 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : SD card life
| Author | Message | ||||
jebz Regular Member  Joined: 13/06/2011 Location: AustraliaPosts: 79 |
Has anyone pushed the SD card endurance to the limit? If I create a new file on the card each day then write to it each minute how long can it be expected to last? Hopefully more than 70days (100,000/60/24). Does closing then reopening the file after each record have a significant effect? |
||||
crackerjack Senior Member  Joined: 11/07/2011 Location: AustraliaPosts: 164 |
See this link as a starting point. There are many variables, not least of them being the make of the card itself. But 100000 writes is quite a lot. There are however 86400 seconds in a day, so you could reach the endurance limit quickly... |
||||
| mookster1 Regular Member Joined: 10/06/2011 Location: New ZealandPosts: 81 |
Hi Jebz As I understand it there are several factors involved in determining just how many read/write cycles an SD card will endure. Flash memory generally only has a R/W endurance (really write endurance; you can have an incredibly huge i.e. much bigger than 100,000 cycles) of about 1000 cycles but the clever way the SD card deals with this is by "spreading" out data over several, completely unrelated cells. Each read/write means that that data is written to a new set of cells. This works really well if you've used up less than half the space on the SD card. However when there is little or no space left on the card then you get figures near 1000 R/W cycles for the entire card. Closing the file (to my knowledge) just writes the data to the SD card, so closing and opening the file again (AS APPEND) probably won't make much of a difference, but if you wrote a new file, this would probably increase flash wear. (BTW if anyone is reading this and sees obvious flaws in what I've written please correct it  )
Hope this helps Capacitance is futile - roll on 2012! |
||||
| ArtBecker Regular Member Joined: 25/08/2011 Location: PhilippinesPosts: 47 |
I did a Google search on "wear out an SD card" and got over 5 million hits. The bottom line is that it rarely happens. Forget about the numbers and statistics and hours stuff. They are essentially meaningless generalities. If your card does somehow fail, then spend the $5 to get a new one. Back up your data. Format an SD card as FAT, and not NTSF. You can use ScanDisk, but never de-frag an SD card. Since they have been invented, I have never had an SD card fail, and have had only one flash drive fail. |
||||
 Print this page |
