DVD+R is it rewriteable?

[gordon55y]

Hi,
I wonder if someone can clarify if DVD+R is rewriteable?
I am able to edit files on my DVD+R (phillips and maxell).
I thought that DVD+R cannot be rewritten?

Is it possible that the DVD recorder leaves a bit unwritten for each filename,
then later if it needs to delete/change that file, it writes that bit indicating a null file?

The following indicates DVD+R are not rewriteable:
>Similar to CD-Recordable (CD-R), DVD-R and DVD+R discs are write-once incorporating a dye
>recording layer to which information is irreversibly written by means of a laser heating and altering
>it to create a pattern of marks mimicking the pits of a prerecorded (pressed/molded) DVD. DVD-RW
>and DVD+RW, on the other hand, closely resemble CD-ReWritable (CD-RW) by employing a
>phase-change recording layer that can be repeatedly changed and restored by the writing laser
>(approximately 1000 times).

thanks,
gordon

[tomlee59]

It's a write-once medium. While space remains, you can append to it or "displace" earlier burns (if you are enabling a multisession-disc), but you can't actually edit what was already written.

That said, the most recent session is often the only thing visible to an OS. To get to the older session(s) requires additional work. Given the cheapness of media, and the hassle of supporting multisession burns (just search this forum for ample evidence of the hassle factor), writing as disc-at-once is strongly favored by most folks. If you really need the full flexibility of multiple read/write, just get yourself a couple DVD-R/W discs.

[gordon55y]

tomlee59,
Thanks.
I wonder how this implemented, given that it cannot rewrite.
If it finds duplicate file names, does it get the one with the latest time stamp?

thanks,
gordon

[tomlee59]

That's basically right. Each session is accompanied by its own directory. So if a file has been updated, the new directory will contain a pointer to the latest version of that file. If not, the new directory will continue to point to the last version. At least, that's what's supposed to happen.

[gordon55y]

tomlee59,
Thanks again.
By the way, I had purchased some DVD+RWs.
And I was using one as backup for a small directory.
I rewrote the directory on the DVD several times, when I noticed that it
was not DVD+RW, but was DVD+R.
That caused me to scratch my head as I could not figure how
it could overwrite the original directory.
I will get some DVD+RWs next time at store.
But, this seems to be a good solution for now as I have no
multisession problems and it is a small amount of data.
Just another backup if my flash drive has problems.

thanks,
gordon

[jman98]

I will get some DVD+RWs next time at store.
But, this seems to be a good solution for now as I have no
multisession problems and it is a small amount of data.
Just another backup if my flash drive has problems.

thanks,
gordon

You need to be warned about RW media. It was never designed for long term storage and the discs can sometimes go bad much earlier than they are supposed to. I think they are rated at something like 10000 re-writes but I've seen discs get nutso after only 1 write. That's unusual, but I've seen it. Even if the disc doesn't go bad, the disc material is made to be re-writable, so it tends to destruct with time. What that means is that if you store an RW disc, eventually it will go bad and be unreadable even under the best of conditions. If you really care about backing up this data reliably, I'd suggest buying another flash drive. If you must use RW media, I strongly recommend that you buy Verbatim.

[gordon55y]

jman98,
thanks,
gordon