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Say Goodbye To Your CD-Rs In Two Years?
Little Hamster writes "According to an article on cdfreaks.com, a test done by the Dutch PC-Active magazine showed that among 30 different CD-R brands tested, a lot of them were already unreadable after twenty months. This is shocking, and makes me wonder how should I backup my data, photo and music collection."
...and I have heard this, too! all the *not-illegal* backups of my audio cds that I listen to in my car are damages within 1 month or so. This, despite keeping them in a cd wallet :)
Of course, since cds come cheap, I dont mind throwing away the scratched cd and burning a new one. But what about the environmental cost? 3 -01-13-ct-cdcare.html
btw: I found a decent link for taking care of cds:
http://www.aarp.org/computers-howto/Articles/a200
>> "Two words: Taiyo Yuden"
I've bought nothing but Taiyo Yuden discs for the past 2 years, and have the learned the hard way that they aren't any better. Many discs that I've burned over the past 2 years have become unreadable in as little as 6 months. These discs were stored in jewel cases, in a drawer, and handled carefully (not used as a frisbee or coaster).
I've even tried burning at lower speeds, (i.e., burning at 16x even though the discs are supposed to support 32 or 48x) thinking that maybe this would give better stability, but no such luck.
The cost of CR-Rs has dropped enormously over the past couple of years, to the point where even "premium" brands like Taiyo Yuden can be had for 30 cents (or less). And now we see why -- just like hard drives, the decrease in price is more the result of a reduction in quality than an increase in technology.
Ahhh, any veteran of the Commodore 1541 floppy drive can tell you what this is: alignment errors. You see, the head is moved using these little step-motors. With use, the motors drift out of alignment, meaning the head moves somewhat less (or more) per "kick" than it's supposed to. As long as it's the same motor, that error occurs on every operation, so there's no net effect. (That is, sure, the data's in the wrong place. But during read-out, the head will seek to the (same) wrong place. So no error.) But move that disk to another machine, whose step-motor has a different alignment, and BAM! read errors.
Fans of the C1541 will remember what happens when that drive found an alignment error: CLACKETY-CLACKETY-CLACKETY-CLACKETY-CLACKETY-CLAC
The Mongrel Dogs Who Teach
I don't consider a backup copy kept within 3 yards of the original copy to be a real backup. Afterall, the point of a backup copy is to survive whatever clamity may befall the original copy.
So please, don't call an HD that is in the same computer, or even the same server rack, your backup. However, a network connected machine on the other side of your building will do just fine.
Do you remember science class where they told you a measurement wasn't correct unless it included a +/- error estimate?
Every CD burner (like every real-world device) has a certain amount of error. The device decides to turn the laser on or off, and there is a delay before the laser turns on or off. This small delay varies with heat and other factors within the device and varies with the component tolerances from device to device.
This error rate is over time, not distance. So, if the CD is rotating slower, it doesn't move as far during the error period. This results in a burn which is closer to perfect, that is it has less error distance than a higher speed burn.
Then there is the completeness of the burn; with a brand new good quality drive it shouldn't matter, but how many of you have a brand new plextor?
And of course there's also the CD media. If you bought the 10 cent bulk discs and expected them to last, shame on you. I record at slow speed to the old dark-blue verbatims whenever I can, and after 7 years I havn't lost data yet.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.
Did you ever look into CD-RWs?
They are a phase-change medium, either the substrate is crystalline or it is amorphous. Thats not something that's likely to change with time or degrade like an organic dye.
Starman97@Gmail.com (bring it on spammers)
Why does every porn joke get instantly rated "5, Funny"?
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Well, give it up. What brands have you used that are fine, or more importantly, what brands have failed for you? Here's my experience:
Lesson 1: Never get a CD-R w/o any printing on it. I got some (TDK, I think) that were just silver on the top, no branding or anything, and they burned just fine, but I found out later they could be scratched VERY easily. Scratched on the top, mind you. Apparently there was no protective layer over the foil, and you could just scratch it right off. I think they were meant to be printed on by some kind of CD printer.
My TDK's that I burned 2 years ago with the white surface (w/ branding) seem to be perfectly fine though. I also don't seem to have any problem with any imations that are as old.
I have one 2-year-old CD in which the foil appears to be harboring some kind of fungus. The brand is "K Hypermedia," I think I got it for free or really cheap. You probably get what you pay for. But the "fungus" is only on part of the edge, so it still plays fine. I have a handful of others of the same brand, which look okay.
disclaimer: I take semi-good to pretty-bad care of my CDs. They are routinely left out on the counter, desk, or wherever, and sometimes stacked in tall piles, when I don't feel like looking for the matching packaging.
c-hack.com |
Yes, but the original poster is also corerct, floppies bought today are total crap compared to years ago. Every floppy disk I've bought in the last few years have all been unreliable at best, but floppies I bought 10 years old still work perfectly.
Are printers and scanners good enough to make it worthwhile? I don't know. I haven't run any tests and I don't even have a good feel for how many bits you can print on a square millimetre of paper and scan back reliably.
But let's pretend we can print and resolve three pixels per millimetre and 3 levels each of cyan, magenta, and yellow per pixel, and that we're using A4 paper with 10mm margins.
bash> bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'.
ppmm=3
bpc=3
bpp=3*bpc
margin=10
width=210-margin*2
height=297-margin*2
bytes_per_page=width * height * ppmm^2 * bpp / 8
bytes_per_page
532878
bytes_per_page/1024
520
Damn, just 520k for a whole lot of trouble, paper, and ink.
But, as I say, I don't have a good feel for what bpmm and bpp really are. Does anyone know? Has anyone heard of any attempts to actually do something like this?
Fuck the system? Nah, you might catch something.
That article is like those tv news ads, like the one from Simpsons where Kent Brockman said: "A leading brand of cola causes cancer, but we won't tell you which one till you watch the show!"
Well, where is the list of CD-R's that will go bad? I couldnt find it on the link, anyone have a quick list?
Here on Slashdot there are many things that divide us, emacs vs. vi, SuSE vs. Debian, the best Dr. Who, all sorts of geeky crap. There is one thing that unites us all- our love of pornography.
-Barry
Why is everyone surprised? The only means of data storage that has been tested to last 100+ years is to write it out to paper. For extremely critical stuff, it's typically printed in a small font on acid-free paper, then stored in a climate-controlled vault.
Programming can be fun again. Film at 11.
which is a completely ridiculous notion. Well no, let's not be so aggressive, it's not COMPLETELY ridiculous. But if that reasoning was all true, if the laser had the time to burn a pit normally at 1x, then that time would be divided by N at Nx speed (well not exactly, but that's beyond my scope), and the pit would be N times "weaker".
So of course, the power of the laser is increased to palliate this effect.
So in an perfect world, the laser power would be increased 32 times when you increased the speed 32 times, thus making the same pits as if you burned in 1x.
Now this is only taking into account laser power when burning at higher speeds. Thing is, there can be lots of other problems when burning at higher speed, any minuscule glitch in laser power, rotation speed, laser position, anything can cause a problem. Of course most problems are corrected, and those that pass aren't fatal. But with age, the organic compound on which your data is written deteriorates, as any organic compound would, and the errors get worse.
Misleading titles? Inflammatory blurbs? Keep in mind that Slashdot is a tabloid.
There is one thing that unites us all- our love of pornography.
What a silly thing to say. Taking it seriously for a moment - There are lots of people who disapprove of pornography, for one reason or another. The political left (feminism) considers it exploitative, the political right (conservative religious) consider it amoral, and women (even geek women) don't tend to be consumers of pornography. Since Slashdot certainly has its share of political left, right, and women, it's easy to see that no one thing will EVER unite ALL Slashdot readers.
That being said, posts about pornography don't get modded up to +5 Funny more than any other running joke. It hardly takes the entire Slashdot community to moderate a post to +5 Funny, and it doesn't happen any more often than your obligatory Simpsons quote, or CowboyNeal reference, or beowolf cluster, etc.
Experts agree: everything is fine.
It depends on your need for security, of course, but many, even rather small businesses, opt for off-site storage. In a way the idea storage would be at a remote network host...but you would need to worry about THEIR backup policy, also about encryption and access to your private keys.
... so the best available ways aren't being tried.
It's no longer a hard problem, but everyone seems to have decided that they already know the correct solution
OTOH, just imagine what a huge surge of bytes that would put on the internet. Perhaps things are best left as they are.
I think we've pushed this "anyone can grow up to be president" thing too far.
It is absolutely true. It becomes increasingly difficult to create well-formed pits at higher rotation speeds due to the more difficult timing tolerances. Also, it is easier to get predictable burn results at a lower laser power setting.
Uhh....actually, there are no pits being burned in the media. It's rather a phase change in the plastic that either leaves the area translucent or makes it opaque. Stamped CD's do have pits...as they are pressed by a glass master in most cases.
"The strong will do what they want, the weak will do what they must."
-Thucydides
Close, but actually it is inducing a color change in an organic dye. This dye is either green (unburned) or clear (burned), and is sandwiched between a reflective and a non-reflective layer.
-- You are in a maze of little, twisty passages, all different... --
This is the biggest problem with the CD-R market. There's no long-range consistency in the formulation of the discs. Even within the same line, by the same manufacturer, there will be formulation changes, even dye changes. Outside of the brands that make their own discs, it's even worse - you're at the whim of whoever the lowest cost producer was (ie, Sony's discs are outsourced that way.)
:P
I used to buy only TDK. Then I had to switch to Verbatim when TDK started getting cheap on me. Now I'm using Mitsui media. When I started burning CDs on my 2x burner (I now have a pair of 8x burners and a Pioneer DVR-105) I was reasonably confident my data could last up to 10 years (I burned 3 copies, on different brands of CDRs.) Nowadays I haven't a clue as to whether my data will last the year
Time to make a fourth copy of my data and put it on a removable HD...
IsoBuster
AT&ROFLMAO
the point is, it's not a pit/hole, but rather a physical change (chemical, phase, color--whatever) in the medium (an organic dye). So it's not a function of how deep the hole is, as the theory of "slower burning = deeper hole" so requires.
Stupid people make stupid things profitable.
I've talked to companies which make these types of tools and asked the same question. The simple answer is that a normal CDRom is just not built for advanced testing. Testing drives have specific hardware to detect errors that a normal CD can't. Naturally these errors don't influence the percieved quality of the product, since they can't be measured by standard hardware. However it can demonstrate problems with the manufacturing process.
You're joking, right? I hope you are. But if you aren't, then: If something catastrophic were to happen at my friend's house, then obviously I would still have all of my original data at home. Then I would leave a fresh backup at his new place, after helping him get settled in there.
Leaving a CD-R at a friend's house is free. Fireproof safes are not. In addition, what if the burglars were to find and steal that safe, hoping to be able to break it open at their leisure and get the valuables inside? Then you would be wishing you had a current backup off-site.
It actually depends on the drive. I remember back in the day when Adaptec Easy CD Creator put out a regular newsletter and discussed this. The older drives would produce less crc errors at slow speeds. Newer high speed drives will do better at high speeds because that is what they are designed for. The higher speed drives are only calibrated at the top speed burns.
BTW, I had some audio cds stored in my car that lasted over 5 years. I finally threw 'em out because they started skipping on some tracks. I still have some data backup discs from the same time perios and they still work fine. Of course they are stored in a less environmentally extreme storage- in the cabinet above my desk.
Just a Tuna in the Sea of Life
> Since Slashdot certainly has its share of political left, right, and women, it's easy to see that no one thing will EVER unite ALL Slashdot readers.
Sure there is. Our love of bandwidth.
if the answer isn't violence, neither is your silence / freedom of expression doesn't make it alright