Long term study

[Ghitulescu]

Originally Posted by BassPig

Today, I tried to read two of these discs and the drive would not read them. I tried four different PCs and drives, including the one that wrote these two discs. Not one of them could read it. I just get a blank Explorer window in XP.

Get yourself an LG DVD Burner, the older the better (say 4040, or 4080, or 4120), then use Isobuster or isopuzzle and go on ... you'd probably get the most out of them.

[BassPig]

I tried three burners--including the burner that wrote the discs.

I finally ended up using a program "DVD Disaster" to attempt recovery. It took 49 hours and over half the disc was bad sectors. It created in ISO file, which I burned to a new DVD. That DVD contained now files, but only opened a blank Explorer window. So I guess there's no point in trying to extract data.

I am noticing that a whole batch of Verbatim and TDK DVD-R that I have are about a year old, sitting on the shelf, and burn speeds have deteriorated. These discs used to burn close to 16X actual speed in Nero. Now they are down to anywhere from 3.7X to 6.8X writing fresh data. So it appears that media is going back sitting in its original cakeboxes on the shelf.


All of this had me going to bed thinking about a more permanent solution to this... after pondering hard drives and tape backup, I got an idea about a new DVD burner design..

My concept would eliminate the dye entirely. If blank discs contained just an aluminum layer, perhaps with a coating on it that enables it to dissolve under intense writing power, a more powerful laser could burn real pits into the aluminum layer, thereby making a disc as good as a glass mastered disc.
Of course the challenge would be in cooling a laser of that power level, but I can conceive of this technology being viable in five years.

[mariush]

Why bother? It's like trying to invent a floppy disc or a better CD-ROM drive.

In a couple of years maximum, flash memory will be so cheap, you'd be able to get 16 GB memory cards for the price of a few DVDs. Then just copy the content of a dvd twice, make some PAR2 recovery volumes and you're all set. And maybe copy to system once every 6 months and write data again to card to refresh it in case it bitrots.

I can already buy 2 GB micro-sd cards at around 7$, or the price of 8 DVDs, and a 4GB card at 10$.

I'd say actually the problem is that when designing a medium, engineers should allocate more on recovery error and make the whole write/read error use it in hardware better - it wouldn't have hurt much if a 4.38 GB DVD had only 4 GB of actual data.

[CWR03]

Hard drives are already so cheap that I'm considering buying a half-dozen 1 or 1.5 TB hard drives and hot-swap drive enclosures to eliminate disks completely for storage. Good disks are about $30 US per 100, a 1 TB drive on sale can be had for $60. Adding $20 for a 5 1/4" bay enclosure with removable tray and the cost per TB of storage is a tad cheaper than with disks, and then instead of over 200 disks you have one small, transferrable unit.

[BassPig]

The idea is to create truly long-lasting media, to fulfill the promise that optical media manufacturers made, whose claims of 70-200-year lifespan for recordable media convinced some of us to believe in.

I don't like mechanical storage, because a hard drive can fail while in storage, from stiction or expired/dried out capacitors. It can also suffer ESD damage.

The same goes for memory sticks. I can't tell you how many times I lost an entire memory stick of camera photos while transferring it to my SmartMedia reader, only to find the reader and the OS reporting that the media needs formatting and my data was somehow wiped in the process of unplugging it from the camera slot and inserting in the reader slot.

I think it's not unlikely that a DVD burner could be developed that could write by actually melting pits in the aluminum layer. It would be necessarily single-layer, but the discs would never fade away unless they were exposed to intense heat, corrosive chemicals or kinetic forces sufficient to shatter the polycarbonate platter. It should be just as long-lasting as a glass mastered disc.

This really is a growing concern as I shoot 16GB of XDCam footage per day on average and long-term archival is a serious problem right now. Presently, we have a network of about 13 computers, each with a couple terabytes of storage and we distribute at least 3 copies of all new footage across the network while the project is in the editing/production phase. Once completed, we make a backup archive on dual layer DVD-R media and keep one copy on a USB 1TB external drive. But this is an unsustainable solution, as the growth of data exceeds the availability of storage capacity. We keep adding more 1TB drives to these computers, but once there are no more slots and no more controller ports left on any of the PCs, then we're forced to dump older material. Given my experiences with these two DVD-R single layer discs from Samsung/Meritline, my trust in long term storage via optical is severely shaken.

[mariush]

Did you look into tape drives?

A 400GB HP Ultrium tape writer is 1500$ and cartridges are about 50$ for 800 GB / 1.6 TB compressed (though it looks like you have to buy sets of 20 tapes)....

Now I don't know about the life of the tapes but I assume it's much higher than a DVD's, as they're inside plastic cases... (I guess assuming you'll keep them in a controlled environment)

...

I think such discs as you say don't exist probably because those pitches in the aluminium would cause the disc to vibrate a lot at the speeds inside a unit - a disc is spinned inside at several thousand rotations per minute so even a scratched disc in theory can expand scratches and vibrate itself to pieces...

[BassPig]

I gave tape drives consideration, but cost, lack of speed, lack of accessibility and dropouts/data loss are concerns, as is the cost.
Presently, we're amassing a large number of 1TB USB ext drives, but it's getting messy fast.

Re: the pits in aluminum, shouldn't be a problem burning these and certainly no worse balance than glass-mastered discs. The burning would not change the mass of the disc at all. It would more likely discolor the portion of aluminum being written with 0's, for instance. Mass of the aluminum would remain constant. Nothing being taken or added to the disc. Polycarbonate is pretty strong stuff. Have seen loads of badly-scratched DVDs play just fine and never shatter. It's not ceramic or quartz. The only applications I know of where scratches can be a fatal issue is on UHP lamps used in projectors because they operate at 200 atmospheres and 1900°F and even a small scratch in the quartz will cause a strain that will shatter the bulb. No such problem with polycarbonate DVD discs.

[Ghitulescu]

The only LTS solution I'm aware of is the "recopy" method, now that one has digital data is easier as it were with analog items. Just COPY/PASTE from a support to another one.
It's the law of the nature that everything rots. Sooner or later.