"Michael K. Sanders" <msanders@confusion.net> writes:

> I have a 1.3.2 system with an IDE disk that was showing some corrected
> soft errors in my logs, so I wanted to check the disk with dd.  I did
> the following:
> 
>     dd if=/dev/rwd0f of=/dev/null bs=8192k
> 
> and the system promptly panic'ed.  In retrospect, that seems like a
> large block size, but I didn't expect a panic... is this a bug, or
> operator error?

The problem is that pde's are not allocated on demand in 1.3
(sometimes).  This means that if you do raw io to a region that
is bigger than 4Meg, you don't stand a chance.  If you drop the
size to a meg or so, chances are it will work.