Architecture & Components

Question 1

define architecture

Answer 1

attributes of a system, direct impact on logical execution

Question 2

define organisation

Answer 2

how the architecture is implemented

Question 3

define structural

Answer 3

the way the components relate to each other - hierachical

Question 4

define function

Answer 4

operation of individual components

Question 5

name the main 5 components of a computer

Answer 5

1. CPU
2. main memory
3. I/O
4. system bus
5. co-processors

Question 6

name the 4 main components of the CPU

Answer 6

1. control unit
2. ALU
3. registers
4. interconnection

Question 7

what does the CPU do

Answer 7

controls operation, FDE cycle

Question 8

what does the control unit do

Answer 8

controls operation of CPU

Question 9

what does main memory do

Answer 9

stores data and program instructions

Question 10

what does I/O allow

Answer 10

allows machines to gain information and interact with the users and other devices

Question 11

what is the cache

Answer 11

smaller, faster, located closer to the CPU, stores frequently used instructions & data

Question 12

3 components of a multicore

Answer 12

1. CPU
2. Core - individual processing unit
3. processor - contains one or more cores

Question 13

what are switches & how are they used in computers

Answer 13

• two states, easy to map logical states
• allows for boolean logic to be performed
• binary arithmetic
• storage of data in binary form

Question 14

what is von nuemann architecture

Answer 14

• data & instructions stored in same single read-memory
• content of this memory are addressable by location

Question 15

name the 7 main registers

Answer 15

1. MAR
2. MDR
3. CIR/IR
4. PC
5. MBR
6. AC & MQ (Multiplier Quotient)
7. IBR

Question 16

what does the MBR do

Answer 16

contains a word to be stored in memory or sent to the I/O unit OR is used to receive a word from memory or form I/O unit

Question 17

what does the IBR do

Answer 17

temporarily hold the right hand instruction from a word memory

Question 18

what is the opcode

Answer 18

code for instruction to perform

Question 19

what is the operand

Answer 19

data to perform instruction or address to use

Question 20

3 instruction types

Answer 20

1. data handling
2. arithmetic & logic
3. control flow

Question 21

describe the FDE cycle

Answer 21

1. Fetch
   - opcode of the next instruction is loaded in to IR
   - address portion is loaded into the MAR
   - data portion is loaded into the MDR
2. Decode
   - decodes instruction
3. Execute
   - interprets opcode as control signals
   - sends out control signals to cause data to be moved or an operation to be performed by ALU

Question 22

describe the von neumann bottleneck

Answer 22

• shares memory bus for data and program instructions
• single bus limits throughput between CPU and memory
• CPU must wait for data to be moved to or from memory

Question 23

mitigations for the von neumann bottleneck

Answer 23

• cache between CPU & main memory
• seperate caches or seperate access paths for data & instructions
• on-chip scratchpad memory to reduce memory access
• implementing the CPU & memory hierarchy as a system on chip - greater locality of reference = v latency

Question 24

define harvard architecture

Answer 24

• difference = 2 buses = memory & data
• ADV: CPU recieves instruction & data concurrently
• DIS: programs cannot be stored in same memory as data
• uses: microcontrollers, digital signal process

Question 25

name the 2 computer building blocks

Answer 25

1. logic gates - implements a single boolean or logical function 2. memory cell - store one bit of data, can be in one of two states at any time

Question 26

define transistors

Answer 26

- fundmanental building blocks of gates & memory cells - semiconductor - conductive or nonconductive - discrete component = self-contained

Question 27

define integrated circuits

Answer 27

- each chip consists of many gates and/or memory cells plus I/O attachment points - used to contain thousands of transistors

Question 28

define moore's law

Answer 28

every 18 months, the amount of transistors on an IC doubles

Question 29

consequences of moore's law

Answer 29

- v cost of computer logic & memory circuitry - ^ operation speed as v eletrical path length - v computer size - v power & cooling requirement

Question 30

what are general purpose registers used for

Answer 30

data & addressing

Question 31

what is a program status word register

Answer 31

stores a set of bits, typically including condition codes like - zero flag - carry - overflow - interrupt enable/disable - interrupt flags

Question 32

what are the HACK computer registers

Answer 32

1. Address (A) - specifies the address in memory of the word to be written from or read two OR can be used as a data register 2. Data (D) - contains a word to be stored in memory or sent to the ALU 3. Program counter - contains the address of the next instruction pair to be fetched from memory

Question 33

FDE cycle in the HACK computer

Answer 33

1. Instruction decoding - determines if the instruction is an A-instruction or C-instruction 2. Instruction execution - instruction fields are routed to various parts of the architercture 3. Fetch Next Instruction - as a result of the previous instruction the CPU outputs the address of the next instruction to execute using the program counter