Anyone know of the best way to store data for safe/secure keep, where temperature and humidity could\would be an issue. I have a bunch of data that I dont want on some online storage location ( taxes, financial documents, inventions, etc ), but yet an onsite backup isnt good enough if for example if my home burned down etc. I have been using DVD's to store this data, but I noticed that the disc's after 4 years in the trunk of my car are showing signs that humidity is eating them away at the outside edge where the the aluminum is sandwiched between the 2 plastic layers and there is a grey/black corrosion happening. Since the data starts on the inner track and works its way out towards the edge as the capacity of the disk is used during the burn process, I am guessing that if I burned say just 4GB of the 4.7GB capacity that I could just rotate this set with a new clone of these disc's every so many years, and the .7GB space would be area that I expect to errode from humidity etc.

BUT... ONE thought I had is to do away with the disc's all together by cracking open a 16 or 32GB thumb drive and dip the entire PCB into epoxy to make it immune from humidity to everything except for the 4 conductors of the USB 2.0 jack which are generally gold plated, and would not be dipped. But I haven't gone to this extreme yet. In my area temperatures can dip as low as -30F on a RARE winter occasion, and I am not sure if thumb drives hold up under this kind of extreme cold or not for both data integrity as well as functionality. Could one be erased for example under extreme cold. I suppose the best test may be to take one of my cheap 1GB sticks, get a checksum of it, subject it to extreme cold via Dry Ice etc, and then perform a checksum test afterwards to see if the data is 100% or there is some or total data loss.

For some reason etched aluminum on a CD or DVD seems safer under extreme cold than flash chip(s)

I suppose I could buy a $40 small document type firesafe and bore a hole into its side and mount a laptop hard drive into it with a USB cable protruding out of it in which inside one of those USB to SATA adapters powers the drive and allows communication with it. Temperature and humidity extremes would be gone if stored in my home. And if there was a fire it "should" hold up if it protects paper documents, it should protect a 2.5" laptop hard drive. The hole would be plugged with the same clay looking stuff that wire rats use between rooms when running Cat5e/Cat6 between rooms with firewalls to keep fire from spreading from room to room via wire/cable ways. This stuff should keep the hot gas from a fire from getting inside the safe.

Online I have seen firesafe's with SSD's mounted in them, but they are more expensive than what I want. I am guessing that encasing a thumb drives PCB into epoxy and keeping the jack exposed might be my cheapest best bet with it stored in my vehicle somewhere safe, but figured I'd open up a discussion on this to see if there is a better method.


There are somewhat specialized "archival" DVDs that claim to last 50 years.

As for flash drives, Heat and cold don't cause electricity to flow so I don't see how they could be responsible for loss of data on a flash drive. Obviously I doubt they will hold up to absolute zero or the surface of the sun, but I'd wager that they won't have problems coping with the temperature ranges that the Earth's climate can put out. Quote from: BC_Programmer on October 26, 2012, 04:42:55 AM

As for flash drives, Heat and cold don't cause electricity to flow so I don't see how they could be responsible for loss of data on a flash drive.

Data Retention Time
A common concern with nonvolatile erasable memories is data retention. As explained in Section 3.1.1, over time, the floating gate charge is reduced due to leakage introduced by oxide defects. With higher temperatures, leakage current increases and, thus, the charge on the floating gate is reduced more quickly than at lower temperatures. This temperatures dependence follows the Arrhenius equation:

(1)

Where
AF = Acceleration factor
Ea = 0.6 eV = Activation energy
k = 86.17 × 10–6 = Speed constant
T1 = Temperature 1 (K)
T2 = Temperature 2 (K)

The Arrhenius equation gives an acceleration factor (AF) for data retention based on a temperature difference. Because it would take too long to MEASURE a data-retention time at 25°C, these measurements are done at a much higher temperature to accelerate the process. In the data sheets of MSP430 devices, data retention is specified to exceed 100 years at 25°C (77°F). This value is industry accepted and all vendors specify 100 years as the flash data retention duration at 25°C, despite it being extremely conservative.

Further tests show the exact number of years at 25°C is 1324 years.

[...]

At 50°C, (122°F) the data-retention time is reduced to 16 years only.

The safe accommodates standard size hanging file folders (not included) and is rated for a 1/2-hour fire protection for items such as CDs, DVDs and USB drives up to 1550-degreess Fahrenheit.