Chapter 2

Question 1

What are the classes of interrupts?

Answer 1

1. program = instruction execution (division of 0)
2. timer = timer within processor to perform certain functions
3. I/O = signal of completion, request service from processor, signal of an error condition

Question 2

What are the approaches of interrupts

Answer 2

1. disabled interrupt - ignores interrupts
2. define priorities - higher interrupt priority can interrupt lower priority

Question 3

What are the types of bus interconnection

Answer 3

1. Data bus - provides pathway for data transfer among different components
   - width of bus system determines system performance
2. Address bus - identify source & destination of the data
   - addresses 01111111 - location of memory
   - address 10000000 - IO modules
3. Control bus - prevents data transfer corruptions by managing the control, timing & coordination of buses
   - control signals = transmit command & timing signal
   - timing signal = validate data & address
   - command signals = specify operations to be performed

Question 4

pros & cons of bus interconnection

Answer 4

pros - versatile and low cost

cons - communication bottleneck
- bus length limitation

Question 5

explain Quick Path Interconnection

Answer 5

• connection between processor and io modules
• using 5 layer architecture
  1. physical - wires, cables etc 20 bits phit
  2. data link - flow & error control of sending & receiving 80 bit flits
  3. routing - send 72 bit (8 bit header & 64 bit payload) unit to destination
  4. transport - receive and send data from qpi network that may not be directly connected
  5. protocol = sends & receive messages of packets from memory cache

Question 6

What are the types of qpi

Answer 6

1. multiple direction - direct pairwise connection
   - eliminate arbitrary in shared transmission
2. layered protocol - using layered protocol than control signals in shared bus arrangement
3. packetized data - data sent as packet sequence with control header & control codes