I own old gaming consoles such as the Nintendo DS. The consoles have aged significantly and they have a hard time recognizing legit cartridges, so I dumped the contents of dozens of carts on a 3rd party cartridge, which is legal as long as I own the games. I no longer had to blow my carts 50 times before booting a game, nor did I have to dig through a huge pile of carts every time I wanted to play a specific game.

One day my friends came over for a LAN party. I tried to setup a mario game for two Nintendo DSes with one cartridge. This requires using the built-in Download Play feature but it didn't work so I booted the legit cart on one console and the 3rd party cart on the other. My friend jokingly said that we are technically pirates now since I had only one legit copy of the game but we are running two instances of them at the same time. Is this true? If I have n physical copies of a software, is it illegal to have more than n instances running at the same time?

If so, does installing Microsoft Windows on multiple computers from a single installation media constitute piracy in the same way?

  • 2
    Windows gives the install media freely and has keys, so is different.
    – Trish
    Commented Dec 18, 2023 at 14:00

1 Answer 1


As a general rule you are only allowed to copy or run software in accordance with the license you were granted when you bought it. So the answer is to be found there. Anything not allowed by the license is prohibited by copyright law, with some exceptions (see below).

A quick look on the Nintendo DS support page doesn't find anything. You might find it inside the game documentation somewhere. In all likelihood it will prohibit any use of the software other than playing the game from the original cartridge, so you are very likely in violation of the license.

But that's not the end of the story. Legally you can make a backup or archive of the software, so the transfer to a new cartridge is OK. You can only transfer the backup along with the original (e.g. if you sell it).

Using the copy alongside the original in the way you did is likely a violation too, just because there isn't something saying you are allowed to do it. OTOH if this had the same effect as a feature which would create a temporary copy on your friend's console anyway, then that's probably OK (I don't know the Nintendo DS) .

Of course the likelihood of Nintendo caring enough to even write a Cease-and-Desist letter is pretty low, so in practice its not likely to be an issue.

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