What is the best method for appending data to a file stored on a usb flash drive to avoid too many write cycles?

[SubmarineEd]

Thanks again Bob

As you say, most modern USB flash drives can be rewritten millions of times, but I don't even want to come close to this as my data is too precious.  Keeping backups and having multiple files splitting the data is the answer, I just have to dream up the exact scheme now.

The main thing I want to avoid is rewriting the same segments over and over, every sample period and it seams that the way FAT works this isn't a problem as the bytes are daisy chained together.  I accept the need to rewrite the EOF when I append more data, but the EOF has then moved to the new end of the file position and therefore it will be a different segment being rewritten each append as the data set gets bigger - brilliant!

Thanks and regards

Ed

[AKA_TG]

Monitoring this interesting thread brings up a minor side question in my head.

I have heard (From an IT guy) that Most USB drives when reading data off the drive are actually writing to the drive even when they are only

reading the data.

He said at the level where the binary 1's and zero's are stored in the mosfet transistor (or whatever it is called today) must be reset to the state that it was in before being read. He said sometimes (not always) the act of reading the state will change the state (perhaps drain it) after the read and therefore the state

information just extracted from the mosfet (1 or 0) must be re-written on to the transistor mosfet whatever its called so as to be 100% reliable.

Anyone have any thoughts on this?

Thanks

[SubmarineEd]

Hi

I'm not sure about writing when reading and would also be interested if anyone can point me at an article or document which explains it.

I have read about the 'read disturb' action, but from what I read its the neighboring blocks that may loose data after thousands of reads of a particular block.  The flash drive controller should count the writes to any block and rewrite the data to neighbouring blocks if the count gets too high, avoiding any losses.  If I understand this correctly, it means that there should be a single rewrite for a thousand or so reads?  This is worth concidering but not as bad as performing a write with every read.

Many thanks

Ed