On Wed, Jun 27, 2007 at 12:42:18PM -0700, Radu-Cristian FOTESCU wrote:
> 
> ... but I am curious: how are you determining that a Linux box is frozen?

First, the clock on the gnome panel freezes.  After a minute of that,
no response to ctrl-alt-backspace.   Then, no response to ping from
another machine.  Finally, in this case, no response to the reset
switch; THAT is a lockup indeed!  It took a power interruption to
bring the machine back. 

I'm guessing the problem is due to the Adaptec 2940 SCSI card
doing something really nasty to the bus, perhaps trying to DMA an
infinite-length record.  Given the enormous data files that a 
a scanner can potentially produce, an driver that does not do
proper bounds checking, or does not recover from bus errors (the
cable approaches the length limit) might freeze the bus this way.
It is interesting that an obsolete user configuration can bring
this about.  This is all rank speculation, of course.


Keith

-- 
Keith Lofstrom          [log in to unmask]         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs