Date   : Fri, 17 Dec 2010 20:17:54 +1100
From   : awilliams@... (Alan Williams)
Subject: Harddisc fakery using a microcontroller

>I seem to recall the PAL on the backplane has something vital to do
with interrupt handling.

Yes I think that it enables RISC iX to identify the podule causing the
interrupt without having to poll them all as RISC OS does.

Alan