What Is an Emulator?

The tech that lets computers copy each other

A smartphone OS running on a computer monitor

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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 someone might use them.

What Is an Emulator?

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

Today, the term emulator is commonly used in the context of video games. Video game emulators became popular during the 1990s because they allowed people to play games for consoles like the Nintendo Entertainment System and the Atari 2600 on modern desktop computers. With the proliferation of smartphones and tablets, emulators capable of running iOS or Android on PCs have been in increasingly high demand.

How Emulators Work

There are different types of emulators that employ various emulation techniques, but the end goal is the always same: To replicate the experience of using the original hardware or software. Some emulators even exceed the performance the original product and include additional features.

Emulation requires a lot of computational resources. Due to this "emulation tax," many emulators lag behind their real-world counterparts in terms of performance. Since they are usually created by unpaid programmers, 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 can run on the underlying hardware of the host system. Therefore, there is no emulation tax, but virtual machines can be limited in what they can do as compared to the original machine.

Why Use Emulators?

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

Emulators also play an import 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 it was designed for.

Examples of Emulators

There are countless commercial and open-source emulators available for every major operating system. For example: