Mastodawn

Dan Piponi Feb 6

@djlink Yeah, I've finally got around to the process of making iso clones of all of my old DVDs so I can throw them out and I'm doing a 2-tier approach with SSD for convenience and cheap stable HDD for long term.

Also worth noting that HDDs are better at detecting problems before it's too late.

David Amador Feb 6

@dpiponi it's possible my PS4 slow HDD might outlive the PS5 fast SSD xD

lucasmz (en)Feb 8

@dpiponi @djlink i learned recrntly that they're apparently 2.5 and not 3.5 HDDs which makes them as slow as they were. 3.5 HDDs are fine honestly and I don't see much need to go faster than they usually do on games

Bruno Philipe Feb 7

@dpiponi @djlink if the DVDs are pressed (not burned), I'd expect them to outlast both SSDs or HDDs. (Save for manufacturing defects causing early decay of the reflective medium.)

Dan Piponi Feb 7

@brunoph @djlink Yeah, I had a pretty high success rate reading my collection of maybe 200 DVDs, 1-25 years old. But I don't want them taking up space any more.

@dpiponi @brunoph @djlink

Dave Wilburn

Feb 7

There's also something to be said for the convenience of scrolling through your collection of movies in something like Jellyfin rather than flipping through several DVD folders.

And at least in theory you can backup that hard drive.

ROTOPE~1 ⭐️Feb 6

@djlink don't ask about post-N64 Nintendo cartridges.

@rotopenguin 😱

@rotopenguin
(So... Switch and Switch II.)
@djlink

Ozzelot

Feb 7

@rotopenguin
Also definitely do not ask about old phones that weren't on for years, especially manufactured during a certain period, the flash chips from which die like flies. See also Wii U and the 4GB Xbox 360.
@djlink

Khalid ⚡Feb 6

@djlink Short State Drive :P

DigitalStefan Feb 6

@djlink on topic: I’ve today plugged in a Compact Flash card that hasn’t been powered in more than 3 years.

Perfect data retention.

Took a quick dd image of it, just in case.

@digitalstefan @djlink
The highest capacity CF car I have is 1G Byte. It's about x3 the area of the 512G Byte SSD. So the cells could be over 2000x bigger. Likely to be more stable.

I have a 1T micro SD Card in an ex-Chromebook running Linux Mint (64K Flash drive). I don't expect much life from it even powered mostly daily, but the contents are on my server, 2x workstations and a "real" laptop. The 2x workstations and laptop each have SSD and an HDD for user data.

DigitalStefan Feb 6

@raymaccarthy @djlink It's a wonder that we have such sophisticated storage options, but finding out that data retention is poor for SSD's is a bit unnerving.

I have a good backup strategy at home, but I would be annoyed if I lost data to this kind of problem.

My "proper" storage journey started with an 80MB 2.5" HD in an Amiga an has culminated in a 2TB and 4TB SSD in my PC, 2TB in my Framework laptop, 2TB MacBook and 2TB SSD + 2TB microSD in a Steamdeck.

Bonkers, if you think about it.

sodiboo

Feb 6

@djlink it's great that your alt text has a transcription of the screenshotted text (thank you!), but the link at the end ought to be in your post body, not the image alt text. it's easy to miss because you don't mention the link and not everyone opens the alt text, but on some frontends it is difficult or impossible to select/copy from/open links in the alt text.

Here's Why You Shouldn't Leave Old SSDs Unplugged For Too Long - SlashGear

SSDs may be faster and have fewer moving parts than hard drives, but one thing they're not good at is data preservation. Here's why and what you can do.

SlashGear

David Amador Feb 6

@sodiboo sorry about that, thanks for posting it for me 🙏

@djlink

@djlink I mean yea, but both are not ok for archiving, you actually want them in a live enclosure, preffereably with redundancy

Dave Rahardja Feb 6

@djlink IMO the only material proven to hold digital data for decades at this point is tape, as evidenced by the tape reels they keep finding in storage warehouses whose contents are successfully read back https://www.tomshardware.com/software/linux/recovered-unix-v4-tape-quickly-yields-a-usable-operating-system-nostalgia-addicts-can-now-boot-up-unix-v4-in-a-browser-window

I suppose HDDs can hold archival data, but there are way more ways for spinning discs to fail than tape when stored for long periods of time. But maybe we can use magnetic microscopy to recover their data even if their circuits have died, their motors have failed, or their lubricants have died out. https://garnerproducts.com/hubfs/ucsd_recovery_of_partially_degaussed-hdds.pdf

Recovered Unix v4 tape quickly yields a usable operating system — nostalgia addicts can now boot up Unix v4 in a browser window

...with varying definitions of "usable," anyway.

Tom's Hardware

David Amador Feb 6

@drahardja they don’t make tech as they used to xD

Dave Rahardja Feb 6

@djlink Heh heh, I know you’re joking, but I think the engineering balance has shifted. We want faster access, higher data density, smaller sizes, and fewer moving parts. Data longevity beyond 1–3 years of non-use is not even a selling factor any more.

keith Feb 7

@djlink @drahardja i hear books have an amazingly long shelf life. that gutenberg dude was quite the archivist.

mossman Feb 6

@drahardja @djlink tape storage has its own risks due to the fact it's exposed to the elements. I've heard of cases where audio tape gets mouldy, flaky, sticky, magnetised / demagnetised, disintegrates, unrolls, crinkles, etc.

Dave Rahardja Feb 6

@mossman @djlink Oh for sure. But given *the same storage conditions* I’ll put my money on tape lasting longer than HDD, SDD, or optical drives.

mossman Feb 6

@drahardja @djlink I'd imagine you'd need more controlled conditions for tape than the others - they probably don't care so much about temperature, humidity and magnetism. Memory is basically impervious to everything except time and electricity.

@mossman @drahardja @djlink
Magneto-0ptical is the best easily re-writable for stability but due to lack of capacity went out of fashion by the late 1990s. I think about 256M for 3.5". I presume minidiscs are the same stuff, so likely to outlast "mix" cassette tapes and MP3s on SD cards.

Leeloo Feb 7

@drahardja @djlink
If you make that paper tape, true. Though I believe punch cards are tougher.

Magnetic tape rests against itself, which for audio tape results in an audible echo building over time, but presumably digital tape drives ignore the echo until it reaches a certain level.

Paper tape and punch cards have no such problems.

Frang

Feb 7

@drahardja @djlink carved stone walls have also shown to have good data retention rates

Dave Rahardja Feb 7

@frang @djlink I wonder how we would design a high-density, millennium-scale data storage device. I think holographic crystals show promise, because they degrade gracefully when damaged (every piece encodes most of the data), but they may be hard to read by future archeologists.

Without holography, the next best thing may be literal punch cards made of some sort of non-corroding material, maybe some metal alloy, ceramics, or even plastics, with through-hole punches using a high-density encoding with error correction to withstand damage.

Or maybe something encased in amber? Amber seems to have been able to preserve minute biological evidence for millions of years.

@djlink that is a very poor-quality source; modern SSDs indeed hold data for years, and powering them also doesn't increase data retention; they're not in any technical sense related to static (which needs constant power, very little) or dynamic RAM (which needs refresh cycles every few milliseconds).
You can be pretty certain that a not end-of-write-life SSD will retain data for years to decades. If you care, some SSDs actually specify more than just a overall MTBF (often in the 10⁶ h)

@djlink I'm not even sure where the myth that powering on helps data retention comes from; the last thing an SSD would want to do to increase data reliability would be doing any writing in the background.

@djlink note that yes, there's JESD218, but that specifies a lower limit (and indeed 1 a) for powered off data retention at the point in time when your SSD has reached its specified write volume; yes, electrons tunnel out of flash cells' gate capacitors, but as long as you've not written these to the end of their capacitance (erasing&rewriting makes these capacitors worse), this can all be accounted for by the SSD itself.
(the powering off is not a penalty to the SSD! Just the test condition!)

Mans R Feb 7

@djlink @funkylab High-density multi-level flash does fade over relatively short time. When powered on, the controller does periodic scrubbing of blocks that haven't been accessed recently, fixing any that have too many (correctable) errors. If left too long (a few years), errors will accumulate beyond the correctable amount and you lose data. This is not a failure of the device and is thus not reflected in MTBF figures.

Single-level flash lasts longer, typically at least 10 years.

@funkylab @djlink
Not powered off they don't.
An HDD can wear out with use but 25 years is easy for storage in a drawer or box in the attic. Floppy storage is far trickier.
Tape needs carefully stored.
Pressed DVDs* and especially pressed CDs are OK, but "written" ones can fade in daylight.

[* Assuming no manufacturing defects]

@raymaccarthy @djlink Ray, I'm sorry, but do you actually understand how flash memory works? powering on the SSD does exactly *nothing* to the cells until you at least read them (in which case you get a slight read wear on the cell and its neighbors), and you won't increase the charge levels inside a cell unless you erase and rewrite it, which does more damage, so the speed of charge leaking is higher than if you've just let the data alone.

(I mean, you're an EE – so model your gate capacitor!

@raymaccarthy @djlink … the charge it holds is your bits (mutliple, because on most SSDs these days you get more than two states); the only way that loses data is by tunneling of charge through the dielectric, which follows a shot noise model. Information-theoretically, we call this a "Z-channel", because you can only get from higher to lower states, never the other way around.
Now, if left alone, a couple of these bits will actually flip – that's why there's extensive forward error correction –

@raymaccarthy @djlink but as long as the number of these high->low state degradations is small enough, that's correctable. Flash memory is already, without long-term storage effects, a lossy medium, which you have to design your error correction for!
So, when an SSD manufacturer designs that error correction (namely, which code to use, and thus how many bits per information word to add as redundancy), they have to design it in such a way that at some erase-write cycle reliability they want to

@raymaccarthy @djlink sell to the customer. But that same redundancy that helps when cells' dielectric layers degrade due to repeated high-voltage "zapping" (right, you apply a high |E| to the cell to implant charge in flash memory!) and doesn't hold charge as well also helps with long-term storage. Just that the effect of "time and temperature", as you can imagine, is a lot smaller than the effect of "make that dielectric experience what would be called a breakdown if it was macroscopic"!
Hence

@raymaccarthy @djlink I'm really not sure where the idea that a powered SSD would be more reliable than an unpowered one – that could only be true if it would be re-writing itself in the background, which would, counter to the intent, make it wear out faster, unless the SSD is essentially unused and the re-writing was free to use arbitrary much rarely or never used pages to copy the data to. But even that would be very undesirable – who wants an SSD with a standby power usage as if written to?)

@funkylab @djlink
No, the main point is that an unpowered SSD isn't reliable compared even to floppies (though they are sensitive to storage conditions). I've had difficulty with 20 to 40 year floppies due to poor storage.
I transferred the MFM HDD contents to IDE HDD over 20 years ago. They are gone.

@raymaccarthy @djlink you must have had fantastic floppies, mine failed all the time; and I mean, the bit flip probability of 1.44 MB floppies, that's several orders of magnitude worse than that of an SSD even on undisturbed readout! I meanv how many bit flips do you think you'll see when you read 1000 freshly written to floppies? Certainly more than one! you can read that much data from an SSD in less than a second - and it will with probabilities of much better than 1 in 10⁶ have no bit error.

The Penguin of Evil Feb 7

@funkylab @raymaccarthy @djlink Modern SSDs do patrol scrubbing so they do indeed rewrite bad information or marginal data when needed.
Spinny rust has btw done the same thing for many years too, some spinny rust is even smart enough to relocate data behind your back so you don't even find out about the bit of the disk that's getting dodgy for some reason.

Ray McCarthy Feb 7

@etchedpixels @funkylab @djlink
SMART reporting on HDDs should reveal lots. Most Linux distros have a tool already installed to read SMART data and test HDDs.

Anthropy Feb 7

@funkylab Honestly you come across as condescending with your posts. Please don't.

- Trimming, voltage drift scrubbing, and wear leveling will cause data to constantly get re-written.
- While Single Level Cell NAND can hold your data for a decade, QLC can lose data within 1-2 years when left unpowered.
- Controllers are aware of this and can counter this if they're powered.

Example sources:
- https://www.xda-developers.com/your-unpowered-ssd-is-slowly-losing-your-data/
- https://www.seagate.com/files/staticfiles/docs/pdf/whitepaper/tp618-ssd-tech-paper-us.pdf

SSDs are leaky capacitors.

@raymaccarthy @djlink

The unpowered SSDs in your drawer are slowly losing your data

SSDs aren't ideal for long-term data storage

XDA

@funkylab @djlink
There are no ideal options for SSD. That's why I have backups and the user data on my workstations and main laptop is on HDD (conventional, not shingled or helium etc). The OS is easily installed and restored from backup on a new SSD.
The point is that an unused conventional HDD will last for decades. That's unlikely for SSDs or any high capacity SD card, USB stick etc.

@raymaccarthy @djlink I honestly find the opposite to be the case - HDDs can expose mechanical degradations (air barriers, motor bearings) that tend to work against you when you leave them unpowered. But this isn't about HDDs; it's about the myth that powering on an SSD will help data retention.

@raymaccarthy @djlink and again, it's pretty likely that a not overly written to SSD does indeed retain data many years; it gets problematic only when close to write volume limits. I feel like I've explained that already.

@funkylab @djlink
NO, the article isn't about powering up SSDs, but they fade in a drawer.
It's proven that HDDs generally don't wear out when powered off. The bearings etc only degrade when they are spinning.
The big plus on SSDs is random access speed, not reliability, for a home user. They are not a backup medium. An SSD in an external USB box is useful for file transfer, not backups.

@raymaccarthy I was reacting to @djlink post, not the article whose authors will never read this.

@raymaccarthy @djlink the statement "if left unplugged" is at best misleading (but really, just a misunderstanding) because data will fade regardless of the SSD being powered or not. And the cited 1 a data retention is also a misunderstanding of test conditions, as overly extensively explained.

@funkylab @djlink
Backups that don't use SSD, helium or shingled HDD etc are good.
I used to have tape but it's easier now to have multiple HDDs in USB boxes.

@raymaccarthy @djlink that's because of cost per bit, not because of reliability.

@funkylab @djlink
There were notoriously unreliable tape cartridge systems. Travan?
Customers hated the cost and time to do backups and our insistence that without the time consuming verification how did they know it was a backup?
Also hard to get customers to accept that RAID 1 or 5 was for high availability, that they STILL needed a backup. Ideally also extra copies off site.
I still have an external SCSI tape drive in the attic. It would need about 500 tapes for one backup.

@raymaccarthy @djlink yes, I understand you have extensive experience in long-obsolete storage tech.

@funkylab @djlink
Well, you never know who is reading stuff. Or linking.
Some of the ideas in Project Xanadu were interesting.
Anyone remember Bubble Memory? I think a Grid laptop with Plasma screen had it and one was used on a space mission. Didn't Shuttle have 8" floppies?

@raymaccarthy @djlink now you're just listing obsolete storage technologies, (I don't know project Xanadu) which all have many orders of magnitudes worse bit error rates than modern SSDs.

@funkylab @djlink
It's a matter of perspective. Certainly Zip drives were ghastly. I don't know how long term bubble memory was, but there is lots of stuff more reliable than consumer SSDs or 1T micro SD cards. Also the sudden complete loss of an SD card or SSD (256G to 1000 G) compared to errors on one file on a floppy (0.00144G or even 0.0001) are alarming.

@raymaccarthy @djlink you're following nostalgia there, not engineering. you need yo realize that all these ancient storage techniques never amounted to as much storage as your SSD. I'm not even sure there ever was a cumulative Gigabit in bubble storage, and if you read that out, it'd have several thousand errors. Much worse than an SD card left in a desk drawer for a couple of yeara, for sure!

@raymaccarthy @djlink "reliability" is measured in "errors per bit" and not in "errors per usual size of medium when the medium was new"