Blog:Code Comparisons Like Mom Used to Make
Dimitri recently used CloneSpy to look at Game Boy (regular, not color) games. In case you don't know, CloneSpy is a code comparison program that predates our own; it was originally written by Thomas Jentzsch back in 2000 and was aimed at sorting out Atari 2600 ROM dumps.
There are significant differences between CloneSpy and our program. Our program only looks at two files at a time, while CloneSpy goes over all files in a directory. Our program writes shared data like hex strings to an output file. The user then has to search for that data on his or her own in other files, perhaps using a program like Effective File Search. CloneSpy does all this itself, but it's a mystery as to what shared code is being found unless you want to disassemble the ROMs later and investigate for yourself. This may not be a big deal when it comes to 2600 games, but it becomes a problem when dealing with more complex games. For example, CloneSpy grouped together puzzler Rock'n! Monster!! and Super Street Basketball. Upon further examination, it turned out both games were by different developers, but they do share a music composer, which means they likely share the same sound driver. That likely triggered CloneSpy's reaction.
As for the rest of our Game Boy run, CloneSpy mostly grouped variants of the same game together. There are some interesting findings, however, like a chunk of Tose games and a chunk from a potential mystery developer (see GDRI-009). See the full results here.