Fundamentals of Computer Systems – Chapter 8: Virtualization & Isolation

Question-and-answer flashcards covering key terms, architectures, benefits, and technologies of virtualization and isolation as presented in Chapter 8.

What is the basic definition of virtualization?

An abstraction layer that decouples physical hardware from the operating system or service request.

Which three business challenges drive today’s interest in virtualization for CIOs?

Cost-effective IT utilization, responsiveness to new initiatives, and flexibility for organizational change.

Give an everyday example of virtualization in operating systems.

Virtual memory, which lets software use more memory than is physically available by swapping pages to disk.

What is a virtual machine (VM)?

Software that emulates a computer environment, allowing an OS and applications to run independently of the physical hardware.

Name the two main x86 virtualization approaches.

Hosted architecture and bare-metal (hypervisor) architecture.

In the hosted approach, where does the virtualization layer run?

On top of a conventional host operating system as an application.

In bare-metal virtualization, what sits directly on the hardware?

A hypervisor/virtualization-centric kernel with direct access to hardware resources.

What is a hypervisor?

Software that creates and manages virtual machines by abstracting and allocating hardware resources.

List three core benefits of virtualization for enterprises.

Server consolidation, improved business continuity, and rapid test/development provisioning.

How much can server utilization rise when using virtualization versus traditional deployments?

From roughly 5–15 % to about 60–80 %.

Which virtualization product popularized x86 virtualization in 1998?

VMware.

Define partitioning in virtualization.

Running multiple operating systems on a single physical machine while sharing its hardware.

Why is isolation important in virtualization?

It prevents workloads from affecting each other, enhancing security, stability, and troubleshooting.

Give four dimensions of VM isolation.

Resource, memory, file-system, and network isolation.

What does VM encapsulation mean?

An entire VM, including OS, apps, and state, is stored as a set of files that can be moved, cloned, or snapshotted.

What key property makes VMs hardware-independent?

Standard virtual hardware exposed by the hypervisor hides the underlying physical hardware.

What is para-virtualization?

A technique where the guest OS is modified to cooperate with the hypervisor for higher performance.

Which drawback accompanies para-virtualization?

Modified OSs cannot run directly on non-virtualized (bare) hardware.

Name three technologies that help achieve VM isolation.

Hypervisors (e.g., ESXi), virtualization platforms (e.g., VirtualBox), and container systems (e.g., Docker).

What are the three traditional properties of an efficient Virtual Machine Monitor (VMM)?

Fidelity, Isolation (Safety), and Performance.

Explain ‘server sprawl’ and how virtualization addresses it.

Server sprawl is the proliferation of under-utilized physical servers; virtualization consolidates them into fewer, well-utilized hosts.

What management features are essential for a true virtual infrastructure (beyond basic partitioning)?

Resource monitoring, automated provisioning, high availability, and live workload migration.

What VMware feature enables live migration of a running VM between hosts?

VMotion.

How does virtualization improve business continuity?

By encapsulating entire systems as files that can be replicated and restored quickly on any host.

List two cost areas dramatically reduced by virtualization-based server consolidation.

Power & cooling costs and physical rack/floor space.

What is the usual life-cycle advantage of a VM over a physical server?

VMs are easier to copy, move, back up, and restore, thus extending usability and reducing downtime.

Which historical hardware trend (famous ‘law’) fueled datacenter growth and virtualization needs?

Moore’s Law—doubling of transistor counts and processing power roughly every 18 months.

Why did early Windows deployments often follow a ‘one server, one application’ rule?

OS limitations and application conflicts made multi-app installations unstable, leading to low utilization.

What is a consolidation ratio in virtualization?

The number of VMs that run on a single physical host.

How does virtualization enable rapid test & development environments?

By reusing and cloning pre-configured VM templates, reducing provisioning time from days to minutes.

State one main difference between VMs and containers regarding isolation.

VMs include their own OS kernel, providing stronger isolation; containers share the host OS kernel.

What is VMware ESX/ESXi classified as?

A bare-metal (Type-1) hypervisor.

Which VMware tool provides a GUI for managing VMs and hosts?

vSphere Client (or vCenter when centralized management is needed).

What is VMware ACE designed for?

Secured enterprise desktop virtualization with policy controls.

Give two common modern use-cases for virtualization besides server consolidation.

Running legacy applications on modern hardware and dynamic disaster-recovery replication.

Explain ‘performance isolation’ in VM environments.

Partitioning and allocating resources so one VM’s workload does not degrade another’s performance.

What are VM snapshots used for?

Capturing a VM’s complete state at a point in time for backup, testing, or rollback.

How can virtualization reduce provisioning time for new services?

New VMs can be deployed from templates without waiting for physical hardware procurement.

Name one reason virtual machines enhance portability.

Their encapsulated files can be moved to any compatible host regardless of hardware vendor.

What is meant by ‘Create once, run anywhere’ in VM compatibility?

A VM built on one host runs unmodified on any other host that offers the same virtual hardware standard.

Which layer in the virtualized stack transforms separate servers, storage, and networking into a pooled resource?

Virtual infrastructure layer managed by tools like VMware VirtualCenter.

Highlight one security advantage of desktop virtualization.

Centralized policy enforcement while allowing end-user autonomy; malware in one VM cannot infect others.

Why do hypervisors provide a higher consolidation ratio than application-level partitioning?

They virtualize the full hardware stack, allowing heterogeneous OSs and stronger isolation.

What is ‘virtualization-first policy’?

An IT strategy where new workloads are deployed as virtual machines by default.

Name two popular Type-2 (hosted) hypervisors.

VMware Workstation and Oracle VirtualBox.

How did virtual memory inspire broader virtualization concepts?

It abstracted physical RAM, showing that resources can be pooled and oversubscribed safely, a model later applied to CPUs, storage, and networks.

Summarize the ultimate goal of datacenter virtualization as stated in the course conclusion.

Optimize resource usage, lower costs, and create a scalable platform foundational for cloud computing.