The OSKit includes code that understands the various partitioning schemes used to divide disk drives into smaller pieces for use by filesystems. This code enables the use of various (possibly nested) partitioning schemes in an easy manner without requiring knowledge of which partitioning scheme was used, or how these partitioning schemes work. E.g., you don't need to understand or know the format of a VTOC to use the partitioning, as the library does all of it for you.