Hello. Recently my FreeBSD keep complaining DMA ICRC error on r/w hdd
(os hangs sometimes). I tried to hang my hdd to both primary/secondary
ide controller in either slave or master mode, and the problem keeps
still. I later turned off dma in the OS thus I no longer get complains.

If you have another hard drive you can use, try windows on that machine and
see if the same thing occurs.
I would suspect the drive itself is the problem and not the controller
though.. although if it runs fine in PIO mode (non-dma), then it could be
something as simple as the cable is worn (and having problems at udma
speeds)..

Are you using standard 40 wire IDE cables, or 80 wire ATA cables (will
usually be blue/red on one end) ?

A google search for "freebsd"+"UDMA ICRC error" reveals a number of posts to
various freebsd forums.

My question: is IDE extend card related to OS? Do I have to buy an
'freebsd complaint' card, or it is not related to OS and any such device
will work?

Check the supported hardware list on freebsd.org for the version you're
running (e.g. 4.x, 5.x, etc).. freebsd it pretty good with support for just
about anything so you shouldn't have too many troubles..


Regards,
Chris