Exactly which white papers have you read to back up the assertion that plus media has better archival properties?
I never said that I referred to ANY "white paper".
I am primarily relying on my own experience and testing. While I usually prefer to use DVD+R in my work, there are the occasional requests for DVD-R. Even though I use the same high quality DVD media the DVD-Rs experience a higher failure rate over time in use.
I have generally considered the superiority of DVD+R to be fairly well-established. This probably doesn't qualify as a “white paper” but below are some of the facts regarding the newer DVD+R standard.
(My apologies for the length, I tried to edit it down.)
"DVD-R
*** for data preservation for three reasons: inferior error correction, inferior ‘wobble’ tracking, and the fact its data writing methods look like an un-needed halfway point between CD-R and DVD+R."
"On DVD-R, they tried to solve the problem with something called ‘pre-pits’ where spikes in the amplitude of the wobble appear due to pits fully out of phase with the rest of the track"
"Unfortunately, this method as one flaw: due to electric noise in the laser pickup, it would be very easy to miss the pre-pit (or read one that wasn’t actually there) if the disc were damaged or spun at fast speeds. The time to read a pre-pit is 1T (roughly .0000000038th of a second), which even for a computer can be easy to miss. DVD-R traded hard to track frequency changes for hard to read wobble-encoded data."
"On a DVD+R, however, they came up with a much better method. Instead of changing the frequency of the wobble, or causing amplitude spikes in the wobble, they use complete phase changes. Where CD-R’s and DVD-R’s methods make you choose between either easy wobble tracking or easy ATIP reading, DVD+R’s method makes it very easy to track the wobble, and also very easy to encode data into the wobble. DVD+R’s method is called ADIP (ADdress In Pre-groove), which uses a phase change method."
"The DVD-R specification states that for every 192 bits, 64 of them are not protected under any scheme, 24 of them are protected by 24 bits of parity, and the last 56 bits are protected by another 24 bits of parity. This weird (to put it mildly) scheme allows you to easily scramble or lose 25% of the data that is required to read your disk! This information is almost more important than the actual data burned on the disc itself.
The DVD+R specification, however, states that for every 204 bits of information, it is split into four blocks of 52 bits containing 1 sync bit to prevent misreading because of phase changes, 31 bits of data, and a 20 bit parity (that protects all 32 bits of data)."
"In addition to the optimum power control profiles, DVD+R also gives four times more scratch space for the drive to calibrate the laser on; more space can only improve the calibration quality. So, in short, DVD+R media exists to simply produce better burns and protect your data better."
Full article:
http://adterrasperaspera.com/blog/2006/10/30/how-to-choose-cddvd-archival-media
