How Does Emulation Work?

Key Points:

• One of the most frustrating things about video games is that some of them aren’t available across different systems, which is why emulators were created.
• There are two types of emulators, where one is more accurate to the original and one where it is more of a general mimicry.
• Emulators will need significantly more resources to run than the original hardware.

Video games are designed to work on specific devices or hardware. In other words, if you play a Playstation 2 game, you’d have to insert it into a Playstation 2 device where it would run. If you set that same game into a Playstation 1 or a Windows 10 PC, it won’t run properly. So, what can you do to make the game work? Use an emulator.

Emulation involves running specialized software programs on a device that isn’t meant to run them. For instance, a Playstation emulator makes it possible to play Playstation games on a Windows computer. Many emulators exist, and they allow you to run different types of software. 

What are Emulators Exactly?

An emulator is a software that mimics a piece of hardware precisely. In the case of video games, emulators mimic the game console that originally played the game. A Nintendo 64 emulator uses software to replicate the graphics card, the onboard storage, the available RAM, and all the computations within an original Nintendo 64 device. 

Emulators must replicate all the system hardware, and the calculations precisely. The game communicates with the emulator flawlessly and runs like it would on the original console. This is often difficult, and time-consuming.

How do Emulators Work?

Emulators work by either mimicking the hardware of an old device or by using specialized software that understands how to interface with software that wasn’t originally designed for the system the program is running on. There are two different types of emulation, known as low-level and high-level. You must understand both to answer the question, how does emulation work?

Low-level emulation offers the most accurate play experience for gamers, but it requires the greatest amount of resources to do effectively. High-level emulation tries to offer a play experience similar to the original without worrying about accuracy or sticking to how things were originally done. 

Low-Level Emulation

Low-Level emulation works by mimicking each of the hardware components inside a game console separately and joining all those different parts together inside a single advanced program. 

Most developers agree that emulating the central processing unit of a game console is the most difficult thing to do. Different central processing units, or CPUs, follow a different set of instructions when processing information. These devices also connect with all the other hardware components around the game. 

Low-level emulation offers the most accurate play experience for gamers, but it requires vastly more processing power than what was required by the original hardware. 

High-Level Emulation

Instead of trying to simulate every piece of hardware in something like a Playstation and then simulating all the signals between that hardware, high-level emulation tries to find a way to communicate with a Playstation game. 

The program works to translate information from the game to a format the computer knows how to use. The high-level emulator converts the video information into video files that work on the computer.

It captures the original audio information and converts it into something your device can use. Finally, it converts the CPU information either line-by-line, in big chunks, or by capturing long lists and converting them into commands for the modern CPU.

When these three functions are combined, you end up with a working version of the software program on your device. High-level emulation is necessary to emulate the more powerful systems, and it’s increasingly what software developers are relying on as they move past emulating the oldest systems for the newer options. 

Why are Emulators Released Long After Game Platforms are Released?

Emulators for specific gaming devices typically takes years to come out. Part of the reason is developers must effectively simulate every bit of the hardware within the device for the emulator to work properly. This is time-consuming and complex to accomplish, and a significant amount of reverse engineering is required before a proper emulator can be produced. 

The second reason is that the system that’s running the emulator must be significantly more powerful than the machine that it’s emulating. In other words, if you want to play Playstation One games on your computer, your computer must have a better graphics card, central processing unit, more RAM, and more storage space to successfully run an emulator program.

Emulators Demand Greater Performance Resources

An emulator is a software reproduction of physical hardware on a different system. To properly reproduce the piece of hardware, the device must maintain its own operations while also providing all the power needed to run the virtual hardware for that machine. 

It’s also important to note that emulators aren’t 100% efficient. That means that you’ll likely use more resources to create a software version of a device than you would need in physical hardware. Emulators aren’t as efficient, so you will need significantly more system resources to run an emulator than what was needed on the original hardware. 

Emulators are slower than the original hardware because they must translate the CPU instructions to work on the native CPU that’s actually running the program. In other words, PlayStation uses a CPU that sends instructions in MIPS, and most modern computers use X86 or X64 CPUs today. The emulator must translate those MIPS instructions into X86 or X64 instructions before it can run the program on your computer.

Think of this translation process as a real-time conversion that’s taking place. Making this conversion while the program runs slows things down and demands much more processing power than you would need to run the program using its native instructions.  

Exploring PS2 Emulator Versus Playstation 2 System Requirements

According to Game Console Index, the Playstation 2 originally came equipped with 32 MB of RDRAM for its system RAM and 4MB of eDRAM for its graphics VRAM. To run the full lineup of PS2 games on the PCSX2 emulator, it’s recommended that your computer has 4GB of system RAM available and 2GB of VRAM available.

This is significantly higher than what the Playstation 2 used. If you tried to emulate the system hardware on a device with similar specifications to the Playstation 2, it would never work. 

Why are Emulators Used?

There are many reasons emulators are used today. Still, the most obvious is to run some piece of software, such as a specific video game, on hardware that wasn’t originally designed to run that software. 

For instance, you could play a Playstation game on a Windows computer using an emulator. This same idea applies to software outside of video games as well. It’s possible to use old DOS programs on a current windows system with help from an emulator. This could allow you to use old office software and more without having to have an old DOS-based computer. 

If you have some software that you want to use, and you want to use it without the original hardware it was designed for; an emulator is your best option. 

Run Multiple Programs at Once

Emulators are useful in running multiple software programs at the same time, which may not have been possible on the original hardware. For instance, some emulators allow multiple users to play different games on the same computer at one time.

By loading these games in different windows, and accepting multiple controllers, two or more instances of games for the same system can be used simultaneously. 

This is a less common use case than running software on the hardware it wasn’t originally intended for, but some individuals utilize emulators for this reason. 

Are Emulators Legal?

Emulators are completely legal to own, but that doesn’t mean they are legal to use. There is a lot of a legal gray area around emulation software. Most people agree that it’s fine to use an emulator with a ROM as long as you own the original game or program you’re emulating. 

If you own a Playstation One and you want to emulate Spyro, you would be legally okay doing so as long as you own a copy of that game. If you don’t own the game, then you would be engaging in piracy by running a copy of it on an emulator. 

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The image featured at the top of this post is ©Andrew Magill / CC BY 2.0, Flickr.