Allen Briggs wrote:
>On Wed, Jan 21, 2004 at 09:58:36PM -0700, Joel Rees wrote:
>>  I recall the 68k provided for peripherals putting a code that could be 
>>  used for a device code (so to speak) on the bus during the interrupt 
>>  response cycles. Did the nubus spec prevent using that, or was it just
>  > Apple's corner-cutting?
>
>I don't recall this, but the 68k does allow different interrupt levels.
>The nubus interrupts are all wired together, though, into one interrupt
>input on a VIA (or VIA-replacement) on the Mac.
>

There is no obvious reason why one NuBus slot should be more 
important than another, so they are wired together.
The software can control their relative importance by the order in 
which they are interrogated.
It's not "corner-cutting" so much as retaining flexibility.

Dan Killoran