There are low-level recovery tools like TestDisk and PhotoRec that come in handy for this.This article contains four parts including If you suspect a card may be getting flakey, or if you run into trouble reading a card, immediately create a backup of everything on the card. One SD card was read easily but another required intervention from SanDisk, but it was eventually read.īill Biggart's photos from 9/11 survived the collapse of the second tower on a CompactFlash microdrive card. An atmospheric research balloon crashed in the Pacific Ocean and was recovered. That said, it's not always easy to get data from a damaged card. Other incidents like plane crashes are hyped by SanDisk so much that, admittedly, I get nervous using other brands. In 2004, there was an incident (covered happily in a SanDisk press release at the time) where a photographer's compact flash card survived a bridge explosion where the camera gear was set up so close to the blast that it was destroyed, but the CompactFlash card survived. Five memory card formats survived being boiled, trampled, washed and dunked in coffee or cola. The memory cards in most cameras are virtually indestructible, found Digital Camera Shopper magazine. The 2004 BBC article Digital memories survive extremes covers an interesting study by Digital Camera Shopper on the durability of memory cards. I recall reading (not sure where) about re-energizing cards by occasionally inserting into a reader. SD cards are rated to hold data at something like 10 years sitting idle.Use FAT32 instead of a journaling file system (like NTFS), which will write more often.This consumes write/erase cycles and shortens the MTBF. Write cycles are important, but MTBF (mean time between failures) is often 1M-2M hours or more, factoring in advances such as wear leveling, bad-block marking and management, etc. CompactFlash and SD/SDHC cards are designed to automatically and transparently map out memory cells that go bad, or in some cases when they reach a predefined limit. The good news is that their lifespan is usually measured in the many, many thousands of erase/write cycles, and that card controllers use an algorithm that balances the wear across the entire card's cells. Individual flash memory cells have a limited lifespan. Rob Galbraith, who maintains an amazing website on CompactFlash and Secure Digital cards, says I recently ran a cellphone through the washing machine (it was so dirty), and the 2 GB microSD card works just fine in my new phone (I eventually got the washed phone working too, but it was a good excuse to upgrade). In my experience, memory cards are quite durable, though occasionally finicky when it comes to formats. They are expensive compared to conventional CD-R. Data retention on this type of CD is expected to be intact even after 300 years. The storage medium on the disk is a thin layer of 24K gold so it will not oxidize. The best medium for long term storage are ARCHIVAL GOLD CD-R or similar brand. After 5-10 years, the contrast dye will fail causing read errors. I have seen FLASH memory with 20% corruption after 10 years of sitting in storage.įLASH thumb drives are great for transferring data from one computer to another etc, but NEVER to be used for long term archival storage. guaranteed you will have corrupt data when you try to use it. So a FLASH memory card put into a safety deposit box for 25 years. Same applies to FLASH memory cells, they require "recharging" periodically to maintain proper charges which represent data bits. As you know, any battery new in the pack sitting on a shelf for years will eventually discharge. FLASH memory cells are like millions of individual microscopic batteries that are charged at different levels. The FLASH memory chip itself is extremely rugged and can offer hundreds, if not thousands of years of service as long as maximum write cycle lifespan has not been exceeded. Same would apply if you wanted to use the SD card as long term storage. So you must refresh FLASH memory data periodically to ensure continued integrity. Re-FLASHing the firmware restores the chip for another 5-10 years etc. Many FLASH micro-controller applications are failing after 5-10 years because of FLASH memory corruption. most common in use as it is the cheapest to manufacture (double capacity). High density FLASH where one cell can represent 2 bits has greatest failure rate. High temperatures will accelerate the dissipation and shorten storage even less than 5 years. The voltages stored in the FLASH memory cells dissipate and can be misinterpreted after a while. My experience with FLASH is integrity begins to falter in as little as 5 years. Never trust FLASH memory of any kind for long term storage.
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