Re: Is dvd-r not supported in cdrecord?
Hi,
Bill Davidsen:
> My assumption, as I posted earlier, is that it is trying to mount media of
> any type it understands. To guess the media type the first sector is read.
> This requires a seek to sector zero and a read, leaving the burner at a
> location which has already been written.
The mere seek aspect is not to blame.
Each WRITE command carries its target block
address. We have to increment it in sync with
the written data amount or else we get an error.
Nevertheless, the sequential write models of
CD and DVD-R[W] get disturbed by unexpected
other commands. One may inquire the drive state
but not much more.
It might be that the problem gets triggered
by the Linux device driver and not directly
by hald. Me and Eduard Bloch once made
experiments where our own programs were able
to spoil burn runs by simply opening the drive
device file O_RDONLY. One needed about a dozen
tries for one failure.
My opinion:
A sequential burn run on CD or DVD-minus needs
the drive exclusively. Anything else is not safe.
This exclusivity must be negotiated without
successfully opening the device file.
> I think growisofs uses O_EXCL and I don't recall any
> behavior after burning which made me unhappy.
You need DVD-R or unformatted DVD-RW to have
a chance to see the problem with growisofs.
You probably need several tries to get bitten
- if ever.
With DVD+R there seems to be no such problem.
For cost reasons i never tried to spoil a BD-R
burn run. But they are very similar to DVD+R.
DVD+RW, formatted DVD-RW, DVD-RAM, BD-RE are
surely safe from hald. (Formatted CD-RW too,
i would assume.)
Have a nice day :)
Thomas
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