A G64 file is a disk image format specifically designed for Commodore 64 (C64) emulation. Unlike the more common D64 format, which stores sector-by-sector data, the G64 format captures the raw Group Coded Recording (GCR) data stream directly from a Commodore 1541 floppy disk drive. This means it records the magnetic flux transitions as they appear on the physical disk, rather than just the decoded logical data. This capability makes G64 files particularly valuable for preserving and emulating C64 software that utilizes sophisticated copy protection schemes or non-standard track layouts, which often rely on precise timing and low-level disk access that D64 files cannot replicate. While G64 files are typically larger than their D64 counterparts for the same disk, they offer a higher degree of authenticity and compatibility with original hardware behavior. Emulators use G64 files to simulate the 1541 drive's operations at a very low level, providing an accurate experience for many commercial C64 games and applications that were otherwise difficult or impossible to run from standard disk images. It is an essential format for preservationists and enthusiasts seeking the most faithful emulation of Commodore 64 disk-based software.