Do CDs have any unique ID?

Question

I have a PC game CD twice here. The ISO images on the disks are matching exactly.

Is there any unique ID on the disks which make it possible to distinguish between them?

Somewhere in the meta data?

There is nothing special I want to achieve. I am simply interested in it.

I hope it's clear what I want to do. I want to distinguish two CDs which are carrying the same data.

If the ISO files matches then there isn't and can't be any difference. — ChanganAuto, Commented May 22, 2023 at 9:03
@ChanganAuto Are you sure? There can be more than an ISO on a CD. For example additional audio tracks... — javanerd, Commented May 22, 2023 at 9:09
Sure, CDs can have quite some data that is not part of the user data area. Also, check this—it may not even be digitally readable. — Daniel B, Commented May 22, 2023 at 9:25
"Is there any unique ID on the disks which make it possible to distinguish between them?" - No; It's not possible to distinguish to identical copies of an ISO. — Ramhound, Commented May 22, 2023 at 14:27
@ChanganAuto it may not be a "unique identifier". The point here is that ISO dumps that are identical merely means that the their source media give the same ISO dump. The ISO dump may not necessarily be all the data that exists on the media (and I am not referring to carving or whatsoever, but the fact that direct read with e.g. dd does not necessarily give you everything on the disc). (Direct might not be the right wording but you get the sense.) — Tom Yan, Commented May 23, 2023 at 5:15

music2myear · Accepted Answer · 2023-05-23 04:43:26Z

1

If a publisher wanted to do this, nothing is stopping them, except...

Bulk disk creation is essentially stamping the disks, so duplicate content doesn't really fit into that method.

To write unique values to each disk means writing each disk individually: possible, but not commonly done.

answered May 23, 2023 at 4:43

music2myear

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