A+ Virtualization and Cloud Computing: What Core 1 Tests

The smallest Core 1 domain, two objectives

Virtualization and Cloud Computing is 11% of Core 1, the smallest of the five domains. It has only two objectives, 4.1 and 4.2, and both are "explain" or "summarize" objectives rather than "given a scenario." In practice, questions still arrive as short help desk situations: a developer needs a disposable test machine, a department's cloud bill doubled, a user's synced files disagree on two laptops. The job is to name the concept that fits.

Type 1 vs Type 2 hypervisors

NIST SP 800-125 describes the two forms of full virtualization. In bare metal (native) virtualization, "the hypervisor runs directly on the underlying hardware, without a host OS." In hosted virtualization, "the hypervisor runs on top of the host OS." A+ calls these Type 1 and Type 2.

Decisions to practice. A company consolidating ten physical servers onto two hosts wants Type 1. A help desk tech who needs to test a Linux distribution on a Windows laptop for an afternoon wants Type 2. A trainer running a classroom lab on each student's existing PC wants Type 2.

One detail that trips people up: Hyper-V on Windows. Microsoft says "Hyper-V features a Type 1 hypervisor-based architecture," even when you enable it as a feature on a Windows desktop, because the hypervisor runs underneath Windows. Microsoft also says Hyper-V can't be installed on Windows 10 Home or Windows 11 Home, and that it needs a 64-bit processor with Second Level Address Translation and at least 4 GB of memory.

What a VM needs

Objective 4.1 lists three requirement areas: security, network, and storage.

• Security. A guest is a full operating system that needs its own updates, antivirus, and accounts. Isolation from the host and other guests is the point of a sandbox, so do not undo it with careless shared folders.
• Network. A VM's virtual network adapter can share the host's connection, sit on the same LAN as a separate device, or stay on an internal-only network. The right choice depends on whether the guest should be reachable.
• Storage. A virtual disk is a file on the host. Ten VMs with 64 GB disks can quietly fill a laptop.

The firmware has to cooperate too. Core 1 objective 3.5 lists virtualization support among BIOS/UEFI settings. Microsoft's Windows 11 requirements note that VM hosts running Hyper-V need virtualization (VT-x, VT-d) enabled in the BIOS, and that a Windows 11 guest needs a generation 2 VM with Secure Boot and a virtual TPM.

The purposes 4.1 lists are worth one sentence each. A sandbox lets you open a suspicious file where damage stays contained. Test development gives developers machines they can reset. Application virtualization keeps legacy software running on an old OS, or runs software built for a different platform.

Containers and VDI

Containers appear in 4.1 next to hypervisors, and the difference is the kernel. Microsoft's comparison puts it this way: a container builds on "the host operating system's kernel," while a VM runs "a complete operating system–including its own kernel." Containers are lighter and start faster. VMs give a stronger security boundary and can run a different operating system from the host.

Virtual Desktop Infrastructure (VDI) hosts desktops on central servers and streams them to users. When a VDI user says "my computer is slow," the problem may be the server or the network, not the thin client on the desk.

Cloud models: who owns it and who uses it

These definitions follow NIST SP 800-145, which A+ terminology tracks closely.

IaaS, PaaS, SaaS: who manages what

NIST's wording is the tiebreaker. In IaaS, the consumer "has control over operating systems, storage, and deployed applications." In PaaS, the consumer controls "the deployed applications and possibly configuration settings for the application-hosting environment." In SaaS, the consumer manages nothing underneath, "with the possible exception of limited user-specific application configuration settings."

Quick checks. A hosted email and office suite where you only add users is SaaS. A provider that runs your web code without giving you an operating system is PaaS. A rented virtual server where you install and patch the OS is IaaS. If the question says you are responsible for patching the operating system, it is IaaS.

Cloud characteristics as help desk scenarios

Cloud and virtualization ideas come back in networking questions, since a VM or a cloud service still needs addressing and name resolution. The networking guide covers that. To see where this domain sits among the other four, use the Core 1 vs Core 2 comparison.

Try the IaaS, PaaS, and SaaS checks above without the table, then practice A+ virtualization and cloud questions with Passy →.