Jsem ja to ale “chytry” idiot, az ted me napadlo, zda je mozne si poridit Encyklopedia Britannica v digitalni forme. Zatim jsem nasel jen appku, ktera to umi prohledat online, ale ne, ze bych nechtel mit micro-sd kartu, na ktere by bylo vsech 800 000 hesel. Porad se mi nepodarilo zjistit, jak dlouho SSD disk/karty vydrzi na zivu, a to kdyz je zavru do prachuvzdorne, netemperovane a kovove krabicky...
Hmm, takze cca 5-10 let, ale daji se prepisovat stejnym zaznamem, a tim znova nabit... to by me zajimalo co udela dd if=/dev/sda1 of=/dev/sda1; musim to nacist a zkusit, podle me je to to co s tim jednou za cas chci udelat... tohle je hezke info:
Never trust FLASH memory of any kind for long term storage. My experience with FLASH is integrity begins to falter in as little as 5 years. The voltages stored in the FLASH memory cells dissipate and can be misinterpreted after a while. High temperatures will accelerate the dissipation and shorten storage even less than 5 years.
High density FLASH where one cell can represent 2 bits has greatest failure rate.. most common in use as it is the cheapest to manufacture (double capacity). Many FLASH micro-controller applications are failing after 5-10 years because of FLASH memory corruption. Re-FLASHing the firmware restores the chip for another 5-10 years etc. So you must refresh FLASH memory data periodically to ensure continued integrity. Same would apply if you wanted to use the SD card as long term storage.
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. FLASH memory cells are like millions of individual microscopic batteries that are charged at different levels. As you know, any battery new in the pack sitting on a shelf for years will eventually discharge. Same applies to FLASH memory cells, they require "recharging" periodically to maintain proper charges which represent data bits. So a FLASH memory card put into a safety deposit box for 25 years... guaranteed you will have corrupt data when you try to use it. I have seen FLASH memory with 20% corruption after 10 years of sitting in storage.
FLASH thumb drives are great for transferring data from one computer to another etc, but NEVER to be used for long term archival storage. Same goes for the conventional CD ROM. After 5-10 years, the contrast dye will fail causing read errors.
The best medium for long term storage are ARCHIVAL GOLD CD-R or similar brand. The storage medium on the disk is a thin layer of 24K gold so it will not oxidize. Data retention on this type of CD is expected to be intact even after 300 years. They are expensive compared to conventional CD-R.
What's the life expectancy of an SD card? - Super User
https://superuser.com/questions/17350/whats-the-life-expectancy-of-an-sd-card