What took them so long?

Ssds: SanDisk’s New Flash File System Improves SSD Write Speeds by 100 Times

To maximize random write performance, SanDisk developed the ExtremeFFS flash file management system. This operates on a page-based algorithm, which means there is no fixed coupling between physical and logical location. When a sector of data is written, the SSD puts it where it is most convenient and efficient. The result is an improvement in random write performance – by up to 100 times – as well as in overall endurance.

What this sounds like is using a mostly-random-access device (which a SSD is, as opposed to a spinning disk, where access time depends enormously on physical layout) like a — gasp — mostly-random-access device.

It’s funny, because the code for managing spinning disks works very hard to disguise the essentially serial access nature of the devices — buffering, optimization so that data that are likely to get read or written together will be stored on nearby tracks, so on and so forth. Now Sandisk is writing a whole bunch of code to hide the essentially random-access nature of SSDs from the code that tries to hide the serial nature of spinning disks. (There’s a chance they’re cutting out the middleware, but I’m not betting on it.)


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