How much overhead per session?

[furry_beans]

Just curious about how much "overhead" there is when creating a new session. For example, how much space is used for lead-in and lead-out.

I ask, because I have some files I wish to burn to a DVD+R disc, but I don't have enough to fill the entire disc. I'd like to add more at a later date if possible?

Nero 6 warns me that multisession discs aren't supported by some DVD-ROM drives, and also that only Windows XP supports them. Is this true? I'm using Windows 2000. Would I run into problems, even if I used the DVDRW drive to read the discs?

TIA

[aggies11]

Not actually sure about that.

But if you have a RW around, try a few tests!

Burn a few sessions. See if win2k handles them okay.

Possibly try burning a series of 500MB sessions. Check if the reported/actual size is off by alot (to measure leadout).


Can't do any harm since they are rewritable discs

Aggies

[furry_beans]

Good idea. I just wondered if anyone *knew* before I start messing with my RW discs (s'pose I can always use the one that came with the drive!)

*UPDATE*

Well, I can confirm that it all seems to work, and much better than expected.

Nero reports the file system overhead as 300 KB approx. (this is only for a couple of files, but still...)

The Disc Info option pops up a list of sessions, but even though I have done 2 separate sets of files, they show up as a single session, which is a good thing I assume.

And Windows 2000 has no problem seeing both "sessions".

However, I do have to eject and re-insert the disc after burning for some reason...


*UPDATE 2*

Windows 2000 seems to get a little confused with multi-session DVD discs, and will only show the capacity and used size as that of the last session...

[garryheather]

I think in the CD-R domain it's a Meg or two per session plus something like 5M for the first one to allow lead-in / out, but I don't know the approximate figures.

I doubt DVD-/+R is much different. The procedure isn't all that different either.

[furry_beans]

Yeah, I thought it'd be similar to CD-Rs. I just heard somewhere that the overhead was about 200 MB :/ (because you can't fit 4700 MB on a DVD or something - maybe because 1 GB isn't 1000 MB?)

[aggies11]

Woh, heh, overhead should definitely not be *that* much

DVD's sizes and hard-drives are both listed incorrectly mainly due to marketing reasons. For them, one GB is considered 1 Billion bytes. When in reality 1GB = 1073741824 Bytes (1GB = 1024MB, 1MB = 1024KB, 1KB = 1024 bytes ...) So when you list something using *their* math, they always turn out to be a bit larger...

So each DVD/Harddrive GB is short by about 70MB. The 4.7 actually works out to be around 330MB short, leading to an actual capacity of 4.37GB or 4480MB

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