[Bug 601092] [NEW] 64k block size for BD-R write

[Stuart R Balfour]

Public bug reported:

Binary package hint: dvd+rw-tools

dvd+rw-tools-7.1-6 kubuntu 10.04

Currently,. we do not do 64k writes to BD-R media (we do DVD_BLOCK or 32K writes).
_64k is set at line 283 in file growisofs_mmc.cpp, but not used.  There's a cryptic comment
on line 646 in the same file which suggests some issues in this area:

        sync_cache:
            // should I check if lba+nbl is multiple of 64K in BD case?

The actual block write is in poor_mans_pwrite64() at line 527 of growisofs_mmc.cpp, and
block size of 32K is enforced at entry to that procedure:

       if (foff&0x7fff || size&0x7fff)   // 32K block size
        return (errno=EINVAL,-1);

The smallest writable unit on BD-R is 64K, so I could see issues if there's (half the time) an
odd number of 32K blocks in the device cache.  There could also be speed issues if the device 
cache is ever actually waiting on the host.  This is a piece of incomplete implementation that
needs to get done.  HD-DVD also has 64Kb block size,  so it's impacted too, if it matters.

** Affects: dvd+rw-tools (Ubuntu)
     Importance: Undecided
         Status: New

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64k block size for BD-R write
https://bugs.launchpad.net/bugs/601092
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