Can PIONEER DVD-RW DVR-127D burn DL disks?

You should be able to write +R DL as indicated (with a firmware update). (I have had issues using DVD +R DLs in the past. The only ones which have consistently worked are Verbatim ones).

DVD-Write: -R, -RW, +R, +RW, +R DL

This should also help you verify it.

http://eshop.macsales.com/Descriptions/apldvr109.html

ROM - Read Only Media

DL - Dual Layer or Double Layer (the manufacturing process for the two is slightly different, but it has no impact on your capabilities).

DVDs which can be written have variants. +R and -R, -RW and +RW.

The +R and -R versions have Single and Dual/Double layer variants and go from 4.3+ GB to 9 GB.

The -RW and +RW do not have dual layer variants AFAIK. The RW are write-many times media.

*3 separately stated the Dual- vs Double- layer DVDs (due to manufacturing differences) separately. Sometimes a notation like

DVD +/- R DL is used to specify DVD -R DL and DVD +R DL as a single combination.

The Firmware upgrade and the appropriate OS versions should help you write DL media.

If you are curious read http://en.wikipedia.org/wiki/Dvd

One thing I should add is that DVD also have a Double-Side variant, which allows both top and bottom surfaces which essentially could allow 18GB, but they were never available in consumer space, but commercial DVD-Video started using one side for full-screen and the second side for widescreen versions. The soundtracks may also vary on either side.

I suggest you try a good brand and worst case it will be a good coffee coaster. 😉

My old Memorex RWs (from almost 15+ years ago are still working). On the WiKi page, you can see the DVD-18 which is roughly 16GB.

Consumer grade DVD writers have a tough time handling DS DL (Double Side + Double Layer).