Bit Rot?

[adamchevy]

Does bit rot really exist? I have read that it may exist with eproms? Also, that disc based games break down over time and fail? Possibly caused by cosmic rays? Seems like a concoction of crap to me.

[Seob]

Bit rot does exist. I have a few cd-r disc i cannot read anymore. I also have a few normal discs that imcannot read anymore. There is a lot of discolouration in the reflective layer.

[fiddlepaddle]

I have cartridges that used to work but no longer do.

Disks have been known to be damaged by some of the inks that were used that, over time, caused problems. Other disks might have been made with plastic that yellows, or seperates from the inner layers.

 

I have a large collection of CDs (lots from the early '80s), and some of them generate many read errors, but only a very few have become completely unreadable so far. I suspect that over the next 30 years, many more will become unusable.

 

The life of a disk probably depends on the specific product and process used during manufacturing for that particular game. I've read that CDs were originally estimated to last 20 to 60 years.

[adamchevy]

That's too bad, especially for those with huge collections.

[Keatah]

Masked roms and roms with diodes should retain their info as long as silicon doesn't migrate, grow whiskers and crate internal shorts. My best guess is 200+ years or even more.

 

I believe CD-R is nowhere near as long-lasting as one is lead to believe. This is due to dye bleed and degredation. 10years, 15years?

 

Pressed discs are very long lived 100+ years, as long as they don't get a viral or bacterial infection.

 

CD-R/W maybe 5 years at best? Depending on the quality. Perhaps this is improved recently?

 

High density flash rom like in SSD and smartphones. Ahh this has got to be the shortest lived medium 10 years maybe? It all depends on the density, SLC MLC TLC QLC.

 

Floppy magnetic media - 40 years proven. 75 years best estimate?

 

Magnetic HDD - 30 years proven

[AtariLeaf]

 

 

CD-R/W maybe 5 years at best? Depending on the quality. Perhaps this is improved recently?

 

 

 

Crap, I've got 15 years worth of family photos and videos on various cd-rw or dvd-r's. I better go back those up to something newer. Any recommendations? External harddrive?

Edited March 6, 2014 by AtariLeaf

[Keatah]

As usual, 2 copies of everything at all times. Maybe try a 1TB or 2TB HDD.

I generally recommend last-year's density/price sweet spot. Bugs are worked out, there is accumulated field experience, the mfg process is refined, word gets out if a certain model is bad.. That sort of thing. For bonus points, you can rewrite/refresh it every few years.

 

CD-R/W nasty shit. I've had them go bad rather quickly, days, weeks, and then OTH I've got some going on 6 years. There seems to be a lot of factors that need to go right for long-lasting CD-R/W operations..

[+GoldenWheels]

It definitely exists on pressed DVDs as well, I can tell you that.

[AtariLeaf]

It definitely exists on pressed DVDs as well, I can tell you that.

 

What about pressed ham?

[+thegoldenband]

I run backups of individual filesets to DVD-R, and then duplicate them on an external hard drive whose folders correspond to individual DVDs. I also back up my HD to a dedicated external drive.

 

What about pressed ham?

 

I don't know, but steamed hams are pretty much immune, or so they tell me in Utica.

[BillyHW]

I've had old floppies go bad. More likely the drive will go bad and ruin the disk. I've had that happen. Arg!

 

I haven't had a problem with CD-R yet.

 

I've seen lots of hard drives fail. Luckily not one of mine, yet.

[Atariboy]

Laserdiscs can sometimes be hit or miss with certain releases, but no issues so far with any pressed CD's or DVD's for me.

Edited March 7, 2014 by Atariboy

[Dripfree]

So in a hundred years my cd collection will be garbage but my great grandson can listen to my vinyl?

[JamesD]

Some of the dyes used in CD-R disks darken over time so you it does not age well for storage.

Regular CD and DVD disks don't have the same issue but over time the plastic itself could discolor.

 

Magnetic media can be altered over time due to the magnetic field of the earth and gravity. It was common practice to rotate large magnetic tapes periodically for this reason. I think more modern tape is less susceptible than the older stuff.

 

Magnetic fields also weaken over time. I have seen some programs that refresh disks by reading and rewriting the disk contents but you couldn't do that with copy protected disks.

I think I was able to copy all of the contents of my old disks except for one disk when I backed them to new disks a few years ago. I backed up to new 5 1/4" disks and 3.5" disks. Sadly, I lost some cool animation stuff I did. The program was intact but the graphics files were corrupted.

[Rybags]

"Proven" on a given technology is not really any guarantee for future evolutions.

 

I've found the low capacity formatted 5.25" disks more reliable than the 3.5" 1.44 Meg and 720K.

 

HDDs are probably the same. With lower density there's a much greater surface area per bit so any degradation will take longer to have effects.

 

Optical - I've found DVD to probably be slightly more reliable, and generally have better chance of recovering data when there are errors than CDs.

[Keatah]

DVD's tend to "bronze", they darken in color due to oxidants trapped in the "plastic sandwich".

 

@RYBAGS

When I say proven I apply it to a specific media/drive combination. If I failed to mention it before I am mentioning it now.

 

In DVD systems I think you’ll find the laser is more precise and the materials are better, just because that’s what’s required to make it work.

 

You're probably right. My long-term floppy tests are applicable to Apple 5.25" 143K disks either written by the mfg/publisher or on a Disk II drive.

 

@ALL

So I got curious this evening. I broke out my test equipment and hauled it into my cozy loft.

 

I examined the field strength and pulse shape on 35-yr old floppies which were formatted and written by an arbitrary chosen Disk II drive back in the day. Not that I had a big selection to choose from - it was one of my first personal disk drives. Well, the raw shape and strength is still nearly perfect and identical to what a freshly-written-today disk looks like. I measured right at the head.

 

Only upon 10x magnification could I see some sloppines and loss of definition. And it wasn't a lot. And definitely well within pre-amp and pulse shaping circuit specifications. My BOTE calculations tell me that these test disks will be good for another 60-84 years. I observed what would be maybe a 4 or 5 percent degradation in read field strength vs. a freshly written today disk. I’m impressed! And I’m thinking if I properly degauss the Disk II head I could gain back a little bit more sensitivity. But I’m satisfied as is right now.

 

Remember the hype that floppies would not be viable long-term storage? Gotta think that was marketing pushing new stuff on you. Remember how they were telling you to replace them every so often and never ever count on them for long term storage? I’m here to tell you that’s hogwash when it comes to low-density floppies!

 

I’m not biased toward the old classic Apple Disk II drives or anything. I like them BECAUSE of how well they performed. It’s a good thing.

 

But, I would not trust 3.5" 1.44MB disks and 5.25" 1.2M disks. And ESPECIALLY NOT C64/1541 disks. I never really paid much attention to IBM 360K, Atari/Mac 3.5” 720K disks, nor the 810 5.25 disks so I can’t comment on those. I do know the C64/1541 disks were pretty bad, and the Amiga 3.5” disks were even worse! Piss on that godforsaken machine.

 

I tend to note that the simpler the circuit, and lower the density, the more reliable the disk subsystem is overall. Heh..what else is new?

 

@JAMESD

Without really thinking about it. I would periodically (every few years maybe) jostle and reorient my cartons of floppies. Including my dated and logged test disks. This came about because I’d reposition things in my collection or open stuff up to get at something. I also remember being given similar instructions for tape storage.

 

In data recovery, different wavelengths and polarizations are available to read discolored or nearly opaque optical media. In mission critical cases the optical surface (which is the final lens in the path) can be resurfaced.

 

There is equipment that can bypass scratches by reading at an angle. Think architectural photography, those tilting perspective lenses. Remarkable stuff! And you’ve got active optics which can help see through fogged discs.

[Keatah]

Allow me to add one more thing:

 

I never really worry about format and machine availability - the capability to read/write a certain medium. Different devices and systems and media fall in and out of favor all the time.

 

This gives anyone the opportunity to migrate from one storage technology to another. Besides, with commercialism and a bevy of new products constantly being released, Data Migration may be the one constant in an ever changing storage landscape. As part of maintaining your digital collection of whatever kinds of files you value it is important to keep them in an easy-to-access non-proprietary format.

 

Standards like NTFS, .JPG, .DOC, .TXT, USB are going to be around for years to come. If and when they die off, it ain't gonna happen overnight. If one type of storage device suddenly becomes non-kosher and isn't going to be supported anymore, it won't happen overnight. You will have plenty of time to conduct a migration operation or pay someone to do it for you.

 

This is one of the reasons why I tend to not rely on "photo organizer" type programs. I just default to the native file system utilities, e.g. Windows Explorer currently. The file name, or folder name, can contain all the necessary summary information. If that isn't enough there's always README.TXT files!

 

I've got shit from my KIM-1 and Apple II (cassette era) saved on a modern HDD. And throughout the years it's been transferred through several PC's and many classic systems. I'm sure CD-RW and Zip disks were included in there somewhere. Which, by the way, I am also conducting a long-term test of Zip-100 disks. So far I've got about 10 or 12 years logged.

Edited March 7, 2014 by Keatah

[tep392]

 

Crap, I've got 15 years worth of family photos and videos on various cd-rw or dvd-r's. I better go back those up to something newer. Any recommendations? External harddrive?

Mask ROM.

[+GoldenWheels]

 

What about pressed ham?

Hadn't heard that one in several years!

[jhd]

Does anyone have any experience with data stored on cassette -- either commercial recordings or self-made tapes?

 

Based on my (limited) experienec with audio cassettes, it really depends on the storage conditions and the. I've heard perfectly fine 40 year-old recordings that were professionaly kept in archival cold storage, and 20 year-old recordings with significant loss that were kept in completely uncontrolled storage.

[karokoenig]

 

And ESPECIALLY NOT C64/1541 disks.

 

There was a really interesting article in a recent issue of the german language retro magazine RETURN. It basically looks like many storage media are about to fail pretty soon. And it seems to happen fast once the process starts. I.e. my several boxes of C64 software I have neatly stored in a dry dark cool place might already be unreadable all by themselves.

[frank_c]

Out of the 400+ CD's I bought, I think only one has issues. A dark spot on one of the discs from the first Zeppelin box set. The disc skips on that spot.

[JamesD]

Does anyone have any experience with data stored on cassette -- either commercial recordings or self-made tapes?

 

Based on my (limited) experienec with audio cassettes, it really depends on the storage conditions and the. I've heard perfectly fine 40 year-old recordings that were professionaly kept in archival cold storage, and 20 year-old recordings with significant loss that were kept in completely uncontrolled storage.

I think the only problem I had with cassettes were some that were exposed to water and a few that were stored too close to a magnetic field at some point. Neither type were readable though I think it may be possible to read the first group with a little effort. I think the lubricant on the tape surface had been damaged.

I transferred most things to disk so I didn't really try more than once.

[Keatah]

 

There was a really interesting article in a recent issue of the german language retro magazine RETURN. It basically looks like many storage media are about to fail pretty soon. And it seems to happen fast once the process starts. I.e. my several boxes of C64 software I have neatly stored in a dry dark cool place might already be unreadable all by themselves.

I wonder what they base that assumption on? How do they determine any rate of decay? What brands of media? And what is pretty soon?

 

 

 

Does anyone have any experience with data stored on cassette -- either commercial recordings or self-made tapes?

 

Based on my (limited) experienec with audio cassettes, it really depends on the storage conditions and the. I've heard perfectly fine 40 year-old recordings that were professionaly kept in archival cold storage, and 20 year-old recordings with significant loss that were kept in completely uncontrolled storage.

I have some data tapes from Apple II era, 1978-1979. They seem to be fine. I also saved a lot of TRS-80 Pocket Computer type-in programs on a RadioShack minisette-9 tape recorder. Those were still readable as of 6 years ago. I'm not running a controlled scientific test on these. I didn't record exact times or dates or do a signal strength analysis. But they are stored nearby my floppy collection.

[Kyle22]

How about LS-120 SuperDisks? They are 120MB 3.5" floppies with optical laser tracking (floptical). I have some of them with data that I would like to keep.