Advanced Operating Systems - Virtualization and Computing Environments

Vocabulary practice flashcards covering virtualization concepts, hypervisor implementations, cloud computing service models, and operating system architectures based on Operating System Concepts (9th Edition).

Virtualization

The abstraction of the physical hardware of a single computer into several distinct execution environments, allowing operating systems or applications to run on created virtual machines.

Host

The underlying physical hardware system that provides the computational resources for virtualization.

Virtual Machine Manager (VMM)

Software or firmware (also known as a hypervisor) that creates and manages virtual machines by presenting an execution interface that is identical to the underlying host hardware.

Guest

A process—typically an operating system—running inside a virtual machine that is provided with a virtual copy of the host hardware.

Nonvirtual Machine Architecture

A standard computing model where user processes run above a single operating system kernel that directly manages the underlying physical hardware across a programming interface.

Virtual Machine Architecture

A system architecture where a Virtual Machine Manager (VMM) abstracts the physical hardware into separate virtual machines ($\text{VM1}$, $\text{VM2}$, $\text{VM3}$), allowing each guest kernel and its processes to run concurrently on the same hardware.

Type 0 Hypervisor

A hardware-based virtualization solution that provides support for virtual machine creation and management directly via firmware (e.g., IBM LPARs and Oracle LDOMs).

Type 1 Hypervisor

Operating-system-like software designed specifically to deliver virtualization (e.g., VMware ESX, Joyent SmartOS, Citrix XenServer), or a general-purpose operating system that provides standard OS services alongside hypervisor functions (e.g., Microsoft Windows Server with Hyper-V, RedHat Linux with KVM).

Type 2 Hypervisor

An application running on top of a standard host operating system that supplies virtualization and VMM features to guest operating systems (e.g., VMware Workstation, VMware Fusion, Parallels Desktop, Oracle VirtualBox).

Paravirtualization

A virtualization technique where the guest operating system is explicitly modified to coordinate directly with the VMM to achieve optimized performance.

Programming-Environment Virtualization

A virtualization model where the runtime does not virtualize real hardware, but instead provides an optimized virtual execution system for applications (e.g., Oracle Java, Microsoft .NET).

Emulator

A software or hardware layer that translates instructions to allow applications compiled for one hardware environment to run on an entirely different architecture, such as running PowerPC programs on Intel x86 CPUs.

Application Containment

A mechanism that isolates applications from the host operating system without true hardware virtualization, improving security and manageability (e.g., Oracle Solaris Zones, BSD Jails, IBM AIX WPARs).

Snapshot

A saved image of a virtual machine's complete state at a specific point in time, allowing the VM to be reverted to that exact configuration later.

Templating

The creation of a standardized, pre-configured virtual machine image (operating system plus applications) used to deploy multiple identical guest instances.

Live Migration

The operation of moving an actively executing virtual machine from one physical host to another without interrupting user access or running services.

Virtual CPU (VCPU)

A data structure implemented by a VMM to maintain the expected CPU register and execution state for each individual guest operating system.

Trap-and-Emulate

A virtualization approach on dual-mode CPUs where the guest OS runs in user mode, causing privileged instructions to trap to the VMM, which emulates the action in a virtual kernel mode.

Public Cloud

A cloud computing infrastructure made publicly available across the Internet to any individual or organization willing to pay for usage.

Private Cloud

A cloud deployment implemented and operated solely for the private use of a single organization.

Hybrid Cloud

A computing configuration that integrates both public cloud and private cloud infrastructure components.

Software as a Service (SaaS)

A cloud delivery model providing complete end-user applications (such as a word processor) directly accessible via the Internet.

Platform as a Service (PaaS)

A cloud service model providing a configured software stack (such as a database management system) prepared for application development and deployment over the network.

Infrastructure as a Service (IaaS)

A cloud computing tier providing foundational computing resources—such as virtual servers or network-attached backup storage—delivered over the Internet.

Real-Time Operating System (RTOS)

An operating system designed for embedded environments with strict, fixed time constraints, where correctness depends entirely on finishing execution within specified deadlines.

Copyleft

A licensing concept pioneered by the Free Software Foundation (FSF) via the GNU General Public License (GPL) ensuring that released source code and its derivatives remain freely accessible.