ROM Hacking - Distribution

Distribution

Once a hack is completed (or an incomplete version is deemed suitable for an interim release) it is released onto the Internet for others to play. The generally accepted way to do this is by making a patch (in IPS format or others) that can be applied to the unmodified ROM. This, and usually some form of documentation, is put in an archive file and uploaded somewhere. IPS is a format for recording the differences between two binary files (in this case, between the unmodified and hacked ROMs) and is suitable for ROM hacks. IPS is still used today for small patches—however, as ROMs became larger in size, this format became useless, leading to quite a few file formats being created—such as NINJA and PPF ("PlayStation Patch Format"). PPF is still used today, particularly to patch large files such as ISO CD images and Nintendo 64 games. A new patch format, UPS, has also been developed by the ROM hacking community, designed to be the successor to IPS and PPF. A more recent patching format, the APS patching system, has also been developed by a devoted Game Boy Advance ROM hacker. The APS system is more space efficient, reversible, and is faster than its predecessor.

The purpose of distributing a hack in patch form is to avoid the legal aspects of distributing entire ROM images; the patch records only what has changed in the ROM, hence distributing it does not distribute parts of the original game. A patch is also smaller than the full ROM image (an NES ROM can run anywhere from 8KB-2MB; a Super NES ROM can run from 256k-6MB). The use of patches does not eliminate copyright issues because the patches may be considered derivative works; however, corporations generally ignore them as long as they are not distributed with the ROMs.