Reply to: looking for indestructible backpus

[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

[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]

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

[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.

[MarillionFan]

Do you mean this 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).

[CaribbeanPirate]

The modern version of MrsGoof suggestion is to spray paint it on a wall on a chav estate. The time it takes for the council to clean it up is longer than the life of a CD.

[dmini]

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.

[DaveB]

If you really want long term data retention then Magneto Optical is the way to go for very long term backup. 20 years+ data life. Well known and reliable technology that has been around for 20 years itself. I've used it in the past and been able to retrieve data from up to 10 years previous without problems.

[TheMonkey]

Even the best CDRs die quite quickly. I've had some extremely good Ritek ones die after 3 years. Also there is that nasty bacteria around that eats the metal substrate apparently.

You need good old DLTs. I've seen data come off them after 15 years quite happily even after being stored in a box at around 37oC in the sun for that time!

Keep photos on good old fashioned photographic paper. It's the most proven medium.

[Ardesco]

Completely OT but I intially read the title of of this thread as:

Looking for Indestructible Bagpuss

I think I need to go home and have a few bevvies tonight, work must be getting to me

[expat]

Given that the internet is the cave wall of today, why not upload them to a website such as Flick? Then they'll get backup up for you by Google and others.

If they are private photos then take measures to protect them, otherwise do as the cavemen did and let anyone have a look.

Always good as an extra measure (as are any working copies that you happen to have made on the way). And keep the stuff (I'm assuming non-confidential) on your hard disk when you replace it, and put the old one in the attic. Just in case.

But I wouldn't trust any online service with my ultimate backups, unless it cost enough to give good attention, including refreshing reliably. And if you mean they'll get backed up by Google's index of images, they won't: the full-size image is the original, when it's gone, Google's link to it fails.

[PRC1964]

Given that the internet is the cave wall of today, why not upload them to a website such as Flick? Then they'll get backup up for you by Google and others.

If they are private photos then take measures to protect them, otherwise do as the cavemen did and let anyone have a look.

[expat]

I've just got out some CD's that I burned in 2001 and some of the data on them has become uneadable. (Nothing important missing, thankfully.)

But now that I've gone over to digital photography I need an affordable way of backing up my personal pictures that is completely indestructible.

CDR's (and presumably DVDR) don't seem to meet this requirement and having lost the contents of a hard disk in the past, that doesn't either.

Anyone got any ideas?

TIA

tim

I have looked quite a bit at this, and there is no easy answer. My best practice is:

Get a CDR's worth of data together in a directory.
Generate a CRC file on it.
Burn it to a CDR, with verification.
Burn it to a 2nd CDR, with verification.
Verify the CRC on both CDRs.
Use 2 different high_quality CDRs: I use Verbatim Azo for one, and a gold substrate for the other. Be careful to get gold, not just gold-coloured: not so easy to find.

These are archive copies, put them in physically separate places and never touch them; except to check CRC every year or so. Any probs, go into panic mode.

CDRs are the best option so far. I have read that DVD+R is as good or better, but have seen no evidence. The good news is that CDRs are not now as susceptible to substrate separation and mould (yes!) as they were a few years ago. This CDR plan should keep your data until the next medium comes along, at which point you transfer it.

Mrs Goof is right on both counts: re_archive regularly (and have several copies with CRc so if you find one wrong it's not already too late.

And a completely different medium is a great safeguard. Cave paintings have lasted well. So have properly-stored silver-based images. Consider an archive analogue copy for important images.

[MrsGoof]

pictures on cave walls seem to last a long time

HTH

seriously, you need to re archive reguarly.