FTL in consumer flash devices

FTL in consumer flash devices

Posted Jul 24, 2008 18:05 UTC (Thu) by brouhaha (subscriber, #1698)
In reply to: UBIFS by Cato
Parent article: UBIFS

In the "consumer flash devices" you cite (SD cards, USB sticks), the FTL is entirely embedded and hidden inside the flash device itself. That's also true of MMC cards and CF cards. It was NOT true for so-called "SmartMedia", but that died a well-deserved death. I'm not sure about some other types such as Memory Stick and XD cards.

Filesystems that work with such devices are all the normal Linux hard drive ones - ext3, JFS, XFS, vfat - but they are wholly dependent on the FTL to work.

Acutually, the filesystems are wholly independent of the FTL. Brand X and Brand Y SD cards might have any entirely different FTL embedded in them, but ext3 doesn't know or care, because they present the same interface to the system.

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They're dependent on the FTL in the sense that if the FTL wasn't there, 
they'd ruin the card in short order. Their *code* is not dependent on the 
FTL, but their *proper functioning* is, exactly because they're not 
designed for Flash devices.