UDF Filesystem as replacement to FAT*, ISO9660, and other Filesystems.

[Phillip Susi]

That is not accurate; I will have to queue a patch to fix that 
documentation.  DVD+RW drives are required to support sector level 
writes in the firmware, so directly mounting a udf filesystem on such a 
disk via the standard device works.  For cd-rw media, the disc must be 
formatted for packet write mode, and then the drive can only write in 
whole packets, so to support writing to individual sectors, the pktcdvd 
driver must be used to coalesce multiple writes into an entire packet, 
or read the remaining parts of the packet to merge the writes with, then 
write the full packet.

Rolf Kutz wrote:
> * Quoting Phillip Susi (psusi at cfl.rr.com):
> 
>> a hard disk.  Also Windows does not contain native write support for 
>> optical media; you have to install third party packet writing software.
> 
> Neither does Linux. 
> Documentation/filesystems/udf.txt:
> 
> |  Write support requires a block driver which
> |  supports writing. The current scsi and ide cdrom
> |  drivers do not support writing.
> 
> - Rolf
>