1) Time/Date 04:30 PM / 05/23/09
2) Response time 4 hr
3) Product MC50
4) OS Version
5) Clarify Case # - 1889388 Austrailian Support Desk is asking question for Korean customer who has a deadline. they are asking
We have one additional question regarding the life cycle of erase/re-writing.
Would you please obtain hardware spec from terminal design team?
We need such as following information.
For example :
Flash memory is possible to work XX days if erase/re-writing operation occurs XX cycles (times) per day, etc.
I understand that the reliability is minimum 100,000 erase cycles per block from your e-mail.
However our customer requires rough durable years. they need your answer till next Tuesday. Is it possible? They also asked today Our customer would like to know if wear leveling function works with "Dynamic" or "Static" system.
4 Replies
Thank you for your response. I have forwarded your response to the Australian Help Desk.
what are you asking?????
they want to know what the lifetime of the flash cells are in terms of read write cycles. and if wear leveling function works with "Dynamic" or "Static" system.
Ok, rating of flash is measured in erase cycles, not read/write cycles. I believe they're guaranteed for 100,000 erase cycles. With that said, you can read forever, that's not a dependency. Writing is a different story. In order to change 1 bit, the entire block (4K) must be erased. So, the way it works is this: the flash driver reads the 4K. Manipulates the data that's changing. Then it erases the block and writes the entire block back to the flash. So, in order to determine the number of write cycles, it depends upon how often the application writes data and how much data. The flash driver tries to be smart and it will only write a block back to flash when a new block is accessed. So, if you change the same memory location 10 times in a row without accessing another block, then there will only be one erase and write. I don't know what they mean by dynamic vs. static. The wear leveling algorithm is proprietary so I can't give the details. But, in summary, there is a counter that keeps track of the number of cycles on different blocks and tries to allocate physical blocks such that the counter on all the blocks stays close to the same. This is done as the flash is being used, it's not something that happens in the background.