On Wed, Aug 02, 2006 at 07:20:25PM -0700, Wil Reichert wrote: > On 8/2/06, Krzysztof Halasa <[EMAIL PROTECTED]> wrote: > >Kyle Moffett <[EMAIL PROTECTED]> writes: > > > >> IMHO the best alternative for a situation like that is a storage > >> controller with a battery-backed cache and a hunk of flash NVRAM for > >> when the power shuts off (just in case you run out of battery), as > >> well as a separate 1GB battery-backed PCI ramdisk for an external > >> journal device (likewise equipped with flash NVRAM). It doesn't take > >> much power at all to write a gig of stuff to a small flash chip > >> (Think about your digital camera which runs off a couple AA's), so > >> with a fair-sized on-board battery pack you could easily transfer its > >> data to NVRAM and still have power left to back up data in RAM for 12 > >> hours or so. That way bootup is fast (no reading 1GB of data from > >> NVRAM) but there's no risk of data loss. > > > >Not sure - reading flash is fast, but writing is quite slow. > >A digital camera can consume a set of 2 or 4 2500 mAh AA cells > >for a fraction of 1 GB (of course, only a part of power goes > >to flash). > > Seeks are fast, throughput is terrible, power is minimal: > > http://techreport.com/reviews/2006q3/supertalent-flashide/index.x?pg=1 > That particular flash drive had terrible througput.
But there are other alternatives. I use a kingston 4GB compactflash card as a disk, and it reads 22MB/s, according to specs and tests with hdparm. And it writes 16MB/s. Much better than the sorry thing in that test, about the same read speed as their worst platter-based harddisk. And of course it still have the nice seek times of non-rotating media. :-) Helge Hafting
