CH18

Question 1

describe what is meant by RISC and CISC processors (4)

Answer 1

RISC; it uses simple instructions with fixed length instructions and makes use of pipelining

CISC; has a large instruction set and requires complex circuits

Question 2

2 differences between RISC and CISC processors (2)

Answer 2

1. RISC has fewer instructions, CISC has many instructions
2. RISC uses many registers, CISC uses fewer registers

Question 3

describe 2 benefits and one limitation of using a virtual machine to emulate a new computer system (3)

Answer 3

benefit 1: new system can be tried on different virtual hardware without need to purchase the hardware

benefit 2: easy to recover if software emulating the new computer system causes crash as VM provides protection to other software

limitation: a virtual machine might not be as efficient because the processing time is increased

Question 4

describe SIMD

Answer 4

many processors execute the same instruction using different data sets

Question 5

describe MISD

Answer 5

many processors using different instructions use the same data set

Question 6

describe MIMD

Answer 6

many process use many instructions using different data sets

Question 7

describe the process of pipelining during the fetch-execute cycle in RISC processors (4)

Answer 7

1. instructions are divided into sub tasks
2. each subtask is completed during one clock cycle
3. no 2 instructions can execute their same at the same clock cycle
4. the 5 stages: IF, ID, OF, IE, WB

Question 8

what is meant by a virtual machine

Answer 8

the emulation of computer system using a host computer system

Question 9

state 2 benefits of a virtual machine

Answer 9

1. different VMs can be used on the same computer
2. cost savings due to not needing to purchase extra hardware

Question 10

state 2 drawbacks of a virtual machine

Answer 10

1. cannot emulate some hardware
2. complex to maintain

Question 11

outline the characteristics of massively parallel computers (3)

Answer 11

a large number of separate computers are connected together creating a network infrastructure and communicating by sending messages

Question 12

describe the use of pipelining in RISC (2)

Answer 12

1. allows several instructions to be processed simultaneously, therefore increasing the number of instructions completed per unit time

Question 13

describe features of SISD

Answer 13

single instruction, single data architecture. Executes instructions sequentially

Question 14

describe the features of MIMD

Answer 14

multiple instructions, multiple data architecture and operates independently