On Mon, Dec 17, 2007 at 11:28:51PM +0100, Pontus wrote: > Stuart Henderson wrote: > > On 2007/12/17 15:51, Pontus Pihlgren wrote: > > > >> Also, how important is speed? I think a read speed of 20 MB/s is quite > >> sufficient, no? > >> > > > > I don't think you'll get close to 20MB/s. > > > > For OpenBSD you'll get the best speeds from a card which supports > > multi-sector IO (6MB/s or so?). The Sandisk cards I've seen do, > > many others are 1-sector only and a lot slower on OpenBSD (2MB/s > > or so; looks like DMA is disabled in those cases - I'm not sure > > whether that's necessary, and doesn't apply to all OS, but it's > > the way it is at the moment). > > > Oh, that sounds a bit discouraging. Isn't CF just a variant of the IDE > bus, and should therefore be able to reach speeds of 33 - 133 MB/s > depending on the controller. I realize that a caveat in the OpenBSD > driver could slow things down, but all the way to 2MB/s ? I'm not saying > you are wrong, I'm just surprised. Have you done some benchmarks?
FWIW, on a 5501 with DMA enabled and on Linux, using a SanDisk SDCFX3-2048 (and indeed multi-sector): # dd if=/dev/hda1 of=/dev/null bs=128k iflag=direct 377+1 records in 377+1 records out 49512960 bytes (50 MB) copied, 6.80798 seconds, 7.3 MB/s Even with DMA, speed is not very high (but the system load is low). regards, iustin _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
