Lecture 2

Question 1

What are the 4 stages in the Fetch-execute cycle?

Answer 1

Fetch
decode
execute
store

Question 2

Describe the fetch execute cycle:

Answer 2

1. Fetch (Read): The next instruction is fetched from the memory.
2. Decode: The decoder interprets the instruction and gets decoded.
3. Execute: The CPU passes the decoded information to perform the actions required by the ALU to perform mathematical or logic functions on them.
4. Store: The results stored in the main memory, or sent to an output device.

Question 3

what does virtualization allow?

Answer 3

Virtualization technology enables a single PC or server to simultaneously run multiple operating systems or multiple sessions of a single OS

Question 4

what is a hypervisor?

Answer 4

The solution that enables virtualization is a virtual machine monitor (VMM), or hypervisor

Question 5

What are the 3 requirements for hypervisors?

Answer 5

1. Safety: full control ofvirtualized resources.
2. Fidelity: Behavior of a program on a virtual
   machine should be identical to same program
   running on bare hardware.
3. Efficiency: The code in virtual machine should
   run without intervention by hypervisor

Question 6

What are 2 key reasons for using virtualization?

Answer 6

Rapid deployment-A new VM may be deployed in a
matter of minutes

Ease of management- Virtual machines facilitate deployment and testing of software

Question 7

Define a virtual machine

Answer 7

A Virtual Machine is a software construct that mimics the characteristics of a physical machine

Question 8

What are 2 principle functions performed by a hypervisor?

Answer 8

Execution management of VMs

Devices emulation and access control

Question 9

What is a type 1 hypervisor?

Answer 9

Type 1 hypervisors always run on the bare metal

Question 10

What is a type 2 hypervisor?

Answer 10

 Type 2 hypervisors use the services of an existing host Operating System

Question 11

What are 3 characteristics of Clouds?

Answer 11

1. On-demand self-service
2. Broad network access
3. Resource pooling

Question 12

What are some major challenges in Bringing Virtualization to the x86 architecture

Answer 12

1. The x86 architecture was not suitable for virtualization.

2. The x86 architecture was of daunting complexity

Question 13

What are some benefits of ESX type-1 server architecture?

Answer 13

1. CPU scheduler ensures that each virtual machine gets a fair share of the CPU
2. Memory manager is optimized for scalability

Question 14

What are the 4 virtualization techniques?

Answer 14

CPU Virtualization
 Memory Virtualization
 Storage Virtualization
 Network Virtualization

Question 15

What is paravirulization?

Answer 15

A Software-Assisted virtualization technique that
uses specialized APIs to link virtual machines with the
hypervisor to optimize their performance.
• The operating system in the virtual machine, Linux or
Microsoft Windows, has specialized para-virtualization
support as part of the kernel, as well as specific paravirtualization drivers.
• Allow the OS and hypervisor to work together more
efficiently without the overhead of the hypervisor
translations.

Question 16

What are the 3 ways for VM Optimization?

Answer 16

Para-virtualization
 Hardware-assisted Virtualization
 Containerization

Question 17

What is hardware assisted- virtualization?

Answer 17

Processor manufacturers AMD and Intel added functionality to
their processors to enhance performance with hypervisors
• AMD-V and Intel’s VT-x designate the hardware assisted
virtualization extensions that the hypervisors can take advantage
of during processing
• Intel processors offer an extra instruction set called Virtual
Machine Extensions (VMX)

Question 18

What is containerization?

Answer 18

In this approach, software, known as a virtualization container, runs on top of the host OS kernel and provides an isolated execution environment for applications

Unlike hypervisor-based VMs, containers do not aim to emulate physical servers; instead, all containerized applications on a host share a common OS kernel