I'm not an expert on your SCSI issues, so I'll just go ahead and answer
your X problem.

> Finally, some X problems. Before that nasty disk crash I was running
> X.11Mar95 + Xmacbsd-961027. After I run xinit I got console message
> about video, correct screen size and some addresses. ( I do not
> remember and can not repet it). After that the upper part screen was
> divided into 8 colored squares with smaller white rectangles in
> them. It seems that X has created 8 identical small displays. The
> mouse movement and text were identical in all windows and I can even
> run X clients (but I can not read the text!). xdm worked the same: 8
> identical login screens. Did I forget some options or some config
> files?

No, you didn't.  You just forgot to read the documents carefully.  The
Xmacbsd server currently does not support color displays in any color
depths but 1-bit (which isn't really a color display).  You need to
set your color depth to 1-bit before booting NetBSD.

ken