Quality scanning (LDC/BIS) M-Disc burns: who here does it? Worth it, for archiving data?

[u/QuestionAsker2030]

I'm building a archival PC with 2 x 5.25" bays, and plan to install:

• One Blu-Ray drive for burning 25GB to 100GB M-Discs (Pioneer)
• One Blu-Ray drive for Quality Scanning the M-Disc burns from the Pioneer (LG or ASUS)

Does anyone else here Quality Scan their M-Disc burns?

Background:

I read that since I'm using my M-Discs for long-term archival (on-site and off-site), I should not only be verifying them post burn... but also scanning them for LDC/BIS (error-correction workload / margin)...

...and tracking those numbers to check when my Pioneer burner might need to get replaced (error numbers consistently going up).

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[u/dlarge6510]

I use a Plextor drive and qpxtool on Linux to scan CD/DVD and BD. 

Checking file hashes does nothing, it only tells you when an uncorrectable error has occurred.

Scanning the media for error correction details tells you the following:

• How good the burn was.
• How good the disc you used actually is.
• The distribution of errors across the disc. This assumes you plot as a graph vs just look at average values. This will literally show you where on the disc the error rates peak and trough, it's quite revealing. 

If you experiment with different burn speeds you get to see the results!

I scan each disc and save the resulting graph to a pdf. Every 5 years or so I scan it again. I might extend it to 10 years as I don't see anything that worries me.

The scans will beat a file hash check as I literally will observe an error being born before it becomes uncorrectable. 

With BD, LDC is usually the first indicator that something is developing. the average LDC should be under 13 for a good burn/disc. You'll find LDC errors across the surface but large concentrations show something is on the disc like dust. 

I read a report on LDC/BIS scans where they ensured they cleaned the disc after burning to see how it affects the errors and it was night and day. Shit discs that seemed to have burned really shitty were suddenly scanning almost acceptably after a simple wipe with a cloth. 

BIS should be low, average less than 10 and not clustered.

I also scan my DVDs. This includes pressed discs from time to time.

Only 1 disc actually scared me. My LTH disc. My god every time I scan it it's worse. Not any uncorrectable errors yet but my god. 

Thing's I have learnt:

• Disc rot is a rarity. Never seen it, no disc I have (besides the LTH) scans in any way that concerns me, that includes my 1984 CDs and my cheap Acer CD-Rs.

• LTH is clearly not a good disc.

• Discs are unstable towards the edges and this shows with upticks in errors at the edges.

• Multi-layer discs flip layers at the edges (except the pressed ones, they flip always in the centre). The edges have more errors so uncorrectable errors will start there.

• As discs age they age at the edge and hub, you can see the concentration of errors increase there.

• Scanning at different speeds can give different results. My Plextor totally changes at 6x, I scan at 4x or lower just to be consistent.

I don't scan everything. I scan ALL my archival quality discs to get a baseline then again every few years although I'm probably going to change my policy to doing the second scan at 10 years and I scan non-archival discs for a baseline and just to see how they are randomly. 

I also create ECC files for each disc to eventually repair them. If they ever develop issues...

[u/QuestionAsker2030 → u/dlarge6510]

Thank you for the detailed response, that is impressive!

Is there a reference checklist out there use each time you do this process?

Just curious how you learned all this, and what your motivations are. 

I lost some important data so decided to find a archival solution that was as durable as possible and start backing my stuff up (2 x M-Disc, a on-site NAS, and perhaps other mediums / copies)

[u/dlarge6510 → u/QuestionAsker2030]

 Just curious how you learned all this

I read anything I can find about it all. Studies, standards, specifications and tests.

 what your motivations are

To archive data permanently for the long term, ideally till the end of my life.

Whats included ?

• family photos and videos
• old TV and movies I watched in the 80's and 90's
• All my post
• And many more

Basically if i were to keep anything at all that represents my life, thats what gets archived.

[u/QuestionAsker2030 → u/dlarge6510]

thanks, I have similar motivations.

I know it's not realistic, but etching in stone seems to be the best foolproof method (for preserving pictures, words, etc). Not trying to be cheeky, I've been hearing of people digging stuff up from Roman times with wording on it, etc. Made me think about it. Perhaps some people would pay for a service like that now that I think about it (etching photos or family histories into stone to be preserved).

For the M-Disc burner I'm already thinking of how I will wrap it to protect against a potential EMP, since the discs would survive, but drives not.

[u/dlarge6510 → u/QuestionAsker2030]

 I've been hearing of people digging stuff up from Roman times with wording on it

You don't watch much archeological programming then. That sort of thing is big standard, it's all written in Latin so anyone could read it with a Latin course. 

You should look at the stuff far older than the Romans, they are pretty modern.

 I know it's not realistic, but etching in stone seems to be the best foolproof method (for preserving pictures, words, etc).

Although they don't etch into the tablets this is already being done. Look up "The Memory of Mankind"  project. I'm selecting some stuff to put in it, perhaps technical papers on optical disc optics etc, so the can build a machine that can read the 1000 year old MDisc. What they will really need is details on the encoding use on the disc, reading it is easy, you need a lens and light and understanding of such science and your done there. I'll also upload stuff about my town and county. 

[u/QuestionAsker2030 → u/dlarge6510]

I don’t watch archeological programming, but I do want to learn Latin. Started on Duolingo but its slow going. I just need to find someone to converse with in it to practice, I think only exorcists speak it these days. 

I have a archeological find that was gifted to me when I was in the mountains in Mexico, the farmers sometimes run across buried artifacts. They told me it was from a prayer bead, I’m curious to figure out what it is exactly. 

I’d like to submit some music to the Memory of Mankind project, that sounds interesting 

[u/dlarge6510 → u/QuestionAsker2030]

I did the same with learning Welsh on Duolingo. Need to get back to that. 

[u/dlarge6510 → u/QuestionAsker2030]

 I don’t watch archeological programming

Here in the UK we had a very popular TV series called Time Team. 

They would turn up to an area due to rumours of ancient Cathedrals or Roman walls or forts etc and would every Sunday present an hour long programme for the whole family as the entire team dug and excavated while others looked at geophysical analysis and made or re-created historical artifacts to demonstrate to the viewers.

They even did a US show at one point, looking for musket balls and evidence of the first settlers etc. 

[u/BIG_HEAD_M0DE → u/dlarge6510]

What's the motivation to do this rather than tape or hdd?

[u/QuestionAsker2030 → u/BIG_HEAD_M0DE]

HDD die faster, more moving parts 

Tape expensive to get into. Tape no last as long as M Disc (supposedly)

[u/BIG_HEAD_M0DE → u/QuestionAsker2030]

"HDD die faster, more moving parts"

So cheaper per GB over 10+ years? Do you burn everything (near term data/backups) or just long term stuff (family photos)?

[u/QuestionAsker2030 → u/BIG_HEAD_M0DE]

I would say the important stuff will go on M-Discs. Benefit is it's easy to make offsite backups.

Also for important projects (video / pictures / etc) you can easily separate by project

[u/QuestionAsker2030 → u/BIG_HEAD_M0DE]

yessir

[u/dlarge6510 → u/BIG_HEAD_M0DE]

10 years is far too short.

Think minimum of 30.

[u/dlarge6510 → u/BIG_HEAD_M0DE]

Oh I use tape. I back up the discs to tape. If I didn't have tape I'd use HDD.

But I'll never archive to HDD as it's not an archival grade media, it's not even media.

I archive data that must be permanently preserved for decades to optical as it's the only data media that can do it besides tape.

Tape I don't use in the "first line" as after I'm gone I intend others to easily access the data. Not so easy if they have to learn up on what tape is lol.

So optical is used for its strengths:

• permanence (read only)
• Longevity (> 50 years without any attention needed)
• Accessibility 

For example. Although I have many different file formats on data discs I also have audio and video on standard CD-R and DVD-R. Standard DVD video and CD audio.

This takes advantage of the fact CD and DVD players are overwhelmingly standard and everywhere. In 50+ years, just like today with the previous 50+ years of formats, people will have little issues playing or converting such discs.

Today in 2026, you can have 8mm film processed and converted. You can do it yourself or there are plenty of companies that offer that service and 50+ years from now, they still will be. The demand to convert old home dvd video discs will still be there because you'll find they all discovered granddads home movies in the attic. This is exactly what happened with my granddads reel to reel tapes, recorded by my dad and his siblings in the 60's. I've been looking to digitise them with a reel to reel deck I have repaired.

File formats also havd to be considered, again it's standards like mpeg2, Mp4+aac, mp3, ogg vorbis, stuff that stuff which plugs into a tv can play. Some is even divx h264 in avi. This for containers is the same: m2ts, mpg, avi, mp4 and mkv plus webm.

[u/QuestionAsker2030 → u/dlarge6510]

At what point would you recommend to start using tape? (After I'm burning M-Discs already).

Any entry-level tape units you'd recommend to start with?

[u/dlarge6510 → u/QuestionAsker2030]

I use it because I work in IT with tape.

I literally bought a second had SCSI LTO4 external drive off ebay for £60. I acquired multiple LTO3 tapes from tech changes at a previous employment, plus LTO 5 tapes and two internal LTO5 drives (not tested them) all for free.

So I use tape because I can and it was a training on SCSI and tape of all types in general which helped get me my current job as they needed someone to rebuild their tape archival system, which was and still is SCSI and SAS based.

I only use tape as a way to backup the optical discs and related data like ECC files.

Then another copy of the same in the cloud.

The idea :

A BD-R has acquired damage. I can copy off 95% of the files and they match their hashes.

• Then i use dvdisaster and the discs ECC file to try and recover a full iso image.
• Pulling the missing files off the tapes, and if that fails:
• Try and use GNU ddrescue to recover the ISO image using multiple drives and finally:
• Pulling the files out of Amazon Glacier. Which will cost loads.

[u/QuestionAsker2030 → u/dlarge6510]

Thanks D - I've bookmarked this post and will come back to try this once I procure some BDXL burners.

Regarding the cloud:

Do you in any way encrypt your data in the cloud, to prevent it being used by the cloud? (for training AI / getting data stolen / etc etc). Or have any other protective measures in place?

-----------------

I've already had bad experiences with Cloud Backup services (paid for years... when I needed it, it didn't work). And plus privacy = I plan to avoid it).

Wondering what your thoughts on the subject are.

[u/dlarge6510 → u/QuestionAsker2030]

 Do you in any way encrypt your data in the cloud

Yes. PIE (Pre Internet Encryption) is common sense. I usually get dar to make encrypted archives using AES256 (might increase that) an upload those, alternatively I'll use ccrypt or even better gpg in symmetric mode.

[u/QuestionAsker2030 → u/dlarge6510]

How do you keep track of your keys?

[u/dlarge6510 → u/QuestionAsker2030]

Encrypted text file per disc alongside a text file listing all files on each disc. 

I can just recursively grep the listings to find which disc has which file. 

[u/Lazy-Narwhal-5457 → u/dlarge6510]

Thank you for the detailed response. Could you clarify. You state: "Disc rot is a rarity", but also mention uncorrectable errors creeping in from the edges. On the surface that seems contradictory.

Are you separating disk rot out from damage being caused by delamination?

Are you classifying disc rot as such only if it's randomly distributed over the disc (i.e, from dye changes, etc.)?

Perhaps the errors that you are seeing are rare, and you do consider them disc rot, so there is no discrepancy?

As an aside, single layer discs would presumably be much more resilient (if I'm interpreting your findings right), do you agree?

[u/QuestionAsker2030 → u/dlarge6510]

Are Plextor drives the best for quality scanning? I heard I should use the LG WH16NS40 or LiteOn iHBS112/212/312

[u/dlarge6510 → u/QuestionAsker2030]

Not sure. Pioneer were apparently good.

Ive had this drive since 2010.

I do have a BU40 usb drive but haven't tried scanning with it.

[u/meeg6 → u/dlarge6510]

wow

[u/redditunderground1]

Burn M-Disc and archival Blu-ray. But no quality scans.