A tech enthusiast has shared his DVD rewritable endurance findings. In an extensive blog post, Dr. Gough Lui describes his test methodology and discusses the results in detail. Sadly, the best DVD rewritables from the six months of tests Dr. Gough completed - TDK branded discs - are no longer being manufactured.
Dr. Gough first explains how he managed to run the tests, which ran for a solid half-year. The test process was automated using a Python script, as even testing one DVD over 1,000 cycles would take ~21 days. The script also recorded results, with screenshots included.
An as-new condition Lite-On iHAS120 6 was the drive model to run the tests. In its favor, it supports error scanning with jitter, and the doctor had two spares. After some initial setup steps, it was decided to use two of these drives in parallel so that the test suite wouldn’t use up a whole year…
Each test loop included a disc write, then data verification, a transfer rate test (RTT), a quality scan to check for PI/PO errors and jitter, and an erase cycle. This loop would continue until verification failure. “The criterion for disc failure is set as the first verification run that fails due to an error,” the doctor wrote. The resulting figure is accurate ±3 cycles.
Dr. Gough admits there were limitations to the experiment and methodology. Firstly, the life cycle result “is valid only for the combination of burner and disc tested,” says the doctor. Moreover, limited resources and time meant that only a few DVD samples were put through the test regime (as charted below). It is made clear that each row of the test summary is indicative of a single sample of each DVD rewritable available. Another fly in the test ointment was that “some discs return very poor error scan values but remain readable and vice-versa.”
Dr. Gough then goes through each of the sample disks, sharing plenty of commentary on the finer points of the results and how they aligned with expectations. The source also includes an interesting side-quest, where the good doctor uses a Nu Tech DDW-082 drive, which could purportedly revive rewritables using a function called ‘DC Erase.’
The TDK 2x DVD-RW (TDK502sakuM3) was the only disc to survive beyond 1,000 cycles of the testing (or 2,000 if you count the write and erase separately). It was clearly the top performer. This disc led the charge for the DVD-RW camp against the DVD+RW side.
Also, on the – vs + topic, it was interesting to see the former dominate the top of the table. There are so many reasons this may be the case in a test of limited scope like this. For example, the ‘minus’ media might just work a bit better with this Lite-On drive hardware/firmware than ‘plus’ media. Or the triumphant ‘minus’ rewritables had some benefits with respect to degradation of the phase layer material.
As for current stocks of DVD-RW and DVD+RW discs, only Verbatim, Maxell, Ridata, and SmartBuy-branded rewritable media are available at Amazon.
