
When Discs Die - imartin2k
http://tedium.co/2017/02/02/disc-rot-phenomenon/
======
jabl
Back when hard disks were expensive and CD-R(W) discs (relatively) cheap, I
used to do backups and move less used stuff to CD's. A number of years later
when this was no longer true (and CD's were becoming laughably small) I moved
all the data back to hard drives. In the process I discovered that a fairly
large fraction of the discs had developed some minor corruption. Luckily I was
able to recover the vast majority thanks to GNU ddrescue (
[https://www.gnu.org/software/ddrescue/](https://www.gnu.org/software/ddrescue/)
).

The bottom line is that for long term preservation you really need to keep
multiple copies, preferably on multiple mediums, and regularly check and
recopy them before the medium gets so obsolete you can no longer access it.

(Yes, I realize the article touches factory pressed discs rather than CD-R's
although there is a short mention of such discs too)

~~~
blackflame7000
I wonder if there is some sort of archiving software that is able to encode
parity bits similar to how RAID5 works in order to help recovery in the event
of corruption to part of the disk.

~~~
DanBC
You can use WinRAR with zero compression and recovery volumes.

This is useful if you have a bunch of little files - you WinRAR them into a
single file with recovery volumes, and then you can create a bunch of PAR2
files on top.

I'm not saying this is a sensible thing to do.

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stinos
This knowledge should be more widespread imo, pretty sure there are still
people out there assuming CDs are like indestructible. Once I started a job
and after a couple of months I discovered there was a closet containing
hundreds of CD-Rs all neatly labelled and seemingly containing things like
fMRI data used in research. You should have seen the faces of colleagues and
the guy responsible for the backups of their data when I told them CD-Rs where
not exactly the most durable way of storing important data. (I figured this
out because of the very first audio cd copies I had started to develop
unexplained errors). They didn't believe me so I randomly picked a couple of
discs and like the third one was completely unreadable (I/O errors on ls or
so, don't remember).

~~~
mrmondo
Gosh I remember how many IO errors occurred on those early and / or cheap CD-
Rs like 'Transonic', 'TDK', 'Maxell' and all those other dreadful light green
or light blue coloured Cyanine ink based coasters. I remember trying to backup
my MP3 collection many, many years ago and trying to afford tens upon tens of
decent quality Verbatim or similar brand discs and burning them slower than
their top rated write speeds in an effort to make them as durable as possible.

I remember getting my first 40x or 50x writer, that thing sounded like it was
going to blow apart at any moment, I think I used to limit write speeds to a
maximum of 16-24x at most.

And then hard disks (or hard discs which I believe is an equality technically
valid spelling) started to drop in price, ended up with a pile of those
quantum fireball 850's, if you had these you'll remember having to 'tap' them
on the top to help them spin up as I assume the baring fluid / grease would
harden enough to prevent the drives from spinning up if they'd been powered
down for more than a week or so.

------
jim-jim-jim
There are works out there where the master tapes have long since vanished that
we can only enjoy today by virtue of the durability of the vinyl/shellac the
original copies were pressed upon. It's scary to consider how more obscure
digitally-issued releases risk evaporating entirely.

I dismissed analog purists like Steve Albini as cranky old men until recently,
when I realized they have a real point w/r/t preservation.

~~~
Nav_Panel
The major film studios already do this: they create a tape print (this process
is one of the only reasons Kodak still exists) of every film, including
digitally shot/processed ones, and store them underground. A hard drive might
die in 5 to 10 years but film is guaranteed for 100.

------
chiph
I bought my first CDs in 1984, and played them on the world's first CD player
- the Sony CDP-101. Of the hundreds of discs in my collection, I had maybe 3-4
from that decade go bad. What worked for me was storing them in the jewel
boxes on edge (not laying flat), indoors away from sunlight.

So far as "Disc Rot", as a former LaserDisc owner, I'm very familiar with it.
On the 12" platters the glue between sides could fail and sometimes lift the
aluminum recording surface off the plastic. Or the edge seal would fail and
oxygen would turn the aluminum into aluminum oxide. Both would make a $70
movie (in 1988 dollars!) unplayable.

I'm sad to see CDs go. As has been told, they're the first recording format
that was replaced by one with inferior sound. I never had many LPs, and don't
have the storage space for them, but I get that they get the listener more
involved - you have to consider which album to listen to and set aside 50
minutes (including the side flip). You can't just hit "random play" and walk
away. So it's nice to see them make a comeback.

~~~
rangibaby
CDs had a big problem with mastering. They either have a bad sound from CD
being a new format (Zappa 80s CDs suffered from this) or since the mid-late
90s are brickwalled to hell thanks to the loudness war.

Obviously there are plenty of fine CD versions of albums out there, but I
heard enough poorly mastered CDs and spent enough time searching 2nd hand
stores for known good versions to not be worried about the format going away.

~~~
chiph
> CDs had a big problem with mastering.

You are correct. Lots of the early releases once the goldrush started still
had their RIAA equalization on them (aka "shovelware"). Even those that used
original sources simply didn't sound all that good because of the mastering
engineer's inexperience (first release of _The Wall_ , I'm looking at you).
There were still gems made though, like _Brothers in Arms_

Because of the loudness war, I've started looking for earlier releases on
discogs.com. Anything listed as "Remastered" is viewed with suspicion.

[https://en.wikipedia.org/wiki/Loudness_war](https://en.wikipedia.org/wiki/Loudness_war)

------
foxfired
Few years ago I bought a new DVD drive and it came with a CD that claim to
last for a 1000 years. [1]

I really wish I could test it, but I lost the disc already.

[1]:[https://en.wikipedia.org/wiki/M-DISC](https://en.wikipedia.org/wiki/M-DISC)

~~~
Stratoscope
If there were a CD that guaranteed I would be able to use it in 1000 years, I
would buy it in a minute!

~~~
bitJericho
This is the company that makes em.
[http://www.mdisc.com/](http://www.mdisc.com/)

~~~
sokoloff
I think Stratoscope's point was the guarantee that _Stratoscope_ could still
use it in 1000 years (IOW, that they'd still be alive then).

~~~
bitJericho
They've been around for 5 years and good quality brands support them. Maybe
they won't last, but it's a better gamble than a pack of cd-r discs from
walmart!

~~~
sokoloff
Let me be a little more explicit. Stratoscope was willing to purchase the disc
on the promise that Stratoscope would _personally_ be able to read the disc
1000 years from now.

IOW, not just that the _data_ would be there and readable, but that
_Stratoscope (the person)_ would also have lived another 1000 years.

~~~
bitJericho
Ahaha that blew right over my head!

------
vionix
This is my nightmare, I spent years collecting for a full PAL Sega Saturn
collection. Reading 'disc rot' in any form always reminds me I need to
prioritize ripping my collection sooner rather than later.

------
smaili
_But when I learned about this problem, I checked my several hundred discs
between Sega CD, Turbo CD, Saturn, and even Dreamcast games and found DOZENS
had this problem. Several expensive games I owned were mint—except when held
to the light I could see one or more little white dots that proved my game had
damage. Some of these I went back to play after not touching for years and
found they now would occasionally lock up or not play at all. I had a few
FACTORY SEALED games that I opened and found the same thing.

It has been a nerve-shattering nightmare for a collector like me._

So should I worry about my factory sealed copies of FF7 and Xenogears? Also,
is there any sort of "rot" that may occur with cartridge-based items? I have
some unopened NES and SNES games as well.

------
simooooo
Never thought about it, but if you're a collector of some sort you would be
pissed to see your collection destroy itself through no fault of your own

------
laktak
If you backup your data (on whatever media) I'd recommend to use some kind of
bitrot detection tool. For example
[https://github.com/laktak/chkbit](https://github.com/laktak/chkbit)

When you later restore you will at least know if/what is damaged. Multiple
backups help too.

------
ams6110
Never liked the CD/DVD physical medium.

Convenient, yes. Sounds great too. But far more prone to physical damage
(scratches, etc) than tapes or records, in my personal experience. Lost count
of the number of times a $20+ movie was destroyed after being in a childs
hands.

~~~
smonff
Mini Disc or cassette seemed better because there were a case around the
support that was making harder to damage it. If for some reason, a cassette
was broken, it was still possible to move the tape to another case (tricky but
not impossible, nice little hacks needed).

People got too fascinated by the shinny colorful reflection of CDs.

~~~
stinos
_fascinated by the shinny colorful reflection of CDs_

And then later on even more fascinated with the production of all black cd's
etc. To be honest, I like those as well, probably just beacuse it's something
different.

And yes there's something to say for the sturdyness of MD and the 'openness'
(almost open-source like lol) of tape.

------
mrmondo
On the subject of discs, I just realised I can't actually remember the last
time I used CD / rotational optical media of some kind, I honestly can't! If I
had to guess what the reason for it might have been I'd probably go with some
obscure band (music) that only had physical distribution - but generally in
those cases (no pun intended) I'd most likely but the CD to support the artist
then check on what.cd (R.I.P) (pun slightly intended) and saved myself the
pain of finding an optical drive and ripping it into my collection. It's
likely it would have been something like that I think.

Sorry for being a bit off-topic there but it was a bit of a 'oh, wow!' moment.

------
CaliforniaKarl
Thinking on the 3-2-1 backup strategy[1], the "2" refers to "two different
mediums". Some say that means two different hard drives, but with articles
like this I argue that it should be "two different forms of media."

Of course, that's just referring to my personal data. With media like what is
covered in the article, copyright law (incl. the DMCA) comes in to play,
potentially limiting your options.

[1]: [https://www.carbonite.com/en/cloud-
backup/business/resources...](https://www.carbonite.com/en/cloud-
backup/business/resources/carbonite-blog/what-is-3-2-1-backup/)

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AstralStorm
A related question is when flash memory dies.

~~~
d33
Replaced by what?

~~~
adrianN
Memristors?

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NTripleOne
Man... this post makes me want to go rip all my old disc-based PC games,
but... I don't even have an optical drive in my PC anymore...

~~~
khedoros1
That's easy to fix. External drives are pretty cheap (~$25 for DVD). Or you
can track down ISOs, even for fairly obscure things, various places online.

------
BrailleHunting
Cheap bootleg DVDs from China often experienced rapid rot because of poor
quality control.

