 In most cases the nibbler software still analyses the data on a byte level, only looking to the bit level when dealing with synchronization marks (syncs), zero-gaps and other sector & track headers.When possible, nibblers will work with the low-level data encoding format used by the disk system, being "Group Coded Recording" (GCR - Apple, Commodore), "Frequency Modulation" (FM - Atari), or "Modified Frequency Modulation" (MFM - Amiga, Atari, IBM PC).Software piracy began to be a problem when floppy disks became the common storage media.