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I need someone to explain me what EDC (error detection and correction) is.

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SalisMan

OK, I have a choice to get a PS1 game with EDC or with no EDC, but I don't know what is it.

Does it repairs error on the disc, or it's copy protection?

I heard it's copy protection, but wiki doesn't saying anything like that, maybe it does, but I'm not english so maybe you can understand this better than me.

So which one should I get? What's the difference?

I searched on google for a long time, but didn't find any exciting answer.

Thanks. I hope someone understands that stuff.

1 decade ago*

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12 Comments
schnitzeljaeger

http://www.baetzler.de/vidgames/psx_cd_faq.html

Maybe that sheds some light?

1 decade ago
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Brotbaum

I found a link to this on the Wikipedia page under "Data Storage". Maybe that has something to do with it.

1 decade ago
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wwfarch

Get it with EDC, it should be more robust. Basically EDC ensures that even if some of the data is lost the console can figure out what the missing data was.

1 decade ago
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wwfarch

Actually I'm looking into this more. It looks like it IS just be a form of copy protection for the PSX. There's a section of the disc that the PSX checks for an EDC code. If that code is there it assumes there's a valid disc present. If the code isn't there then it assumes it isn't a valid copy.
Basically, a PSX without a mod chip won't run the disc without an EDC code. I assume you're using an emulator in which case it shouldn't matter from what I've read so far.

1 decade ago
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SalisMan

Yeah, that's what I was trying to say in my post below, but just badly... Yeah emulator, but the question is, it is just a protection? It looks like it's more that just that. Like it maybe detects and repairs errors, and this may be took like a error. -> There's a section of the disc that the PSX checks for an EDC code. If that code is there it assumes there's a valid disc present. If the code isn't there then it assumes it isn't a valid copy.

If you understand me.

Also wiki talks about more reliable data delivery or something, data errors...

1 decade ago
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wwfarch

EDC in general relates to error correction. This error detection/correction was used on the PSX as a form of copy protection. When the disc is created the data is scanned and an error correction code is created. This code is then printed to a special section of the disc that most CDRs can't read or write to. When the PSX boots up it looks for the code on the disc. If the code isn't there or it's invalid then the game won't boot.

I think the code really only matters for hardware versions of the PSX. When using an emulator I'm pretty sure you can get by either way.

1 decade ago
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SalisMan

I hope you're right, your answer is like the most explained I saw. I tried Crash Bandicoot 2 with EDC and no EDC, both works. Both are at the same file size. After all, I never get a chance to have PlayStation again and original games for it, so it doesn't matter if I pick EDC version. Maybe it relates to error correction and protection on PSX at the same time? If it is more than just a protection, I should pick EDC version, because I will be able to run it anyway. If it is just protection, then better choice will be no EDC version. But like I said, I will never have PS1 and PS2 again anyway. I'm just precise about what I buy and choose. Always trying to choose the best from it.

1 decade ago
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Brotbaum

Does it matter when you use an emulator? Even when the EDC is for error correction on the disc it wouldn't make a difference when you just make an image of the CD and then play it in the emulator

1 decade ago
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SalisMan

I'm planning to make back up of them. Burn them on the disc.

I'm going to sleep, I'm tired, I will respond later. Thanks for the help wwfarch and others.

1 decade ago
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wwfarch

As I mentioned earlier, most CD burners won't burn the EDC code to disc anyway. At least that was the case years ago but I doubt thing would have changed. IIRC the code was actually stored on the inner ring of plastic.

1 decade ago
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wwfarch

It really doesn't matter for your case (as evidenced by playing Crash Bandicoot succesfully both ways). It's tough to explain at a high level precisely what it is because it's a very technical topic (I have degrees in Computer Science and Math). On the PSX they've taken something that has one purpose (error detection and correction) and used it for something else (copy protection).

I'll try to explain using an analogy. Consider something like a club/bar. The bouncer of the club is the PSX hardware, your license/ID is the EDC code, and the club itself is the actual game data. When you arrive at the club the bouncer is going to stop you and check your ID. If you don't have an ID or your ID is invalid/fake he won't let you in. If your ID is valid he does let you in. Remove the bouncer from the situation and it no longer matters whether or not you have your ID with you. In this case, using an emulator is the same as removing the bouncer from the club. Your ID (EDC/ECC) still has a purpose outside the club but it doesn't do anything else for you once you're inside.

My analogy certainly isn't perfect but it's the best I could come up with.

TL;DR: It doesn't matter if you're using an emulator. It's not used for error correction by the PSX hardware. The PSX hardware is only doing a validity check at bootup.

1 decade ago
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SalisMan

OK, thank you for your help! I'll download the non-EDC version then, now I know it doesn't matter anyway, I thought it detects and repairs errors too, but looks like you know what are you talking about and you know something about that. Or it is based on what did you saw on the internet from the other people what are you saying? I thought it could be error detection and correction + copy protection at the same time, but it's just probably that protection like you said. I hope you're right, it would be better to have error detection and correction on a CD to repair errors automatically. Thanks again for the help! I'm sure some of my downloaded PS1 games has EDC and some don't anyway.

1 decade ago
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Closed 1 decade ago by SalisMan.