I think you guy will find this interesting.
http://www.amamax.com/acaan2safldi.html
http://www.amamax.com/acaan2safldi.html
build your own ssd
- Thread starter NES_player4LIFE
- Start date
SDHC cards have a very specific issue all with SSD devices in general.
They have a limited time of persistence for there memory.
To be precise the memory itself has a life expectancy of the data stored in it of ~10 years.
MLC (multilevel chip) technology goes between 5-10 years in endurance (IE keeping it's charge). SLC (Single level chip) technology has one of 10 to 40 years depending on size (the higher density the short life span of the data). This is one of the issues of NAND flash, is that it has become a poor quality device in terms of durability (IE you can't write more than 1000 times) before failure and the state of your data is questionable often as well.
Example Samsung SLC NAND is ten years so is there MLC by the way (Samsung is better quality) 100000 cycles WITH ecc (it requires error correct encoding to meet that number of cycles). The SSD cards last 10 years because they are the same technology.
NOR flash on the other hand
Macronix NOR flash for example is at 20 years.
You are probably now think "it will change so .. whats the big deal?" How do you know what will change and when it will change on your SSD? I have a system that's over 10 years old that boots an old version of linux. These are things you should keep in mind when you buy stuff.
The important thing is KNOW the technlogical limitations and keep your data and system safe. I'm right now attempting to read 10 year old CD's with limited success (yep securely borked up).
Oh and some flash is rated for 100years so 20 years is short for NOR flash.
Cyb
How do you plan on fixing it if it fails? Basically you need to use a raid systems on an ECC system then.
That's what I was trying explain. It hides the fact the data is slowly failing much like many IDE drives did a few years back. Windows would ignore 'small' errors on the hard drive and you had to have other software report on the condition of the system drive to find out when it would fail.
Google did a lot of research to save millions a year in system maintance to find out when the drives needed to be replaced before they needed to be. The same deal is necessary with SSD drives. How do you replace parts in it? In this case it's a CARD, but at the rate cards are being obsoleted there are starting to be issues with availability of reliable replacement media.
In addition to that issue is compatibility not all SD cards are made the same (literally speaking) because the hard ware varies and not ALL features are mandated. Especially on different form factors of the SD card format (micro SD is particularly bad for that).
Cyb