How does a game know if "The Disc Cannot Be Read"?

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Drew Sebastino
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How does a game know if "The Disc Cannot Be Read"?

Post by Drew Sebastino » Fri Aug 12, 2016 2:58 pm

Okay, so I had a copy of Super Smash Bros. Melee that I let someone I know "barrow" a number of years ago, but now that he's gone off to college so I got it back. I put it into my GameCube, but it tells me that "The Disc Cannot Be Read". I take it out and look at the disc, and I notice there are a couple of pretty deep scratches, and knowing the game is messed up anyway, I figure I'd get a very mild abrasive and try to get them out at the cost of putting in a million smaller ones. (Maybe not my best idea ever...) The deep scratches are still kind of there, but I put it in and the game went to the title screen and then prompted me that it couldn't read the disc. Then, I rubbed it for another very long time to where the disc has no trace of heavy scratches but a light haze on it from all the microscopic scratches on it. I put it in and I get past the title screen to the main menu and try to start one player, but it complains again that the disc couldn't be read, so I just took out the disc, wiped it off, and put it back in and it worked. It then displayed that error message every time the game would load (which is even when the game is telling you what your score is at the end of a fight, oddly enough) and I got lazy to the point where I wouldn't even take out the game, I'd just lift the lid and put it back down again, and, despite me never even touching the disc, it would miraculously work. I don't even have an explanation for that. I can access every part of the game I tested, I'd just have to open and close the lid about 2-3 times to get it to work.

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HVC-Man
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by HVC-Man » Fri Aug 12, 2016 3:08 pm

I'm no expert in the hardware and firmware of the Gamecube, but if it's anything like other consoles or the Wii...

Either the "Disc cannot be read" text comes from the Gamecube firmware, or the boot/executable files on the game disc that are loaded first before the game itself. Consider that the Gamecube boot screen appears with the logo, it fades to black, then either the game starts playing (or asks to run in progressive scan mode) or it prints "disc cannot be read" to the screen.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by thefox » Fri Aug 12, 2016 3:12 pm

There are error correction codes (ECC) and checksums embedded in the disc data. If the errors are not correctable and/or the checksums don't match => "the disc cannot be read".

The primary cause can vary, of course.
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Drew Sebastino
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by Drew Sebastino » Fri Aug 12, 2016 3:16 pm

HVC-Man wrote:I'm no expert in the hardware and firmware of the Gamecube, but if it's anything like other consoles or the Wii...

Either the "Disc cannot be read" text comes from the Gamecube firmware, or the boot/executable files on the game disc that are loaded first before the game itself. Consider that the Gamecube boot screen appears with the logo, it fades to black, then either the game starts playing (or asks to run in progressive scan mode) or it prints "disc cannot be read" to the screen.
The thing is is that this can happen anytime during the game, not just at the booting screen. I wonder, is the disc drive handled by hardware or software?
thefox wrote:There are error correction codes (ECC) and checksums embedded in the disc data. If the errors are not correctable and/or the checksums don't match => "the disc cannot be read".

The primary cause can vary, of course.
How can the error correction codes tell what is an error vs regular data? I wish there were a way to override it or something and try to play the game, although it would probably crash.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by tepples » Fri Aug 12, 2016 3:30 pm

As I understand it: The drive's microcontroller calculates the error correction and returns either a 2048-byte sector or an "I/O error" status. The software is responsible for retrying, and if several tries to read the same sector all produce "I/O error", the software (either the console's firmware or the game's executable) will display the error message.

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HVC-Man
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by HVC-Man » Fri Aug 12, 2016 3:36 pm

Espozo wrote:How can the error correction codes tell what is an error vs regular data? I wish there were a way to override it or something and try to play the game, although it would probably crash.
I don't think there's a way to override an I/O error, not unless you want the game to crash.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by mikejmoffitt » Fri Aug 12, 2016 4:19 pm

HVC-Man wrote:
Espozo wrote:How can the error correction codes tell what is an error vs regular data? I wish there were a way to override it or something and try to play the game, although it would probably crash.
I don't think there's a way to override an I/O error, not unless you want the game to crash.
The closest thing to an override is to trigger a re-read attempt. If the disc is barely working, opening and closing the lid effectively resets the retry counter, letting it maybe get the data it needs to proceed.

I have an old Melee disc that has a nasty scratch on some data related to the game's initial boot-up. A few good retries and I can get past the title screen, and it's fine from there on.

This sort of thing may have been more common with earlier disc systems if their practices weren't so shitty. Some Sega CD games will just try to load the data, expect it to work, and if there's a problem they'll just sit there without a message, or any attempt to reinitialize the disc, or open the tray, etc. Games like Melee offer a much better experience through a robust design.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by NYMike » Fri Aug 12, 2016 5:03 pm

I know this thread is more of the technical side but I figured I would chime in. I fool around down at a local retro shop and we have nothing but trouble with Gamecube scratches. Almost every other system you can just stick up to a grinding wheel with a cotton buff pad and it will fix almost any issue. For whatever reason, this makes Gamecube games usually not work. If you do decide to go this route, go super light and do minimal buffing possible or there is a specific Gamecube buffing pad you can purchase.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by Jedi QuestMaster » Sat Aug 13, 2016 12:01 am

Just curious, Espozo... do you have a Wii to test this on? Do you get similar results?

Off topic, my copy of Brawl always freezes every single time on the stage select screen, and only on the stage select screen. It's a good thing I'm not fussy about which stage we're playing and just leave it on Random.

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HVC-Man
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by HVC-Man » Sat Aug 13, 2016 12:52 am

That's not really a problem at all, Brawl is a horrible game, one of the worst Nintendo developed and/or published on the Wii.

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Drew Sebastino
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by Drew Sebastino » Sat Aug 13, 2016 9:17 am

HVC-Man wrote:Nintendo developed and/or published on the Wii.
I think you're forgetting how crappy the Wii's library was...

Also, you're forgetting how fun Brawl hacking is. :wink: (Although SSB4 seems to be making that obsolete.)
Jedi QuestMaster wrote:Just curious, Espozo... do you have a Wii to test this on? Do you get similar results?
I have a Wii, but unfortunately, this beast is in the way:
Because HDTVs have poor analog support....png
I put my Wii in the closet because I didn't think I'd need it because the Wii U can play Wii games.

Also, while I was looking through my camera, I found this. I didn't think Stef played Splatoon. :lol:
Someone familiar....png
It is quite odd though. I looked at my Super Monkey Ball 2 disc, and it's got smudges and deep scratches all over it, and not once has it given me a disc read error. What the hell. I could even show you the difference if toothpaste weren't drying on my Super Smash Bros Melee disc for the 100th time. :?

It works a little better now, but man, what a scratched piece of garbage this Super Smash Bros Melee disc is. :roll:
GameCube is picky af.png
I even wiped of the lens of the GameCube with my glasses wipe to no avail.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by calima » Sat Aug 13, 2016 10:50 am

I'd just pirate a copy for the Wii. You have the disc, and trying to fix it is a hopeless endeavor. Nintendo replaces discs IIRC, but at some cost.

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Drew Sebastino
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Re: How does a game know if "The Disc Cannot Be Read"?

Post by Drew Sebastino » Sat Aug 13, 2016 11:12 am

calima wrote:I'd just pirate a copy for the Wii.
Not if I want a notice from AT&T. :?
calima wrote:Nintendo replaces discs IIRC, but at some cost.
Even old GameCube discs? You know what I'll do? I'll go to the game store, and see if they have it there, and then compare it to the cost of having the disc replaced by Nintendo.

Actually, I'm out of luck with Nintendo...
•If the game is published by Nintendo and it was purchased more than 90 days ago, or you do not have a proof of purchase, we cannot offer a warranty repair. (This also includes games that were purchased used or that are physically damaged.) We recommend purchasing a replacement copy of the game at a retailer.
Actually, the Game Exchange near me has a disc repair machine. I doubt it'll work, but it's worth a shot. If it doesn't work there, then I can just buy a new one there because they offer to test the games.

Thanks for everyone's help though, and I'll tell you if I get it to work or get a new copy. The disc is just a bitch. :lol:

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by NYMike » Sat Aug 13, 2016 2:02 pm

So in case you did not know, Game Stop has been selling older system games on their website but can still be looked up and ordered in store. Returns can be returned in store for cash or credit as well. Not condoning anything but most can put 2 and 2 together with this post.

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Re: How does a game know if "The Disc Cannot Be Read"?

Post by NYMike » Sat Aug 13, 2016 2:04 pm

Actually, the Game Exchange near me has a disc repair machine. I doubt it'll work, but it's worth a shot. If it doesn't work there, then I can just buy a new one there because they offer to test the games.
I assume this shop knows what their doing but again don't just let them stick your game up to a standard buffing pad attached to a grinding wheel. Like I said this will 90% ruin the game. A specific Game Cube buffing pad exists.

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