I was always curious and wondered how long exactly NES games will remain playable. Right now, 25 years after the first games were released, you can still easily fire up the game as long as its clean and the system you are using is clean. 

i'm not sure if production carts experience bit-rot or not (maybe less so than protos). good question though.

"Computer Space" was created in 1971 and has a TON of EPROMs present. There are plenty still working just fine (I actually had the chance to play one at Fun Spot). If those are still alive and kicking, I would think NES games have a great deal of time left.

*Edit:  I was completely wrong regarding the EPROMs.  I had assumed that the game had EPROMs present when in fact it used TTL chips.  A game like Pacman would better fit my argument, although it is significantly "newer" than CS.

NES cartridges do not contain EPROMs. They contain mask ROMs. Mask rom chips are created by a much different process - the data is stored in permanently "burned" silicon dies - much the same way that logic chips are made. As such, they ought to retain data more or less indefinitely.

EPROM chips, being erasable, store data by means of a stored charge trapped in special gates. This data is very stable, but after 20 or 30 years can fade as the charges dissapate. Again though, EPROMs are very stable, and while "bit-rot" can and does occur, it's not very common.

Some NES games contain batteries (Zelda, Kirby's Adventure, etc). These batteries have a lifespan, and when they fail, will cause data stored in battery-backed RAM to be erased. This only applies to high scores and savegames though, the game program will work fine, and the game can save again once the battery is replaced.

I do not forsee any bit-rot problems affecting cartridge-based game consoles. The only exceptions I am aware of are some 20th Century Fox games for the Atari. For whatever reason, the mask ROMs in those are exceptionally poor quality, and it's not too uncommon to find a game that's dead. This failure is more likely due to the composition of these chips themselves, however, as the legs corrode visibly - I believe the leadframes are made with the silver-plated steel or similar, and the chip is simply corroding from moisture in the air. Sometimes you see this same problem on other chips, epecially TI logic chips from the 70's, Namco custom chips in arcade games (Pole Position, Galaga, etc), and some others. But, again, it's more of a corrosion problem than a bit-rot problem.

Nintedno used exceptionally good quality stuff, and the cartridge boards are well made, as are the mask ROMs. I really don't see any problem with this stuff just firing up and working 50 years from now.

-Ian

Some NES games do have EPROMs, all of the Panesian games for sure have them, and Test cartridges are all EPROMS. I know a few instances of SMB/DH carts have been found with EPROMs as well.

^ Also many WT/BG/CD games, but not all.

True, I forgot that there are a few production carts with EPROMs... those *may* fade at some point, but it's really not a big deal. When/if the EPROM fails, just reprogram it. All those carts have been dumped and the data is readily available.

And, this is another reason why it's vitally important that all prototype/one of a kind cartridges are dumped, and preferably, released. This way, the data will be archived, and will be available in the future.

-Ian

I'm aware of that.  I wasn't trying to imply that NES games contain EPROMs, I was stating that games that contained EPROMs were far more fragile and those games are going strong still (Like a Pacman machine for instance).

I have a huge amount of NES prototypes that contain EPROMs and very few, if any, have show any signs of failure.  I would think a production NES is less likely to fail than pre-production prototype containing EPROMs.  I don't think we have anything to worry about.

The problem with bit rot is how will you know? It is a prototype so you expect differences from the production cart. You have nothing to compare it to, so are those changes in the graphics intentional or by rot? Until you completely disassemble the ROM are the changes in the PRG just random unused data or something important like levels? They may very well last another 50 years from now, but they could also be starting to die right now and you wouldn't know.

i can only speak for myself, but i keep my games in excellent condition, and store them very well, so i would say that they will be playable for the next 100 years plus

Wow, thanks to all of you for the input. Especially you Ian for the very thorough and knowledgeable answer!

So if I get repros they will die before im an old man? The reason I collect, is so when im an old douche bag in a retirement home, that doesnt know how to work the new technology, I can kick back and play my games, and remember my child hood. Or better yet, if I have memorey problems, all my nes games will be new again.. hooray Alzheimer's!

That depends on the repro maker. If they use EPROMs then yes the carts will eventually die. However if they are smart (like me ) they will use one time programmable ROMs that cannot get bit rot. The bits are fuses instead of gates so they can only be blown once.

However chips like the Ciclone are reprogrammable, so it will rot sometime. If you have a cart that dies before I do send it back here for repairs

One time programmable ROMs, as in the OTP 27C256's and the like? Hate to disappoint you, but those aren't true fuse-blow type ROMs, those are exactly the same die that the EPROMs use. They're only OTP because they're in an opaque plastic package and therefore cheaper to make than the erasable ones in the ceramic package with the window.

adding to what dangevin an penguin have already mentioned im pretty sure HES games are EPROMs aswell

Interesting. I'll have to check on that - I have a couple HES games on the way.

Browser crash, heres the short version

Atmel chips are fused based, some of the baking datasheets make the distinction.

Bit rot is an electrical certainty, just nobody knows the time frame. Partially because nobody has actually checked how many carts are already rotting.

forever!!

Are the SMB/DH EPROMs the ones with the black blobs?

Those are on board ROMS, the black guk. Just a different package than the big chips And those some are ones that have EPROMS are repaired AFAIK. And test carts and such have them. And other small games like the early Bible Adventures have them too.

Based on the failure rate of cartridges compared to the failure rate of control decks, I'd say that the lifespan of a single cart is far long than that of a single NES, no matter what is inside the cart.

There's only like 7-8 chips in the NES, that's not that many either to fail. Chips don't die all to often, especially produced later in the decade. And I wouldn't count the connector twords the NES "failure rate" because that's a little different from the actual computer failing.

Who "dumps" the carts and how? Who has access to all that data? Is it just like the roms that play in emulators? What games have not been dumped?

Yeah. I don't know if it's been dumped, I've just never seen it. And they are the ones with a programmer and remove the ROM, or a retrode to dump ROM's, or their own custom device. They can get the data off it, make a ROM, and then someone can also make a mapper for emulators to play it.

This thread makes sad. Sudden death of all our NES carts would be like that Twighligt Zone episode where the guy's glasses break and he can't read any of the books. Actually no... Sudden death of all playable consoles preceeding the death of all the carts would be a Twighlight Zone situation.