to mkisofs, which provides padding _inside_ the ISO, which isn't what is needed, and when burning an ISO file it can't be used anyway). I tried once using dd to manually add zero padding after the ISO, but although the resulting DVD passed mediacheck, it failed to boot properly. So it seems that at the moment there's no tool that can reliably burn a DVD and pad it properly. After gradually learning over several years how to reliably burn Fedora ISOs, I don't want to go back to mediacheck hell. As I see it, there are several options:

1) Fix the readahead bug. Unfortunately, we all know that will never happen. No one who's qualified cares enough to do it.

2) Fix cdrecord. The last time I successfully used it was March 29, so some update since then broke it. It's not the kernel, since after booting into the same kernel I was using then, it was still broken.

3) Find some other tool besides cdrecord that can do the necessary padding for DVDs. Are there any?

4) Modify mediacheck. I know that by default mkisofs provides enough padding to protect the files inside the ISO from the readahead bug. But mediacheck is apparently checking the entire ISO, including the padded part at the end after the actual files in it, where the readahead bug occurs. Can it be tweaked to just check up to the end of the last file inside the ISO? And can something similar be done so no errors occur during the actual install either?

All of my FC DVDs have been written with:

	growisofs -dvd-compat -Z /dev/dvd=/path/to/dvd.iso

with nary a glitch (no need for read ahead padding, nada).  Burned on
multiple machines with different DVD writers, readers, etc.  Either I've
been hugely lucky or you've been hugely unlucky.