DVD recording time question

[mwdxer1]

This is the closest Satellite Guys support group to post this question. I hope it is okay.
I have a Toshiba DVD recorder. In recording I always get more time on a DVD + than a DVD - disc. At the 2 hour mode, DVD - will get me about 2 hr and 4 minutes, but the DVD + will get me about 2 hr and 11 minutes. This is on the Verbatim SL discs as well as Fuji SL discs. Any idea why? I have read both carry the same space. Thanks.

 

[dfergie]

I had a Panasonic, but it's been so long I can't remember what recording times I got with it as I used the Ram discs.

 

[harshness]

DVD-R perhaps has more overhead. If there were more recordings, the record times may be closer (or even further apart).

 

[mwdxer1]

DVD-R perhaps has more overhead. If there were more recordings, the record times may be closer (or even further apart).

Can you explain a bit more? Thanks.

 

[harshness]

Can you explain a bit more?

A detailed explanation of why won't change the results.

The two formats probably index the data in significantly different ways (as evidenced by the fact that you don't have to "finalize" a DVD+R). If I had to guess, I'd say that DVD-R has a larger reserve for directories that is largely wasted when there are only two to four files.

Think of it like the differences between computer disc filing systems (FAT, NTFS, HFS, EXT2). Some systems have relatively high overhead while others seem better suited to only a handful of files. In NTFS on a 1TB disc, a file with 850 bytes of data in it takes 4096 of space to store because that's the default block size (very small files house their data in the directory entry).

I recently did an experiment on a directory tree with a lot of files in it on a NAS and discovered that 50GB of storage was holding only 31GB worth of data.

 

[mwdxer1]

A detailed explanation of why won't change the results.

The two formats probably index the data in significantly different ways (as evidenced by the fact that you don't have to "finalize" a DVD+R). If I had to guess, I'd say that DVD-R has a larger reserve for directories that is largely wasted when there are only two to four files.

Think of it like the differences between computer disc filing systems (FAT, NTFS, HFS, EXT2). Some systems have relatively high overhead while others seem better suited to only a handful of files. In NTFS on a 1TB disc, a file with 850 bytes of data in it takes 4096 of space to store because that's the default block size (very small files house their data in the directory entry).

I recently did an experiment on a directory tree with a lot of files in it on a NAS and discovered that 50GB of storage was holding only 31GB worth of data.

Thanks. That makes sense. I never used + DVDs in the past other than DL ones on the computer, so I did not know there was a difference.