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  1. LPU MCA Semester 1
  2. CAP470
  3. Unit 3

CAP470 · Unit 3: Cloud virtualization

Virtual machines and their properties

10 practice questions · in the MTE and ETE syllabus

Practise this topicPractise this topic

Key points

  • A VM runs a full guest OS on virtual hardware
  • Encapsulation allows snapshots and migration
  • Isolation separates VMs on one host
  • Limits stop one VM starving the others

A virtual machine (VM) is a software computer with virtual CPU, memory, disk and network that runs its own guest operating system on a hypervisor.

Key properties:

  • Isolation: one VM cannot read or crash another.
  • Encapsulation: the whole VM is stored as files, enabling copy, snapshot and backup.
  • Hardware independence: the guest sees standard virtual hardware, so it can run on different hosts.
  • Partitioning: host resources are divided among VMs, with limits and reservations to prevent one VM from starving others.
  • Live migration: a running VM moves between hosts with little or no downtime.

Because every VM carries a full guest OS, it is heavier and slower to start than a container but provides stronger isolation and lets different operating systems share one host.

Example: one laptop can run a Windows VM and a Linux VM for testing.

Exam trap: a VM has its own kernel, whereas a container shares the host kernel.

Try two questions

Question 1 · Tier 3, Apply

A VM running on one host is moved to another host without stopping it. What is this called?

  1. Cold boot
  2. Disk defragmentation
  3. Static partitioning
  4. Live migration
Show the answer

D. Live migration moves a running VM between hosts with little or no downtime.

Why not A: A cold boot is starting a machine from powered-off state.

Why not B: Defragmentation reorganises disk blocks.

Why not C: Static partitioning fixes resource allocation in advance.

Question 2 · Tier 2, Understand

Which VM property means one VM cannot read or crash another VM on the same host?

  1. Isolation
  2. Portability
  3. Encapsulation
  4. Compatibility
Show the answer

A. Isolation keeps each VM separate so faults and attacks do not spread easily.

Why not B: Portability is about moving VMs between hosts.

Why not C: Encapsulation means a VM is stored as a set of files.

Why not D: Compatibility is about running standard software.