Re: Need help creating CDs that will pass mediacheck

From: D. Hugh Redelmeier (hugh_at_mimosa.com)
Date: 03/12/05

  • Next message: Richard Schmitt: "FC2 cannot access networked printer" 
    Date: Fri, 11 Mar 2005 22:39:06 -0500 (EST)
To: Dan Trobridge <linuxddt@gmail.com>, For users of Fedora Core releases <fedora-list@redhat.com>

    | From: Dan Trobridge <linuxddt@gmail.com>

    | Still no resolution. I have been able
    | to get disc1 to pass media check, but no others.

    I suspect that you are having another manifestation of the problem I just
    posted:
      https://www.redhat.com/archives/fedora-list/2005-March/msg02774.html

    I have hit this problem in several different ways with 2.6 kernels.
    Grrr.

    Here's a crude solution that has worked for me: pad the .iso by adding
    a bunch of bytes at the end. Those bytes won't influence the ISO-9660
    file system, but will allow the goofy device driver to read ahead past
    the end of the file system without getting an I/O error.

    How much padding? I used a couple of megabytes of zeros, if I
    remember correctly, but I now think that I know the magic minimum
    number: 33 * 2k. This is the length of the reads that were failing
    (see my previous message) so it ought to be a bound on the amount of
    spurious readahead. It might be the case that the 33 can very under
    some conditions -- I don't know where it comes from and I'm too lazy
    to read the driver code at the moment.

    How can you pad the .iso?

    Method 1 (untested):
            dd if=/dev/zero bs=2048 count=33 >>file.iso

    Method 2 (untested):
            When burning with cdrecord, add the parameter:
                    padsize=33s
            (I don't actually know if a sector, in cdrecord's terminology
            is 2048 bytes; the manpage suggests so.)

    I find it interesting the the cdrecord(1) manpage, in its description
    of the padsize option, says:

        Use this option if your CD-drive is not able to read the last
        sectors of a track or if you want to be able to read the CD on a
        Linux system with the ISO-9660 filesystem read ahead bug.

    If you do test this, please report back whether it worked or not.
    Please cc it to me personally since I don't read this list regularly. 

    -- 
fedora-list mailing list
fedora-list@redhat.com
To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
  • Next message: Richard Schmitt: "FC2 cannot access networked printer"

    Relevant Pages

    • Re: Manipulable Isos?
      ... The problem with most ISO-editing utilities is that they do ... not take into account empty space within a file system. ... system entirely - CDFS or UFS - and do not depend on a fixed partition size. ... ISO is an exact copy of a FAT/NTFS partition, and both of these file systems ...
      (microsoft.public.windowsxp.embedded)
    • Re: Fedora 8 64-bit Athlon Install- Cant find CD/DVD Drives?
      ... an iso ... Although I find it annoying anaconda works this way, I have failed to file an enhancement request on bz, otherwise it would be nice to be able to point it to the Everything directory in the ext3 file system on the same hard drive. ... I tend to do my installs by booting with the rescue cd and pointing it to the DVD iso on a USB hard drive, because on some machines I do not have DVD drives, so I know what you want to do works. ... Crane Division, Naval Surface Warfare Center ...
      (Fedora)
    • Re: Burn from VOB files?
      ... in article <Re: Burn from VOB files?>, ... Is it normal that in some circumstances a DVD could not be opened ... Well, .iso files aren't called ISO files for nothing, you know. ... Or the UDF 1.02 file system used on a DVD-Video disc. ...
      (rec.video.desktop)
    • Re: VCD not readable under 2.6.18
      ... ones for philips short lived interactive stuff) have an ISO file system ... so a VCD disk can appear mountable and ... Perhaps I confuse things with SVCDs, but the ISO part *should* actually be ...
      (Linux-Kernel)