Production units are now shipping to users who did the EXCHANGE program.
I just did some testing with this MLC NAND Flash (MT29F64G08CBABA) and it has some very interesting results.
I wrote a file (25MB with very random data) and then did a verify:
Doing another verify produced this:
And you might think there is a problem. But you would be wrong! Its actually working as designed.
When you start getting into MLC (2-bit per cell) or higher, you will start to realize why MLC has major flaws: its unreliable. This is where ECC (error correcting code comes in). If you take a look at the datasheet:
40-bit ECC per 1KB~ of data! To put that in perspective, a typical SLC NAND has 1-bit to 4-bit per 512 byte. What this means, is per 8KB block, you will also need to write over 512 bytes of just ECC data to correct that 8KB on read back!
In the coming weeks I will be researching and working on ECC schemes used on more high end density MLC NAND devices.