Virtualization and Virtual Machines Lecture Notes

Vocabulary flashcards covering core definitions, hypervisor types, taxonomy, virtualization features, implementation levels, full vs para-virtualization, and resource virtualization.

Virtual Machine (VM)

A software-based computer that behaves like a real computer, equipped with virtual CPU, memory, storage, network, operating system, and applications.

Hypervisor

Special software running on hardware or a host operating system that creates and manages virtual machines by allocating virtual CPU, memory, storage, and network resources.

Guest Operating System

The operating system installed inside a virtual machine (such as Ubuntu, Windows, or Linux) that manages applications within that specific VM.

Host Operating System

The main operating system installed directly on the physical computer hardware that controls hardware components and manages system resources.

System Virtual Machine

A type of virtual machine that creates a complete virtual computer and runs a full operating system (e.g., VMware, VirtualBox, AWS EC2).

Process Virtual Machine

A virtual environment designed to run a single application or program, lasting only as long as the execution of that program (e.g., Java Virtual Machine, .NET CLR).

Type 1 Hypervisor

A hypervisor installed directly on physical hardware without requiring a host OS, offering high performance, better security, and efficient resource utilization for enterprise environments.

Type 2 Hypervisor

A hosted hypervisor installed on top of an existing host operating system, communicating with hardware through the host OS (e.g., Oracle VirtualBox, VMware Workstation).

Virtualization

The technology or process of creating a virtual (software-based) version of physical resources like servers, operating systems, storage devices, or networks on a single physical machine.

Scalability (Virtualization)

A feature of virtualization that allows administrators to easily add or remove virtual machines based on changing workload demands.

Isolation (Virtualization)

A security feature ensuring each virtual machine operates independently, so that crashes, errors, or viruses in one VM do not affect others.

Load Balancing

The practice of sharing work evenly across multiple virtual machines to optimize processing efficiency and system performance.

Resource Pooling

The practice of efficiently sharing physical CPU, memory, storage, and network resources among multiple virtual machines.

Hardware Independence

A virtualization capability allowing virtual machines to be moved between different physical servers without encountering compatibility issues.

Virtualization Structure

The layered architecture consisting of physical Hardware, Host Operating System, Hypervisor, Guest Operating System, Libraries, and Application Processes.

Instruction Set Architecture (ISA) Level Virtualization

Virtualization implemented at the processor instruction level that translates instructions from one CPU architecture to another, enabling cross-architecture emulation.

Hardware-Level Virtualization

Virtualization implemented directly on physical hardware using a hypervisor to partition resources into independent virtual machines running distinct OSs.

Operating System-Level Virtualization

A virtualization technique that creates multiple isolated user space environments (containers) that all share the same operating system kernel.

Library Support-Level Virtualization

Virtualization where compatibility libraries intercept application system calls and translate them into commands understood by the host operating system.

Application-Level Virtualization

Virtualization where applications are packaged with all necessary files to run in an isolated virtual environment without full installation on the host system.

Full Virtualization

A virtualization technique where the hypervisor provides complete hardware emulation so unmodified guest operating systems can run unaware that they are virtualized.

Para-Virtualization

A virtualization technique where the guest operating system is modified and aware of virtualization, using direct hypercalls to communicate with the hypervisor.

Hypercall

A specialized instruction call used by a modified guest operating system in para-virtualization to request services directly from the hypervisor.

CPU Virtualization

The process of dividing a physical CPU into multiple virtual CPUs (vCPUs) and scheduling execution time among virtual machines.

Input/Output (I/O) Virtualization

The technique allowing multiple virtual machines to share physical input/output hardware (such as disks, network cards, and USB devices) through virtual I/O devices created by the hypervisor.