[GLLUG] CD-RW Packet Writing

[Matt Graham]

> At last week's meeting, someone 
> asked about packet writing on optical media.

"Don't bother" would be my advice.  Packet-writing has a lot of overhead and
600M isn't as much data as it used to be.  If you have a few M to transfer,
USB keychain drives typically make more sense than CD-Rs.  If it's more than
will fit on your keychain drive, ISO9660 multisession works just fine and has
less overhead/hassle associated with it.

> Among the other 654 patches in 2.6.9-rc3-mm2 are found: 
>    A big DVD+RW support patch, which includes CDRW packet writing 
> support. 

> This is something I've been awaiting for years and have never understood 
> why it took so long.

Kernel subsystem confusion, probably.  A CD-R* was a read-only device for a
long time, so Joerg Schiling had to have cdrecord work on the generic SCSI
devices.  Joerg has an abrasive personality and has called the SCSI subsystem
a complete mess, which has not endeared him to the kernel hackers, and for
Goddess's sake, don't mention GNU tar to him.  ide-scsi emulation also
confused a lot of people.  And there were other things going on that the
kernel guys thought were more important.  (Hey, you can read UDF, if it's
really important, you can write it with some patches!)

This is pretty much par for the course in kernel-land.  Linus doesn't like
cdfs (patch that allows audio CDs to appear as if they have a filesystem, 1
file per track) so it's never going to be in the vanilla kernel.

> packet-writing CD-RWs is literally the last thing I still use Windows 
> for. 

?  I just wonder why anyone bothers with packet-writing.  k3b has a nice
pointy-clicky interface to multisession ISO9660, and before k3b existed, the
mkisofs/cdrecord commands for multisession were all in the CD-Writing HOWTO
and on groups.google.

> For anyone interested, Peter Osterlund has been updating the (ancient) 
> Jens Axboe packet-writing patch for current kernels at:
>    http://w1.894.telia.com/~u89404340/patches/packet/

Yep, it's been there for at least 2 years for anybody who's ever really needed
it.


-- 
Matt G / Dances With Crows
There is no Darkness in Eternity/But only Light too dim for us to see
"I backed up my brain to tape, but tar says the tape contains no data...."