Packet Writing

Writing to optical media is all well and good but clearly the future lies in using optical disks as one would a hard drive, or a floppy, or flash drive - packet writing.

So I set up packet writing on Debian Etch using udftools and formatting a DVD+RW disk in udf (?universal disk format).

Imagine my disappointment when it worked, but very, very badly and strangely; the drive frequently going mad and necessitating unclean shutdowns.

Any road up, the problem may have been fixed, at least partly and because my error was, it seems to me, easy to make and difficult to see you've made it, it seems worth describing:

I had failed to understand that packet writing only involves the udf file format incidentally. It is easy to imagine some system for packet writing that would involve vfat, for example.

So when the DVD is used in the ordinary way it is just mounted read only something like:

mount -t udf -o ro /dev/sr0 /media/dvd0 (where sr0 is the device name of the DVD-drive in the normal way).

But when you're packet writing you should mount the packet writing device:

mount -t udf -o rw,noatime /dev/pktcdvd/0 /media/dvd0

What I had been doing was using the first mount (with rw when needed) in both circumstances.

This was so difficult to see as an error because the thing will packet write, to a limited extent, in this mode.