How to Use DOSBox: A Beginner's Guide

DOSBox is the emulator that powers most MS-DOS games on GamesNostalgia. When you download a game from our site, DOSBox is already configured and bundled inside the wrapper — you just double-click and play. But if you want to run games from your own collection, understand what's happening under the hood, or fine-tune the configuration, this guide walks you through everything from scratch. We'll use Doom 2 as our example.

Step 1 — Download and Install DOSBox

If you haven't installed DOSBox yet, go to our Emulators page and follow the link to the DOSBox home page, where you can download the installer for your operating system. On Windows, run the installer and follow the steps — DOSBox will be installed in your Program Files folder. On Mac, the easiest option is Homebrew. Open Terminal and run:

brew install dosbox

If you don't have Homebrew installed yet, visit brew.sh and follow the one-line installation instructions first.

After that, launch DOSBox to see if it works. You will see a screen like this.

Close it for now, because we need to download our game first.

Step 2 — Find and Download Doom II

We'll use GamesNostalgia's Old Games Download search engine to find the game. Head to the Old Games Download page and search for "Doom 2". The search engine covers over 55,000 titles and will show you where the game is available. For Doom II, you'll be directed to the Internet Archive at archive.org, where the game can be downloaded for free.

Download the file — it will typically arrive as a .zip archive.

Step 3 — Extract the Game Files

Once the download is complete, extract the .zip archive into a folder on your computer. The location doesn't matter much, but it helps to keep all your DOS games organised in one place. Good choices might be:

Windows: C:\OldGames\Doom2

Mac: /Users/yourname/OldGames/Doom2

After extraction, open the folder and have a look inside.

You're looking for executable files — typically files ending in .exe or .bat. In the case of Doom II, the main executable is doom2.exe. This is the file DOSBox will need to run.

Step 4 — Launch DOSBox

On Windows, open DOSBox from the Start menu or your desktop shortcut. On Mac, if you installed via Homebrew, open Terminal and type dosbox to launch it.

You'll be greeted by a black window with a command prompt — this is DOSBox emulating a DOS environment. It looks unfamiliar if you've never used DOS before, but you only need a handful of commands to get a game running.

Step 5 — Mount the Game Folder

DOSBox doesn't automatically see your computer's files. You need to tell it where your game is by mounting a folder as a virtual drive. Type the following command and press Enter:

Windows: mount C C:\OldGames\Doom2

Mac: mount C /Users/yourname/OldGames/Doom2

This tells DOSBox to treat your Doom2 folder as the C: drive inside the emulator. You'll see a confirmation message: *Drive C is mounted as a local directory*.

Step 6 — Navigate to the Game and Run It

Now switch to the virtual C: drive by typing:

C:

You should see the prompt change to C:\>. If your game files are directly in the mounted folder, you can run the game immediately. If they're in a subfolder, navigate there first with cd gamefolder. But in this case it won't be necessary.

You can launch the game by typing the name of the executable:

doom2

Press Enter, and Doom II will start.

Step 7 — Automating the Launch with a Configuration File

Typing the same mount and navigation commands every time you want to play is tedious. DOSBox solves this with configuration files — plain text files that can contain a section called autoexec, where you place any commands you want DOSBox to run automatically on startup.

Create a new text file in your OldGames folder and name it doom2.conf. Open it with any text editor — Notepad on Windows, TextEdit on Mac, or anything else you prefer — and add the following:

[autoexec]
mount C C:\OldGames\Doom2
C:
doom2

Save the file. Remember to use the proper path for Mac. Now, instead of launching DOSBox and typing commands manually, open a terminal or command prompt, navigate to your OldGames folder, and run:

dosbox -conf doom2.conf

DOSBox will start, execute every line in the autoexec section automatically, and launch Doom II without any further input from you.

This is exactly how GamesNostalgia wrappers work under the hood — each game comes with a pre-written configuration file that handles mounting and launching automatically. Now you know how to create the same setup for any game in your own collection.

Step 8 — Configuring DOSBox with dosbox.conf

So far, your doom2.conf only contains the autoexec section. But DOSBox has a full configuration file that controls everything from screen resolution to CPU speed and sound settings. To generate a default configuration file with all available options, run this command inside DOSBox:

Mac: config -writeconf /Users/me/OldGames/dosbox.conf

Windows: config -writeconf C:\OldGames\dosbox.conf

This creates a complete dosbox.conf file with every setting listed and commented. Open it in a text editor — it's long, but well organised into sections.

For most games, you'll only ever need to touch a handful of settings. Here are the most useful ones.

Fullscreen mode

By default, DOSBox runs in a window. To make it launch in fullscreen, find the sdl section and change:

fullscreen=false

to:

fullscreen=true

You can toggle fullscreen at any time while playing with Alt+Enter, but setting it here means you won't have to do it every time.

CPU speed (cycles)

If a game runs too slowly, the most likely cause is that DOSBox isn't allocating enough CPU cycles. Find the cpu section and look for the cycles setting. The default is auto, which works well for many games but not all. For Doom II and most early-to-mid 1990s games, a value of 20000 is a good starting point:

cycles=20000

If the game still feels slow, try increasing the value. If it runs too fast — which can happen with older games from the late 1980s — reduce it. You can also adjust cycles on the fly while playing with Ctrl+F11 (slower) and Ctrl+F12 (faster).

Scaler

The scaler controls how DOSBox scales the original low-resolution image up to fit your screen. The default produces a sharp but blocky result. If you prefer a smoother look, find the render section and change the scaler setting to:

scaler=advinterp3x

This applies a smoothing filter that softens pixel edges without blurring the image too much. It's a matter of personal taste — some players prefer the sharp original look, others find the smoothed version easier on the eyes.

Using the settings in your game config

Once you've edited dosbox.conf to your liking, you can tell DOSBox to use it alongside your game-specific file. Simply reference both when launching:

dosbox -conf dosbox.conf -conf doom2.conf

DOSBox reads configuration files in order, so doom2.conf will apply on top of the base settings — the autoexec commands in doom2.conf will still run last and launch the game.

For the full list of configuration options — including sound card settings, memory management, joystick support, and more — refer to the official DOSBox documentation at dosbox.com. The file generated by config -writeconf is itself well commented and a good reference on its own.

What's Next

This guide covers the most common scenario — games that run directly from a folder with no installation required. Doom II is a good example, but many DOS games from the mid-1990s onward are more complex: they come as CD-ROM images, require a setup program before they can be played, or need both a mounted hard drive and a CD drive to run correctly.

If your game falls into that category, head to Part 2 of this guide - to be published very soon - where we cover CD-ROM images, the setup and installation process, and how to handle games that need both a C: drive and a D: drive to run.