DVDs session-able?

I assssumed that when I was burning backup info on a DVD-R (as I am so excited to be able to burn folders/projects that exceed a CD) that I would be able to burn some, then burn more etc until I fill the DVD... is this totally wrong?! I was/am able to burn CD's different amounts at a time, as sessions in Toast, (I don't have the newer Toasts.. (when do we ever get to stop buying software, esp when you're like 15 days before a new version releases - how are you supposed to know to wait 15 days?!?)) but can I not burn what were called sessions in Toast for CD's on DVDs? ie today I burn 2.5gigs and in a week or whatever fill the rest of the DVD with 2.1gigs of info? or am I burning whatever I put on that DVD-R and 'trashing' the rest of the space?
I'm on a 1.43ghz ibook w combo CD/DVD writer.

Hi there,

As far as I know there is no deffinative 'format' for multisession DVD's...so it has never really taken off !

Does your iBook support RW DVD's...you could burn a DVD then erase and reburn with the added bits if you see what I mean.

Are you on 10.4 ?

If you are you could create yourself a little Automator workflow to make it easier...

Or you could use Disk Utility to make a "Disk Image" them same size as a blnk DVD...then you add anything you want to back up to the Disk Image...then burn.

Then a week later...add more stuff to the disk image erase the DVD and reburn the Disk Image...keep doing to the Disk Image is full (so will the DVD be) and then start over.

Some backup software such as Retrospect will write 'sessions' when backing up...but this is there own format...

Depending on what your project are (how important !) you could do a backup to DVD-RW then the next day backup to a new DVD-RW then on the next day erase the first disk and backup again...repeat...this way if the hard drive ever fails or if the DVD fails then you will have a backup of the backup...

From what I can see the new version of Toast (7.0) has data spanning, so it may do what you're after I have Toast 6 some where I think...if I get chance I'll download the update and have look.

regards

Ric