CSI CHAP 15: HARDWARE AND VIRTUAL MACHINES

What are the differences between RISC and CISC? (8)

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How does interrupt handling work on RISC and CISC processors?

1. As soon as the interrupt is detected, the current processes are paused and moved into registers

2. the ISR is loaded onto the pipeline and is executed

3. When the interrupt has been serviced, the paused processes are resumed by bringing them back from the registers to the pipeline

What is the use of pipelining?

• allows several instructions to be processed simultaneously

• thus, increasing the number of instructions completed per unit time

describe the process of pipelining during the F-E cycle in RISC processors. (4)

1. instructions are divided into ___ stages: (name them)

2. …

3. …

4. …

1. instructions are divided into 5 stages:

   • Instruction Fetch (IF)

   • Instruction Decode (ID)

   • Operand Fetch (OF)

   • Instruction Execute (IE)

   • Write Back Result (WBR)

     2. Each subtask is completed during one clock cycle

     3. No two instructions can execute their same stage at the same clock cycle

     4. the second instruction begins in the second clock cycle, while the first instruction has moved on to its second subtask

What is the use of the registers in RISC processors?

pipelining requires processors with several registers to store each of the stages

What are the four basic computer architectures?

1. SISD

2. SIMD

3. MISD

4. MIMD

Describe SISD (3)

• single instruction, single data architecture

• contains one processor, a control unit and a memory unit

• that executes instructions sequentially

describe SIMD

• single instruction, multiple data architecture

• the instructions can be performed sequentially, taking advantage of pipelining

• parallel computers with multiple processors

describe MISD (3)

• multiple instruction, single data architecture

• each processor works on the same data stream independently

• parallel computers with multiple processors

describe MIMD (3)

• multiple instruction, multiple data architecture

• contains many processors

• that operate independently

What are the characteristics of massively parallel computers? (4)

A large number of separate computers connected together

simultaneously performing a set of coordinated computations

the computers communicate by sending messages

network infrastructure: forming one machine with several thousand processors

What is a virtual machine?

emulation of a computer system using a host computer system

Give examples of the role of virtual machines (2)

used by companies wishing to use the legacy software on newer hardware and server consolidation companies

virtualizing machines allows developers to test applications on many systems without making expensive hardware purchases

what are the benefits of virtual machines? (3)

• security benefits

• allows more than one operating system to run on a system

• allows multiple copies of the same operating system

what are the limitations of virtual machines? (3)

• affected by any weaknesses of the host machine

• costly

• time and effort needed for implementation is high

What are the benefits of karnaugh maps?

• minimizes the number of boolean expressions

• minimizes the number of logic gates used, thus providing a more efficient circuit

What is the role of flip flops as data storage elements?

• flip flops can store a single bit of data as 1 or 0

• computers use bits to store data

• flip-flops can be used to store bits of data

• memory can be created from flip-flops

What is A (with a horizontal line on top)?

What is A.B?

What is A+B?

NOT A

A AND B

A OR B

Fill the table.

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