The burn that silently failed

vbimport

#1

Long-ish post, skip to part 2 if you don’t care for a backstory. This is kind of a rough draft, excuse me for that. I tried to be as clear as possible. TL;DR clarification at very bottom.

1. What happens when you trust DVDs too much.
My data is important to me. So like any other reasonable person, I regularly backup my data off of my harddrive to ensure that I don’t lose it. I don’t put my files and information on other harddrives, but on numbered DVDs which I store in a secure place.

This has always made me feel safe, because I have always thought that DVDs weren’t prone to the same failures as Harddrives. I thought that once I got my files on a DVD and took care of it, I wouldn’t have to worry about losing them. Recently I found out I was wrong.

A few days ago, I burned some really rare files onto a DVD using Nero. Nothing unusual, I’ve done this many times before, I just made sure I was extra delicate with those DVDs. Nero finished burning without a problem, I tested a few files on the disk by opening them, and everything was OK.

Yesterday I pop the disk back in again, looking to copy one of the files off of the same disk and it doesn’t work. The computer actually freezes trying to copy or open this file, and I have to resort to ejecting the disk. After ejecting the disk, I get a dreadful message telling me that there was a read error. I’m shocked. I try opening and copying other files on the same disk, in the same subfolder and they work fine. So I figure that some files work, and some files don’t.

Normally, I’d just burn another DVD and test all the files this time to be safe. Only one problem: all the files on this DVD are no longer on my harddrive. Also, they came from numerous sources, some of which no longer exist. Damn.

Now I’m stumped as to what I should do, and I’m quite angry that this happened so easily without warning. When I think about it, I worry that there may be other disks with faulty files that I’m not even aware of yet. Some of these may be recoverable, others may be gone forever. :frowning: Today I appreciate all the times I’ve had burns that failed at 80% and up due to a write error, even though that would piss me off.

2. Ways to guard against burns that silently fail.

Preventing this from ever happening again is a top priority of mine. But how?

There are two factors that come into this for me: Reliability and Time. How much can I trust any solution to tell me that the files on the DVD will work? Also, regardless of whether this is done before or after burning: how long will it take?

If a solution is really, really reliable but takes 30 minutes to an hour per DVD, that’s a bad solution. If it’s fast as hell, but has a high chance of lying to me, that’s also a bad solution. I care about my data being accessible after I burn it, but I don’t have that much time to waste as well. I’m a (soon to be) college student with only one computer, one DVD burner and a ton of files on a small harddrive.

Here are ideas that I have been thinking about, and I will share them with you, however primitive they may be. If you know of something better, or have something to recommend, please share it. That’s what I made this thread for.

  1. Make a text file with the CRC’s of each file before it gets burned. After the DVD is burned, compare all the CRC’s on the DVD with those in the text file. If they all check out, disk is good. If a few fail, the disk is bad, re-burn.

    1a. Assuming that a file on a DVD will have a different CRC when it can be copied/read, and when it cannot be copied/read. If this isn’t the case, then this method is worthless.

  2. A small script would be ran, and it would try to successfully “open” then “close” each file on the DVD one by one. All it would do is see if a file can be opened. The script wouldn’t actually open an mp3 or movie and play through it, or try to run an .exe.

    2a. In my mind, what makes this different from the first method is that you aren’t doing any deep or intensive scanning, just a quick open() and close(). Quicker than CRC’s right?

  3. Just find a better way to burn. It’s possible that the previous two methods are unnecessary, and all I need to do is enable a magical option that makes sure no faulty data gets to the disk. Maybe, but there’s already some basic error-checking going on during burning (or else why would Write Errors exist?) and I don’t know how I feel about putting my faith in ‘better error-checking’ even if it did exist. I feel that the burner has failed me, and I can’t really trust it. I’m still open to this if you can convince me I’m wrong in doubting it.

TL;DR -
Burned a DVD with Nero, that ‘successfully completed’ with no errors. A few days later I am unable to copy/read/open files from this ‘successfully completed’ DVD. Now I’m looking for an automatic solution that will test files during or after burning and tell me if those files can or cannot be copied/read/opened.

Please don’t ask “Why can’t you open all the files yourself? hurrrrrrrr” I’d like to see you do that with thousands of files, one by one.


#2

Please tell us the media code of the DVD & the manufacturer that the disc is labelled with.
If you respond with Ritekxxx … we will point our fingers and laugh at you.

To get your stuff back …

  1. Use blindsuite to dump the DVD to your HD, at very low speed :wink:

  2. Mount the image created using daemon tools & copy the files off the virtual DVDrom :wink:

  3. Use decent quality media like TY or Verbatim :wink: that has a better quality control & is more consistent between batches than other manufacturers.

  4. Use imgburn to burn, rather than Nero. Nero reports 100% fine, even with fubar discs :stuck_out_tongue:

  5. Use CDCheck (postcardware/freeware) to do a comparison of your disk, with the folder you’ve backed up.


#3

If you want optical media that checks for errors as you burn, go to dvd ram. Be prepared to pay a large amount for each disk and expect slower burn speeds. Doesn’t sound like that is an option for you, so the next best thing is to make multiple backups on known good media like Verbatim or Taiyo Yuden—plus storage on extra hard drives.

All of this is expensive, but other forms of long term data storage are also expensive, ie tape.

And you might want to try ISOBuster to recover your lost files.


#4

Thanks for the speedy and highly useful posts guys.

debro, surprisingly my disk turned out to be a good one. CMC MAG.E01 [Staples]

http://www.videohelp.com/dvdmedia.php?dvdmediasearch=&dvdmediadvdridsearch=CMC+MAG.E01&idexact=1&type=11&size=All&dvdburnspeed=All&order=Mediacode&hits=50&search=Search+or+List+Media

Videohelp tells me that it’s good all around, and I believe that because most of my burned DVDs are Staples. I remember having bad luck with my Memorex DVD bundle, which I planned on saving until I was done with the staples DVDs. I’d be surprised if this was a drive problem.

Thanks for the ImgBurn suggestion. I guess commercial software isn’t always the best, heh?

Kerry56, I plan on moving up to tape in the future.

I’ll try the recovery methods posted, but I’m not too optimistic about it. If something can go wrong, it usually does when it comes to computers.


#5

Have you tried the disc in a liteon drive? They tend to be better readers than most.
I’ve had issues with CMC manufactured media. The discs were actually fine (Benched & scanned fine on the liteys), but non-liteon discs had (unknown) issues reading them.


#6

No, I haven’t. I’m considering getting a LiteOn drive now.

Once again, thanks.


#7

Despite your Username, surely you know a nerd that owns one of these drives? :slight_smile:
Oh well, I suppose you can pick up Litey DVDwriters now for less than $50au / $30US.


#8

CDSpeed has a feature called [I]transfer rate test[/I].

When set to “accuracy” (that’s important), this test tries to read all of the user data at maximum speed.

Slowdowns during the test indicate that there’s a problematic area in terms of burning quality or media mechanical characteristics (or heavy CPU/IDE load, but to avoid this the test can be run in real-time priority mode). If any bit of data can’t be read, the test fails with a CRC error.

If the test is perfect, you can be certain that all of the user data can be retrieved in good conditions, in the very testing drive at least.

That’s the best real-world test to use IMO. With a 16X reading drive, it takes about 5 minutes. :slight_smile:


#9

E01 are variable in quality from brand to brand, and also they burn very poorly in some older drives (like Pioneer 107/108), which gave CMC a bad reputation that was not really deserved.

The only really consistent E01s that I know are the HP branded.

Anyway, a defective disc can happen even with premium brands like Verbatim. So it’s always better to check the actual readability of the disc after the burn. :wink:


#10

A last recommendation: for really important/rare files, burn two copies on two different types of discs. Optical media is prone to degradation, some discs/models being less stable than others. Better safe than sorry. :frowning:

E01s are on the stable side, though.


#11

If you have data that is that important, you might want to learn how to do some error testing too (error scans, transfer rate scans etc). I have had very good luck with e01 including several staples brand disks and have disks that are years old and read fine, but I have had at least 1 burner that didn’t burn them well, and another that didn’t burn them well with certain firmwares (sorry, cannot remember which drives as I tend to burn most e01 on my 3500 since it burns them the best). There is no media that will burn good on every drive/firmware combination out there so it might be worth checking to see how your drive likes it. Beyond that, as has been said, even with the best media, there is going to be a few defective disks out there. That is the nature of mass production. Double backups are therefor a good idea (on different media as mentioned so if one pack is bad, the other should be good).