[Info-vax] DZQ11 on VAX/4000 Model 300

[Scott Dorsey]

David Wade  <g4ugm at dave.invalid> wrote:
>
>Why does it hang when the card is removed? Thats not expected to me...
>.. if the CSRs worked before, surely they work the same afterwards....

There are interrupts which are laddered board-to-board rather than run
down the backplane.  If there is an empty space in the backplane, the 
cards after the empty space cannot see those interrupts.  Therefore, we
either move all the other cards up or we put a bus grant card into the
empty place.

This allows prioritization, and it is why you put the higher speed 
controllers closer to the CPU in the backplane than you do the slower
devices.
--scott
-- 
"C'est un Nagra. C'est suisse, et tres, tres precis."