Optimizing Linux with cheap flash drives [LWN.net]

Optimizing Linux with cheap flash drives

Posted Feb 18, 2011 23:54 UTC (Fri) by ewen (subscriber, #4772)
In reply to: Optimizing Linux with cheap flash drives by zlynx
Parent article: Optimizing Linux with cheap flash drives

That's good news about the 2.5" SSD flash drives. From what I'd read to date it seemed like the better ones were using decent (random read/write performance oriented) algorithms, but the cheaper ones were still using a fairly naive approach (and, eg, getting much slower as soon as all the flash cells had been written at least once). Perhaps we're further along the "adopt the IO controller" curve this time than I thought.

As you say, the (physically) smaller devices (CF/SD/etc), especially at the low cost end of the market, are always going to be constrained by available processing resources. So maybe some sort of "direct media control" API is the most optimal answer at the low end, especially if we can avoid the worst of the "fakeraid" situation (one-OS-version-only binary blobs). (There's also a higher risk of bricking the drive if you're moving, eg, a SD card back and forth between something doing its own low level access and something using the higher level API and firmware access. But like the NTFS driver presumably eventually enough the details will be right that people can trust it. And embedded devices with, eg, internal SD, can mostly ignore that risk.)

Ewen

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Optimizing Linux with cheap flash drives

Posted Feb 19, 2011 9:03 UTC (Sat) by roblucid (subscriber, #48964) [Link]

I just can't see why or who in the industry is going to have enough interests in this to "make it so". These cards that I come across are intended for storing camera type output, creating jpg and avi files or in embedded Sat Nav systems (replacing DVD).

They may be slow (and especially on writes) but for intended purpose, they're quick enough, how is there ever going to be momentum to create a market standard to convenice the small minority "enthusiast" market segment, who want to "hack" around with the hardware.

The SSD drive manufacturers see peformance block I/O support for NTFS, ext3/4, xfs and eventually btrfs as a way to add value and differentiate their product. Any alternative to the ATA interface, requires widespread software & hardware support, perhaps it would have happened if Flash had the kind of marketing hoop-la & attention that CPU architecture receives. The fact is, MS tried Readyboost feature in Vista to allow flash drives for fast virtual memory, and it flopped horribly in practice as the drives weren't quick enough, and memory prices fell fast enough to throw RAM at the paging problem.

Now perhaps there has been an opportunity in smart Phones and embedded manufacturers wanting to avoid MS patent taxes on use of FAT; but again when I read around on reviews, noone talks about filesystem performance, they're getting excited by multi-core, to resolve possible latency issues which show up as "UI sluggishness". It seems again that either the performance of the flash drive is good enough, or they've mitigated the issues in products and that becomes part of the competitive advantage.

Without encumbunts needing it, who's going to develop "direct media control"?