On Sat, May 16, 2009 at 8:14 PM, NoiseEHC <noise...@freemail.hu> wrote:
> > > Sorry, should have explained myself better, as I was also talking about > memory speed and not size, this time. > > Ahh, if you wrote about memory size then never mind my comments. :) > > > Thing is, most flash controller implementations are crap, and it will > probably be the case with the one in Gen 1.5. I'm quoting 0.5MB/s in *random > writes* to the file system, nothing to do with compression. Most decent > SSDs can write at last 1MB/s with some topping 2MB/s, in random patterns, > sequential is about 150MB/s+. Sequential is not the problem when using SD > cards or most USB drives, random writes is, when you're trying to have an OS > on it. > The best drives around, from Intel, can do 20+MB/s in random writes. > > Most SSDs on the market are based on J-Micron controllers that can do, > at most, 0.04MB/s in random writes. This causes the system to frequently > stall when some app is performing heavy writes to arbitrary locations. > Random reads are mostly very fast with every type of flash you can get. > > http://www.anandtech.com/storage/showdoc.aspx?i=3531&p=25 > > 0.5MB/s in RR should be enough to avoid most stalls. > > I hope that Mich Bradley will educate us but it seems to me that the > hidden eraseblock handling can be the problem with those devices (and if it > is true then compression will not help it either). It seems to be that some > tests are required with physical hardware, a paper processor will not be > enough... :) > True, I just thought it was a good idea to point this out before any decisions are made, especially when most Flash vendors completely disregard random write performance. Best regards > > > Are there any plans using UBIFS? > >
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