looking for indestructible backpus

[expat]

So come on, what is the difference between the CDRs that we can buy, and those used by the recording industry? Those can last for years - and years!
I have ones well over 10 years old - no issue.
I'm intrigued, as someone was talking to me this weekend, about having lost lots of valuable photos off a CD, so it looks like this is becoming more common as an issue.

They're pressed, not burned. It's becoming more visible as an issue, as time passes and people find they can no longer read their disks.

The substrate- (or binder-)eating fungus is supposed to be less of an issue now since it was recognised and (basically) the layers stuck together better to keep the fungus out, but I'd still make more than 1 copy, check periodically, and refresh the good copy when the other was found to be bad.

As for "quality" of the CDR, I don't put much store in that. More important is the actual material used:

Firstly the dye. You want pthalocyanine dye (the best), or Azo dye (only slightly less good. Only available from Verbatim or Mitsubishi). Not cyanine dye, which is what you get on most CDrs.

A CDR-ID program can identify the dye from the coding on the CDR. I think that Verbatim, Mitsui, Mitsubishi, Kodak etc will tell the truth on these indicators. I wouldn't want to bet my data on all CDR manufacturers from all the world.

Secondly the reflective layer. It's gold, gold/silver, or silver. Gold is best: look on the bottom surface, especially near the edges. The top surface may be gold/coloured, but that's just to look good.


PS Shelf life of unused CDRs is surprisingly short. Don't stock up.
Don't open the package when you get it. Wait until you're ready to use it.
Store upright in jewel cases.
Sorage and handling is a much bigger risk to your data than materials, especially if you don't buy cheap (if you do, you'll get previous-generation manufacturing so you will still have yesterday's problems).

[MarillionFan]

Do you mean this backpus?

[LovemyGTI]

Archival CD/DVDs

I was looking into this problem the other day.

I do second one of the posters re Magneto Optical's attributes for retention (it meets ISO standards, etc). But with digital SLRs producing GBs each time you do a shoot, MOs are not very high capacity (max 9GB i think) and probably not cost-effective (9.1 GB media from £52.35 per cartridge!!!):
http://www.dvd-and-media.com/verbati...to-optical.htm

I looked at getting a DDS3 tape drive off ebay (2nd hand ones that do 24GB go for cheap but they only have SCSI interfaces which is a friggin pain in the age of USB and firewire). Data retrieval is also slow. DDS does not meet ISO standards but they are still WAY better than average CDRs)

These CD/DVD media are supposed to last 100 years (I doubt they'd actually stand up to any real ISO standards for retention):
http://www.delkin.com/products/archivalgold/index.html


I read on dpreview.com forums that the most cost-effective is to invest in a RAID storage in your home/office. Unfortunately, they miss the point of putting backups offsite...

Back to the drawing board and pray my external firewire drive does go belly up.

[DaveB]

I was looking into this problem the other day.

I do second one of the posters re Magneto Optical's attributes for retention (it meets ISO standards, etc). But with digital SLRs producing GBs each time you do a shoot, MOs are not very high capacity (max 9GB i think) and probably not cost-effective (9.1 GB media from £52.35 per cartridge!!!):
http://www.dvd-and-media.com/verbati...to-optical.htm

Shop around and go direct to suppliers as a business and you'll get much better prices. MO cartriges will do up to 30Gb now as well. For commercial solutions the MB/£ ratio is actually very good compared to anything else apart from DVD/CD but for serious archiving these are barely any better than consumer grade stuff. MO is much faster than tape in read/write speeds and has the advantage of Random Access rathe than linear.

Admittedly the gear I worked with was in the multi-terrabyte bracket and cost several hundred thousand quid but the smaller units are much more resonably priced

[expat]

But with digital SLRs producing GBs each time you do a shoot....

Ahem, not to mention that a full colour 4800dpi scan of a 6x6 saves to a PSD of about 640MB. That's one picture.

[DaveB]

Ahem, not to mention that a full colour 4800dpi scan of a 6x6 saves to a PSD of about 640MB. That's one picture.

I was working on a project to store a historic map collection. 1200 dpi 32 bit colour GIF images of maps anything up to 12 foot long and 6 feet wide. The biggest single image we had before I left was just under 9gb