Mailinglist Archive: opensuse-factory (757 mails)

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Re: [opensuse-factory] tagmedia question
  • From: Volker Kuhlmann <hidden@xxxxxxxxxxxxxxx>
  • Date: Tue, 9 May 2006 20:22:45 +1200
  • Message-id: <20060509082245.GC5704@xxxxxxxxxxxxxxx>
> So the current kernel still does read-ahead past the end of the device? I had
> reported that for SuSE 9.0 I think, and the blabla was that I would be using an
> uncertified DVD/CD-RW drive.

While I don't want to argue about kernel developer's knowledge, this
does sound like buck-passing to me. Turning DMA off usually allows to
read a few more blocks, sometimes to the end. But when turning off
read-ahead (hdparm -a0) and suddenly all iso fs blocks become readable,
then my finger points at the kernel, not the drive. This was SuSE 9.2.

> Definitely padding the iso will help as long as noone
> tries raw-reading the iso back.

Ehh, I am reading ISOs back all the time and insist on continuing to do
so. Ignore Eberhard and pad after the ISO when burning. Btw in SuSE 9.2
150 blocks = 300k was not enough padding for DVDs. Of course this
doesn't help with disks already burnt.

> That bug should be fixed in the kernel, and
> exactly there.


I've had Redmond-burnt CDs with 2 empty blocks after the last non-null
block, and 9.2 failed to read the last file on the CD. I doubt this CD
would have been unreadable under the other OS.

It's probably difficult to fix because the kernel block I/O layer
doesn't know anything about isofs (and mustn't - could be reiserfs on
the CD), and the whole CD technology doesn't supply the information of
what the last recorded block is, or something like that.


Volker Kuhlmann is list0570 with the domain in header Please do not CC list postings to me.

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