CompactFlash, SD, MMC, USB flash storage. Anything that does not have moving parts inside.
February 6th, 2017, 7:22
my memory card of 32gb not formating with windows. i was using this card in my ip camera for recording. now it is not useable in windows. please help.
February 8th, 2017, 2:27
try formating with rufus..
try buying a new card..
February 13th, 2017, 12:57
COPY EVERYTHING FIRST
Check the data is good, if it is crap, then it may be a fake or has failed.
Once you are happy you have your data, then
Try Diskpart (Built in to windows since XP) - You can remove the existing partition with override flag set.
Then you can create partition. If that wont do it, return it to shop. If you bought it on ebay .. dont. Probably a fake.
February 13th, 2017, 19:17
Just a question ...
Do any tools align the FAT32 root directory and cluster size to NAND pages or blocks? Do the flash controller manufacturers' tools do this?
February 14th, 2017, 6:43
I wouldn't have thought so, the host operating systems usually determines the block size. But could be worth doing some experiments with different block sizes, I cant see there being much difference as the internal speeds of these are probably considerably faster than the interface. That said, I have seen some big gaps to the boot sector from MBR//PT - never really gave it much thought why they do that.
February 14th, 2017, 18:03
http://wiki.laptop.org/go/How_to_Damage ... age_Device
This page tells you how to degrade the performance and reliability of FLASH-based storage devices like SD cards and USB drives (pendrive, etc). And by implication, how not to damage them.
Putting it Together
How is the filesystem layout relevant to our problem? Allocation data accesses are very common, as are cluster-sized data writes. So we want those operations to be efficient. If the allocation data starts on a NAND FLASH page boundary, a given allocation map write is less likely to span two pages, so the FTL gets to do things the "easy" way, which is faster and causes less NAND wear. If the cluster size is a power-of-two multiple of the NAND FLASH page size and the first cluster is aligned on an erase block boundary, cluster writes are similarly "easy".
Conversely, if the layout is bad, every cluster write might "split" two pages, forcing the FTL to perform four internal I/O operations instead of one.
The manufacturers of FLASH storage devices understand this. When they format the device at the factory, they know which filesystem they are putting on (typically either FAT16 or FAT32), the page and erase sizes for the NAND FLASH chips inside, and the characteristics of the FTL software in the internal microcontroller. (Actually, there is yet another factor - multiple NAND chips or multi-plane chips can further influence the locations of "efficient" boundaries.) Knowing this, they can choose a layout that encourages "easy case" internal operations.
Here is how the factory formatted my Toshiba flash drive.
From the boot sector ...
Reserved Sectors 624
Bytes per Sector 512
Sectors per Cluster 64
Big Sectors per FAT 3816
These are the locations and sizes of the various components of the FAT32 file system:
boot sector at LBA:8064
624 reserved sectors
FAT#1 at LBA:8688 (= 8064 + 624)
FAT#2 at LBA:12504 (= 8688 + 3816)
root dir at LBA:16320 (= 12504 + 3816)
The boot sector begins on a 32KB boundary (8064 / 64 = 126).
The root directory also begins on a 32KB boundary (16320 / 64 = 255).
The cluster size is 32KB (= 64 x 512 bytes).
It appears that the manufacturer has inserted 624 reserved sectors between the boot sector and FAT#1 (rather than the usual 32 for a HDD) so that the root directory is aligned.
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