Virtual machines

Virtual machines are a transformative technology that allows computer programs and applications to be run on existing hardware without the need to duplicate physical systems. They enable remote and cloud computing, allowing organizations to maximize hardware utilization, streamline operations and scale computing environments efficiently, whether on-premises or in the cloud.

Virtual machines adapt to a wide range of computing scenarios, from consolidating workloads to creating secure, isolated environments for testing and development. They support multiple operating systems on a single physical machine, improve resource allocation and reduce infrastructure complexity. Discover how they work and some key use cases for virtual machines with Micron. Find out how Micron’s memory and storage technologies enhance performance for these demanding environments by contacting Micron’s Sales Support team.

What are virtual machines?

Virtual machines definition: Virtual machines (VMs) are software-based emulations of physical computers, running their own operating systems and applications on virtualized hardware resources within a host system.

Each virtual machine behaves like a stand-alone device, complete with its own operating system, applications and virtualized hardware resources, all running on a shared physical system. 

Rather than duplicating physical infrastructure, virtual machines share the underlying hardware of a host system. Each virtual machine operates as an isolated “guest,” with its own allocated central processing unit (CPU), memory and storage. This isolation enhances security and stability, enabling multiple operating systems to run on the same physical machine without interference.

A common example of a virtual machine is a virtual server: software that simulates a physical server and allows multiple users to access applications, documents and systems remotely, without needing a direct connection to the physical server.

Virtual machines deliver significant benefits for organizations. They maximize hardware utilization, streamline operations and reduce costs by enabling more workloads to run on existing hardware. Virtual machines also provide flexibility. Users and teams can adapt their environments, test new software without risk to the primary system and run multiple operating systems on a single machine. Organizations can update their infrastructure by deploying VM software rather than replacing or updating physical computer systems — leveraging the hardware they already have and providing a less complex and cost-effective alternative.

Additionally, the segmentation of access and applications into different areas of a single computer environment allows for enhanced cybersecurity and greater access transparency. Within a virtual machine, usage of each segmented area can be monitored and organizations can assign different levels of access — granting or restricting permissions as needed — to ensure that only authorized users can reach sensitive systems. This layered approach to resource management not only strengthens security but also provides clear visibility into how virtual environments are used, supporting compliance and operational oversight.

How do virtual machines work?

Virtual machines work by relying on a process known as ​​virtualization, which refers to the creation of virtual technologies that can be installed into physical computer hardware.

Imagine a virtual machine as a software-based computer that runs inside a real, physical computer. Instead of needing separate hardware for each operating system or application, virtual machines allow multiple “virtual computers” to share the same physical resources — like memory, storage and processing power — while remaining isolated from one another.

This is made possible through a technology called virtualization, which creates a layer between the physical hardware and the software environments running on it. At the heart of virtualization is the hypervisor, a specialized software or firmware that manages how hardware resources are allocated to each virtual machine. Hypervisors allow multiple virtual machines to coexist on a single server without interfering with one another.

There are two main types of hypervisors:

• Type 1 hypervisors (bare metal): Run directly on the physical hardware and are commonly used in enterprise and data center environments.
• Type 2 hypervisors (hosted): Run on top of an existing operating system and are typically used for desktop virtualization or development environments.

Each virtual machine is referred to as a “guest,” while the physical computer it runs on is the “host.” Guests are isolated from each other and from the host’s operating system, which enhances security and stability. Developers and IT teams can configure how much CPU, memory and storage resources each virtual machine uses, ensuring optimal performance without overloading the host.

Micron’s high-speed dynamic random-access memory (DRAM) and solid-state drives (SSDs) are essential to this process. They provide the fast, reliable access to memory and storage that virtual machines need to run efficiently, especially in environments where multiple virtual machines are operating simultaneously.

What is the history of virtual machines?

Virtual machines have a history dating back to the mid-20th century, with expanded applications across the last few decades.

• 1960s, time-sharing systems and advent of virtual machines: Early virtual machine concepts emerged from time-sharing systems, such as IBM’s CP-40 and CP/CMS, allowing multiple users to share computing resources.
• 1970s, Pascal p-code and growing popularity: In 1973, the introduction of Pascal p-code enabled virtual execution of instructions without dedicated hardware, laying the groundwork for language-based virtual machines. IBM’s VM/370 also brought commercial VM technology to mainframes.
• 1990s, commercialization and modern developments: The 1990s saw significant advances in virtualization technology, including the introduction of managed runtimes like the Java virtual machine (JVM), which enabled platform-independent software execution. Virtual machines became more efficient, with improved alignment between guest and host systems. In 1999, VMware launched the first widely adopted commercial virtualization product for x86 systems, revolutionizing desktop and server virtualization.
• 2000s onwards, cloud and scaling: Virtual machines have become a foundational technology for modern computing, powering scalable, remote infrastructure and enabling the rise of cloud computing for businesses worldwide.

What are the key types of virtual machines?

Virtual machines are typically categorized as either process virtual machines or system virtual machines:

• Process virtual machines (application virtual machines) are designed to run a single application, and the virtual machine terminates when the application closes.
• System virtual machines (hardware virtual machines) simulate full operating systems and run independently of user activity. These are the most common type of virtual machines. 

Both types of virtual machines rely on hypervisors to manage their operation and resource allocation. For example, a system virtual machine uses a hypervisor to emulate an entire operating system environment, while a process virtual machine may use a hypervisor to isolate and manage a single application. The choice of hypervisor type — Type 1 or Type 2 — depends on the deployment environment and the level of control or isolation required.

Within these two primary categories of virtual machines, smaller subsets include:

• Java virtual machines, which execute Java bytecode.
• Python virtual machines, which work to execute Python code.
• iOS virtual machines, which are designed specifically for Apple systems.
• Android virtual machines, which are designed to work for Android phone systems.

How are virtual machines used?

Virtual machines are a foundational technology across industries, supporting a wide range of applications from software development to enterprise cloud infrastructure.

Software development and testing

Virtual machines enable developers to create isolated environments for building and testing new applications. By simulating different hardware and software configurations, virtual machines allow teams to test software safely, without impacting production systems or risking the stability of the primary operating system. This flexibility accelerates development cycles and improves software quality. 

Cloud computing

Virtual machines are essential to modern cloud computing. ​​They power scalable, remote infrastructure services such as infrastructure as a service (IaaS) and software​ as a service (SaaS). 

By allowing multiple virtual environments to run on shared physical hardware, virtual machines make it possible for organizations to deploy, manage and scale applications efficiently in the cloud.

Remote work and VPN access

With virtual machines, users can securely access company systems and sensitive data from anywhere in the world. Virtual machines make it possible to run applications that may not be compatible with a user’s primary device, and they support secure connections through company virtual private networks (VPNs), enabling flexible and productive remote work.

Running multiple operating systems

Virtual machines allow users to run multiple operating systems such as Linux, Windows or others on a single physical machine. This capability is invaluable for developers, testers and organizations that need to support diverse software environments or legacy applications.

Cybersecurity and access control

Virtual machines provide segmented, isolated environments that enhance security, monitoring and access transparency. Organizations can monitor usage within each VM, enforce granular access controls and ensure that only authorized users can reach sensitive systems, strengthening overall cybersecurity posture.