A file with .s00 extension is the first part of a compressed file that is split using the ZipSplitter software. Splitting the files into such smaller files reduces the overall size of the compressed archive and makes it easy for transportation over the internet. Remaining parts of the split archive are named with extensions .S01, .S02 and so on. When the file is supposed to be extracted, the .EXE file included with the split file is double-click. The EXE looks for .S00 file and uses the other accompanied files for extraction of the whole archive.
S00 File Format
S00 files are saved to disc as binary compressed archive. However, the internal file format details of S00 file format are not available publicly. Large files such as .WMV or .MP4 files are most often split using the ZipSplitter software to reduce their size.