Fri, 5 Apr 2013, 01:37

A student writes:
 
> Professor Patt,
> 
> In the lab 4's instructions, there is a term that "you do not need
> to worry about nested interrupts and exceptions for this assignment". 
> Can I get confirmed what that means?
> 
> Thanks sincerely,
> <<name withheld to protect a student wanting more about nested interrupts>> 


Nested interrupts and exceptions are like nest subroutines, for example.
That is, in the service routine dealing with the interrupt or exception,
another interrupt or exception occurs.  Certainly that can happen.  In the 
case of interrupts it happens all the time.  While servicing an interrupt, 
a higher priority interrupt comes along.  While servicing an exception,
perhaps a page fault occurs.  Or, while servicing an exception, a higher
priority interrupt occurs.  All are examples of nesting of interrupts
and exceptions, which are important to deal with.  ...but, to make life
a little easier, not in lab 4!

Good luck finishing lab 4 by Sunday night.

Yale Patt