View Single Post
Old 8th March 2011, 12:26   #102  |  Link
yetanotherid
Banned
 
Join Date: Apr 2008
Posts: 723
Well I've just finished the world's least scientific study of disc longevity. "Least" because it's a small random sample and I've not really got any idea as to the horrors the discs may have been subjected to since they were burned. All came from the "poor burn" spindle but I've no way of knowing what the quality of each was like when it was originally burned. I thought I'd find older discs (I may have to search the house for them) so these only go back a few years.

One trend which seems to have emerged, all the discs seem to have deteriorated in quality but it would appear the ones which have deteriorated the least are Verbatim.
Admittedly they've all been subjected to wear and tear but what surprised me is this..... I don't keep all the bad burns, only the ones I think should still be usable, so once the quality has dropped too low (say under around 40% according to Nero CD Speed) I throw them away. Anything between 40% and around 90% goes on the "poor burn" spindle, anything above 90%-95% goes into the archive folder.

Running quality tests again today on a random sample of these "poor burn" discs led me to the conclusion that had the burn quality of the discs I tested been as bad originally as they are now I never would have kept any of them in the first place. Therefore they must have deteriorated. Many were so bad I doubted they'd be readable at all. This includes TDK Premium discs, TDK Gold discs (or pretty much anything using CMC MAG dye) Sony, Imation, etc. The brand I checked the most was Verbatim, mainly because there's a lot more of them than other brands, but they do seem to have deteriorated the least. In fact I only found one Verbatim discs which was of such a bad quality I probably would have just thrown it away if it was burned that badly originally. I can't say the Verbatim discs haven't deteriorated (they probably have) but it would appear that it's not as much as all the other brands of disc.

I've posted some rather distressingly "typical" screen shots below. As I said this is the world's least scientific disc longevity test but it makes me wonder what the average person's collection of burned discs must be like, given most people don't run quality tests after burning and most would own discs which have been subjected to similar wear and tear. I'm going to run part 2 of the test later. It'll involve exactly the same random testing, but this time I'm going to pull random samples of discs from the "good burn" folder. Unfortunately 99% of those discs are Verbatim but there's other brands scattered in amongst them. It'll be interesting to see if there's any pattern in quality when testing discs which I know would have been of a good quality when originally burned, and which have led a sheltered life in storage and hardly ever been used.

For the record I checked 1 X Benq disc, 2 x Imation, 1 x No-Name (CMC MAG), 1 x No-Name (Prodisc), 1 x Sony, 4 x TDK Gold, 2 x TDK and 6 x Verbatim. As I said.... hardly scientific.

There was one other interesting result and I'm not sure if it's thrown a spanner into my test results. I only tried it with two of the discs.... mainly because it didn't occur to me to try until I'd almost finished.... after running the quality test on the TDK Premium disc and the No-Name (Prodisc) below with their 0% quality score I tried copying the files from the discs to my hard drive. What surprised me was the same drive I used for running the quality tests (Pioneer 112D) copied every file from the TDK disc in around ten minutes. In fact watching the copying process it appeared to pull all the files off the disc without missing a beat. It copied every file from the No-Name Prodisc as well, although it was obviously struggling towards the end of the disc.
I don't know what to make of that.... whether the drive is a really good reader, whether it's not reporting errors as accurately as I thought it did, or whether the quality of the burn really doesn't have to be anywhere near as perfect as I've assumed it does.....

Benq


Imation


No-Name (Prodisc)


Sony


TDK Gold


TDK Premium


Verbatim (Although I had to test quite a few to find one this bad)

Last edited by yetanotherid; 8th March 2011 at 12:31.
yetanotherid is offline   Reply With Quote