The T64 file format is a tape image format used primarily for archiving Commodore 64 software. It's a container format that stores the contents of a Commodore 64 cassette tape, including program code, data, and other information. Unlike some other C64 archive formats (like D64 for disk images), T64 files are designed to represent the sequential nature of data stored on cassette tapes. This means the data is stored in the order it would be read from the tape. T64 files are commonly used by Commodore 64 enthusiasts and emulators to preserve and distribute classic C64 games and applications. They offer a convenient way to store and load software without needing the original physical tapes. The format typically includes header information that describes the contents of the tape, such as program names and load addresses. Emulators use this information to accurately simulate the loading process of the original Commodore 64. While not as versatile as disk images for some purposes, T64 files are essential for preserving the authentic experience of using cassette-based software on the C64.