Ultra ATA card doesn't seem to provide Ultra speeds.

[Buckie]

Soeren,

Heh, QNX in first RTP incarnations only had /dev/zero and I sort of
get used to it.
But nevermind. I've already tried large bsizes (1m and more) and
/dev/null too. But I can't really get past the 16Mb/s barrier...
Does machine speed really should affect the hard drive performance so
much? I don't think that top showed me the processor usage on dd more
than 30%, then again it might be something else...
I also had a thought about measuring raw io performance, but the only
way I know is dd to zero (null). I'm saying this because in... ugh...
Windows I get raw io speeds of up to 60(!) Mb per second (HDTach). And
that's fine but Windows doesn't want to mount any volumes off this
drive if the speed is set to something more than WDMA2 (even UDMA0).
It can only access it sector-by-sector, but without any problems
though.
Overall, the SI0680 card is a mystery! And SiliconImage is silent as
well.
Any other ideas as to how to measure the performance or ways to speed
it up somehow or test it?

Z

SS> OH, you need to output to /dev/null NOT /dev/zero :)

SS> besides that, all looks OK, but you need a fairly large bs to se improvments
SS> on this (relatively slow) machine, try a bs of 1m and see if that
SS> helps, if not there is something slowing down your system..


SS> -Søren
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-- 
Best regards,
 Buckie                            mailto:freebsd1 at centrum.cz