Warning: Don’t Stack Blank BD-R DL Discs in Sleeves!

vbimport

#1

After having made a relatively expensive mistake, that rendered some (seemingly) perfectly good BD-R DL’s into an unwriteable mess, I shall proceed to warn everyone not to stack many BD-R DL discs in sleeves, especially with heavy spindles on top!

Full story: http://goughlui.com/2014/12/24/warning-dont-stack-blank-bd-r-dl-discs-in-sleeves/


Aging and older BD-R/RE media scans
#2

Thanks. Sorry you had the problems, but it is good that you wanted us about them.


#3

The sleeves were known to make things go bad after the discs had already been written; good to have confirmation that it can affect things before burning them, too.

The folks who have had issues with storage of previously written discs have been able to revive them with a heat gun to undo the pattern left by the sleeves. I’m not sure if the same revival technique could have helped, or if there was more damage done than just that.


#4

I’ve also noticed this myself back in the DVD days.

You don’t need to have anything pressed on top either. Sometimes just the pressure of having two discs back to back in a cd/dvd wallet with the whole wallet filled with discs can cause it.

Some wallets are tighter than others too. I’m currently using a sleeve system but the discs are stored upright with no pressure from other discs so we’ll see if that causes any indentation.

BD-R discs “hard coat” probably gets more messed up than cd/dvd too. It’s probably just a lacquer or something cheap. Would have been nice if the plastic itself was scratch proof.


#5

I wonder if BD-R/RW are using a softer polycarbonate than DVDs (presumably for its moulding or optical properties). Even the best DVD±R/RW seemed to use a slightly softer plastic than the better CD-R. Maybe as the track pitch is reduced the harder plastics cannot mould to the finer detail?

If that is the case, hard coating would not offer any meaningful protection from the pressure applied by tight-fitting/stacked sleeve cases. And it might explain why even the cheapest BD-R discs have a hard coating.

Just a thought.


#6

For what it’s worth, there is a quick reference page with the Do’s and Do Not’s of storing CD/DVDs available @ http://www.itl.nist.gov/iad/894.05/docs/CDandDVDCareandHandlingGuide.pdf

For most part I’d say this also applies to the BD as well. Some good bed time reading…


#7

Well, sadly, I have an update to this one. Turns out my 6-year old TDK burns in other types of sleeves stored in a mixture of vertical and horizontal orientation [B]all have issues with readback[/B].

However, I did follow the advice of @Albert, and it seems that the heat gun trick does work to some degree - it doesn’t restore the disc to perfect health, but it does make a big difference in read-error rate in scans and recovered all of the six discs I had issues with in the first attempt. I count myself somewhat lucky.

More details, see:


#8

Thanks lui_gough for writing about this in detail. Have you (or anyone else) seen the same issues with original Panasonic media (non-OEM)?

I’ve had the exact same experience recently with written BD-R media stored in the same sleeves (maybe it’s the stuff we get in our local market that’s the issue?). What I’ve now resorted to doing is storing everything in spindles and file them away in a dark storage box (no sunlight coming through). This works out OK for me as it’s coincidentally the most space efficient method and I don’t browse through the collection often. Jewel cases are another way to go if you’ve got the real estate.

Also after reading into the longeivity of BD-R DL disks, I am now thinking twice about purchasing them.

PS: I am still hesitant to use HDDs instead of optical media for the reasons: 1) not read-only 2) drive mechanics fail in an absolute manner. This is despite ability to keep multiple copies of HDDs which complicates data management.


#9

I do have only a handful of BD-R DL 2x MEI’s under Sony branding burnt 6 years ago - they seem to be okay but they do have some sleeve patterning on them now. Readability seems okay but not perfect, but I can’t really bother to scan.

I find the sensitivity of the data layer to the patterning on the sleeves to be quite irritating. There’s a chance that stacking them on top of other discs with printable coatings could also cause issues because there’s some roughness to them and I’ve had some cases where some flecks of printable coating start to stick to the disc above necessitating cleaning.

Of course, spindles are a nice way to keep them if you don’t go through them often and won’t have the patterning issue with the sleeves. However, because I did get some discs “randomly” sent to me in sleeves from eBay sellers in Japan, I didn’t keep enough spindles for all of them. Too late for most of my collection of over 350 discs though …

That being said, optical media has lost my favour because of speed and cost. Assuming your time is worth nothing, and the drive is worth nothing either, most BD-R SL discs don’t sell cheaper than about AU$0.80/disc in bulk.

On a $/GB basis, assuming you fill every disc fully, this works out to be [B]3.2c/Gb[/B].
A WD Green 3Tb drive goes for 4.3c/Gb, which is about 34% more expensive, but hardly breaking the bank. If your discs are averagely filled to 18.6GB, then your effective media cost is the same. BD-R DL is even more expensive.

However, when you factor in the time, burning 3Tb of BD-R SL discs (120 discs) at 8x (12 minutes a disc) will cost you exactly 24 hours. Doing a 3Tb drive fill only takes about 7 hours. The cost difference in media alone is $33 for 17 hours of extra hassle (under $2/hour).

That’s before you factor in the discs volumetrically take up more space, and creating a second copy will cost you a similar amount of time.

Of course, the idealism that discs can be read by any drive, and has “read only” safety is practically undeniable, but I’ve had enough issues with data loss on BD-R - some permanent thanks to Ritek, that I cannot justify further investment in it. At least a hard disk is rewritable, and you can produce parity files to cover for “bad” sectors if the drive hasn’t completely failed.

My experience with hard drives is generally more favourable. I’ve carried home ex-business Maxtor hard drives of 120Mb from 1991 that still work just fine today. Not to say that they all do, but I haven’t suffered major data loss with hard drives in general.

You can flag partitions to mount read-only (subject to the OS’ compliance) - e.g. for NTFS this involves some diskpart commands.

  • Gough

#10

Wow I feel like a celebrity getting mentioned on your site Lui :stuck_out_tongue:

I am almost thinking along the same lines as you with abandoning BD-R for storage. If I get some failures, I will most likely spit the biscuit much faster than you have! Only thing that gets me scared of HDD is that you lose much more data and it’s all unrecoverable sometimes. Having several HDD failures too has probably led me more to optical storage.

I’m hoping SSDs will become cheaper soon, there’s no reason for them not to apart from pure price gouging…


#11

I feel the same way about SD cards, price gouging. A decade ago I thought I’d go from optical media onto SD cards when they price/capacity improves, however it has not happened. Neat thing about SD cards is that they have convenient read-only switch. I hope some day HDDs intended for archiving get this feature too, at least within the underlying storage protocol where end-user can control it from BIOS/UEFI layer.


#12

Sad thing about flash memory is that [B]NONE[/B] of it is really tuned for archival. Generally they claim endurance of close to 10 years, but since it’s based on trapping charge, the endurance actually changes as the cells are worn as they get “leakier” over uses. It’s actually quite technical, but we have had certain motherboards and prototyping boards with flash-memory based BIOS/bootloaders fail as the chips eventually lose their charges and lose their written data. As long as it is rewritten before the ECC fails to correct it, then the data will survive, so there is some reason to “refresh” the surfaces.

However, that being said, I’ve been lucky with HDDs - part of it is treating them well, having a good ear for strange noises, reading the whole surface periodically to check for health (i.e. scrubbing) and watching the SMART data.

There is no one “perfect” solution for everyone, but I feel a bit miffed that my investment into Blu-ray has turned to mush so quickly (relatively speaking) compared to the earlier generations of optical media.

And @cd pirate - you’re welcome :).


#13

Oh and I forgot to mention - SD cards do not actually have hardware write protection. The switch is just an annoying piece of loose plastic which pushes on a switch inside the socket - if the switch in the reader goes defective, all cards may be stuck in read only or read-write mode. I used to have enough had contacts on the sockets on cheaper card readers that I’d just solder them closed to make sure all cards could be read/write/formatted.

It’s definitely NOT real protection. I suppose for hard drives, you could always use a pricey (hardware) write blocker as used in forensic investigations if read-only-ness is a requirement. Maybe archiving it with checksums, or using an archival format with CRC checks can provide additional certainty that the data has not been vulnerable to bit rot.

The main issue is that the volume of data we can handle continues to grow - optical discs seem to have stagnated and pushed the boundaries of what is physically possible right up to the point of questionable reliability. Many of the advantages which optical media had at the beginning have since evaporated - when CD-R’s came out, many hard drives were of the same size as the discs.


#14

[QUOTE=sengork;2751415]For what it’s worth, there is a quick reference page with the Do’s and Do Not’s of storing CD/DVDs available @ http://www.itl.nist.gov/iad/894.05/docs/CDandDVDCareandHandlingGuide.pdf

For most part I’d say this also applies to the BD as well. Some good bed time reading…[/QUOTE]

It seems that BD-Rs have a surface coating that is elastic and can ‘flow’ or deform by tiny amounts over a long period of time.

Since they mostly come from the factory horizontally (on spindles), since most people stored them prior to burn horizontally (on spindles) and since they are mostly burned horizontally, it is my theory that they should be stored horizontally also. Not vertically as per the NIST recommendations.

Storing them vertically will cause the surface to deform over time due to gravity and affect readability. Although if they are elastic they should eventually return to their initial state if put back horizontally (some people have tried to speed this process up with hair-dryer but I believe they should just be left alone).

It’s just a hunch and it might be complete nonsense but it should be quite easy to test with some control discs.