What Is an Emulator?

The tech that lets computers copy each other

An emulator is a computer or program that emulates, or imitates, another computer or program. For example, emulators make it possible to run Windows on a Mac computer and vice versa. Learn about how emulators work and why you might use an emulator.

A smartphone OS running on a computer monitor.

What Is an Emulator?

IBM conceived the concept of computer emulation as a way to run programs designed for older devices on newer models. The method IBM used relied on a combination of software and hardware dedicated to emulation. Rather than designing new applications for its new computers, built-in backward compatibility gave developers greater flexibility.

Today, the term emulator is commonly used in the context of video games. The video game emulator became popular during the 1990s because it allowed people to play older console games on modern desktop computers. With the proliferation of smartphones and tablets, emulators capable of running iOS or Android on PCs are also in increasingly high demand.

How Emulators Work

Different types of emulators employ various emulation techniques. Still, the end goal is always the same: to replicate the experience of using the original hardware or software. Some emulators exceed the performance of the original product and include additional features.

Emulation requires many computational resources. Due to this emulation tax, many lag behind their real-world counterparts in terms of performance. Since unpaid programmers usually create them, emulators can take a long time to develop.

Emulation is closely related to the concept of virtualization. Virtual machines are a type of emulator that run on the underlying hardware of the host system. Therefore, there's no emulation tax, but virtual machines are limited in what they can do compared to the original machine.

Why Use Emulators?

Software tends to be platform-specific, which is why developers make separate applications for Android, iOS, Windows, and Mac. If you're a Mac user and want to use an app that's only available for Windows, your only option (besides buying a Windows computer) is to use an emulator.

Emulators also play an important role in digital preservation. Programs stored on obsolete formats, such as old game cartridges, can be downloaded as ROM (read-only memory) files using a special device. The ROMs can then be played using an emulator for the original game system they were designed for.

Examples of Emulators

There are countless commercial and open-source emulators available for every major operating system. Here are some examples:

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