Museums expend a large amount of effort and money in determining the originality of the artifacts they hold. Just imagine what would happen if people today only recently realised that a famous work of art had been altered by another artist. Uproar. They probably wouldn’t be able to do anything about it but at least they know, and the value attached to such work would be modified accordingly.
Artefacts that have been altered in any way are not how they were originally intended to be, and thus the value of such items is questionable at best, and worthless at worst.
The extent of damage can often be determined in physical cases. But software is not meant to be modified, any such activity renders the item completely worthless since you will never be able to tell with absoulte surity that the software even works past a certain point, or after a particular action, or combination of actions.
Therefore, authenticity should be paramount in the minds of software preservationists.
Errors can *sometimes* be dealt with. You may be able to apply special treatments to the disks to get a working copy. However, if a disk is modified, there is nothing you can do to salvage it. It is irreparable. 1)
Sources of modification include save games, hi-score saves, virus damage, user hacking, piracy, etc. The list goes on. Probably one of the reasons it is so prevalent is due to the way disks were manufactured with the write protect tab in the unprotected position! Annoying really, since the duplication machines didn’t care whether a disk was write protected or not.
Modified disks are quite common (as are errors). The real scale of modified disks submitted to the project is quite shocking. So if you cannot determine that a disk is unaltered and true to its original mastering then there is no point in trying to preserve it. All it does is create a false sense of security that the item is safe, when in fact, it isn’t.
On some systems like the Atari ST, the problem is even worse due to the ease of programming save routines. We have seen up to 2 in every 3 disks being altered after they they were produced from a sample of several hundred.
In an attempt to fix broken disks by errors, virus damage or whatever, the game owner may have decided to copy another version over the disk. If the user then sells his collection on, a new owner is not likely to be aware of it. In the case of cracks, it’s pretty obvious, but in the case of a hardware copy 2) this fact is hidden.
Any game found to be altered is rejected from our preservation process. The same can be said for copies.
We can check the authenticity because of the nature of the magnetic medium. Since floppy drives are a mechanical device, they make unique “finger print” when they write data. This is similar in concept to the way that law enforcement agencies match printed paper to the printer that printed it. In the same way, we could match a disk to the system that wrote it. Not only that, but the commercial duplication hardware used very high quality components, and so the disks written by such equipment look very different to that of a disk written by a home computer system.
99.9% of the games we have seen so far have been mastered with high quality commercial equipment. The reason for this is actually because it was cheaper to get a game duplicated professionally than it would have been to buy the blank disks and do it themselves.
In the very rare case that was actually mastered on a consumer-level system, we would still be able to see if some tracks were later written with a different drive. Since mastering on consumer level equipment is so rare, disks produced from such a process can only really be confirmed by contacting the developers, which we have done, and will continue to do when necessary.
Our technology process guarantees that every preserved piece of software originates from media that is “factory new”. This involves checking (done almost completely automatically) that each disk is not counterfeit, and has not been altered in any way since the original mastering. Being able to distinguish if tracks written by different drives is a very powerful tool in our authenticity crusade, and, since we can see the difference between a high-quality commercial mastering machine, and a home system writing of a disk, we can detect copied disks, which are anything but authentic.
Data integrity and data authenticity are very important to us and so we give these things very special attention. We could have started imaging games a full two years before we did without taking these things into account, but it would not have been preservation, and it would have been pointless.