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Warning about DVD-R with Pioneer DVR-216D revision 1.09


in libburn i had to work around a nasty pitfall
with DVD-R and sequential DVD-RW on
   Pioneer DVR-216D revision 1.09

If the drive buffer is inquired via READ BUFFER
CAPACITY more than once while it is still in the
process of first filling, then the drive goes
It swallows input data as fast as can be
transmitted and does not become usable until
next power cycle. In case of a built-in drive,
this means system reboot.
The media is afterwards still blank and can
still be used for burning.


cdrecord-2.01.01a64 runs into the same problem
when used with option -v. (Without -v there is
only one READ BUFFER CAPACITY shown by -V.)


growisofs would have the problem if the drive
had a buffer larger than 2 MB (it has 1.5 MB).
I verified this by changing in growisofs.c:
        if (poor_man && (off&63)==0)
        {  float u = get_buffer_stats(ioctl_handle);
        if (poor_man && (off&15)==0)
        {  float u = get_buffer_stats(ioctl_handle);
which caused the madness described above.


wodim -v does not cause madness although -V
shows  several buffer inquiries before the
buffer is full.
My best guess for a reason is its write size of
62 KB, whereas the other programs send 32 KB per
WRITE command.


My workaround in libburn is to inquire the
buffer once and to not inquire it again until
its reported size + 256 KB was transmitted to
the drive.

Have a nice day :)


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