I'm 45, and I've been gaming on consoles since the Magnavox Odyssey. Many of the games I've played over the years represent a huge investment of time and a huge return of pleasure in playing, so I keep them. I keep them on shelves in my office, I keep them in bins in my basement. I don't get rid of them for the same reason I don't toss my old vinyl albums or CDs — in many cases, there's a real emotional attachment.

But this isn't about my hoarding tendencies. It's a good thing I've kept those old games around, because now I can play them again on my Mac. A powerful application provides the framework to do it easily, and it's absolutely free. It's called OpenEmu, and here's how to use it.

Emulators and ROMs

Let's talk a little bit about emulators themselves: Emulation software has long existed on the Mac, letting users play video games developed for older console systems. Whether it's a Nintendo Game Boy cartridge from your childhood or a Sega Genesis, Atari 2600 (for you old-school gamers), or dozens of other systems, chances are an emulator exists to run the platform's games.

Emulators are perfectly legal to use (at least in the United States, where I live), as long as the developers don't include the proprietary system BIOS files that the game console makers wrote. And many emulators manage to work fine without such files.

Of course, emulating a device is one thing. Getting the software to work is quite another. The games themselves need to be transcoded into ROM files — memory dumps of game cartridges and discs. That's also where the legal waters get muddy.

Like DVD rips, the general rule of thumb is to only use ROM files for games you actually own. If you download files for games you don't own, it's software piracy. Distributing ROM files is discouraged, of course, but that hasn't stopped many websites from hosting them.

OpenEmu makes available a "Game Starter Pack" of homebrew games — games that weren't released commercially — designed to work on the various systems. So you can get a taste of how OpenEmu works without having to hunt for ROM files, if any of this sounds too sketchy for you.

Sorting things out

Before OpenEmu came along, I had a mish-mash of different emulation apps on my Mac. Now, I just use a single app that controls it all. Drag and drop ROM files into the app, and it automatically catalogs them and even adds cover art when available.

ROM files don't always work the way they're supposed to, and emulators sometimes don't as well. It's as much art as it is science when it comes to making this technology, and it's not always exact. As such, sometimes you'll come across a game that just won't play right. But the experimentation is worth it, because there are so many cool games worth playing.

The genius of OpenEmu is that it gathers different emulators and ROM files together to make it much easier to play and sort your games. No more manually sorting through folders in the Finder. And while you're still on your own when it comes to finding commercial game ROMs, all the major emulators are included.

OpenEmu also supports game controllers: Any game controller that's compatible with the Human Interface Device (HID) specification will work. That includes many USB controllers, including some Nintendo, PlayStation and Xbox controllers, Logitech and Gravis gamepads, and more. You can manage specific button configurations and other customizations in OpenEmu's preferences.

At the moment, OpenEmu supports ROMs for the Game Boy Advance and Color, NeoGeo Pocket Color, NES, SNES, Sega Game Gear, Master System and Genesis, and others, with new open-source and publicly licensed emulation cores added periodically. The original Atari 2600 was recently included, utilizing the Stella emulation core. If you're interested in what they have planned for the future, check out the list: Commodore 64, Vectrex, even ColecoVision are on the list, and some of them are already usable.

The Good

Includes emulation cores for many popular older console systems
Integrates ROM file management
Supports game controllers

The Bad

Some ROM files don't work, your mileage may vary

The Bottom Line

OpenEmu is free and makes running ROMs on your Mac fun and easy. If you have game cartridges in a dusty box somewhere in your home that you haven't played in years, this is a great chance to get reacquainted with them and rediscover how much you really love gaming.