Not sure why you say "unnecessary complex to use CAPS images"...? Dumping disks is quite straight forward. Perhaps slightly more involved that creating ADF's but that is more due to ensuring a system is is in "good health" before dumping anything, quality assurance and all that. Sure, the technology is complex, but the user doesn't need to see any of that.
Anyway. Yes. I mean that even if you have an original disk, it does not mean that you have an original game.
It might be:
1) A copy. Perhaps the disk stopped working and a previous owner copied over it with another disk (even if original). It may still be the original data - but you can no longer be sure, what if something happened to the source disk before it was copied? Even we could not determine if the original disk was modified in this case, because the modifications are "hidden" by the copying - since it was then all written with the same system. (see below about how we detect this)
2) What if your copy has had suffered virus modification/damage? It doesn't have to be be actually infected. What if a previous user saved their games or hiscores to the original? All this means the copy is no longer authentic.
3) If a previous owner mucked about with the disk/game data, it might no longer work properly. This is pretty unlikely without it being an obvious crack, but it does happen.
So, all in all, you may *think* you have an original authentic copy - but you may actually not at all. Copies which are "flawed" from a preservation point of view (as above) should not be regarded as a digitally preserved copy of the game.
You may very well have an authentic copy, but for all the above reasons, we prefer to be sure about it.
In a real situation: Once recent contributor was "sure" all his (unfortunately rare) disks were authentic since he bought them new, but unfortunately most of them had been modified. This unfortunately happens all the time. Therefore, preservation should not be limited to games that are copy protected, we regard all games the same.
Even so, if it doesn't have disk protection, read errors would be detected by ADF imaging.
Possibly. But we could also say that due to the way we read the disk, we are far more likely to be able to get a good read of "hard to read" tracks.
Or does CAPS have some magic forensic technology that shows modifications?-)
Not magic, but it is very likely the same techniques have been and/or still are used in forensics, yes. On a conceptual level, it is like how it is possible to match a printed page to a printer - we could match a disk to the system that wrote it.
Very basically, since a disk drive is a mechanical analogue device, each system will leave its own "fingerprint" when writing, that is, each system will have their own identifying "crackles and pops" in the "way" they write data. A commercial mastering system uses high-quality components, and so the "fingerprints" look very different, but even if a game was mastered with an Amiga (very rare, but has happened) then we can still see if it has been modfied by another machine.
For more information, please read:
http://www.caps-project.org/articles.php?id=modified
We have actually found a game that we know was "officially modified", Little Computer People. This one certainly confused us for a while... We eventually had to verify the authenticity by contacting the author. You can read the whole report here:
http://www.caps-project.org/articles.php?id=a_lcp
I hope this explains it all better, and I apologise if my previous answers were a bit too vague!
. So I started to play with it. And needing samples and stuff, I learned to rip games' files. And learned a little music through making nice covers and remixes of every game music I could grasp. Then came Noisetracker, Protracker, Startrekker, OctaMed, and so on. 