Often from the PlayStation (PSX), Sega Saturn, or early PC era.

The "cd" prefix typically denotes a compact disc image, while the numerical string "1213" is an internal ID or sequence number used by archivists to track thousands of individual discs. The .7z extension indicates that the file was compressed using , a high-ratio compression format preferred by preservationists to save space when storing large "ISO" or "BIN/CUE" disc images. What is usually inside?

The use of the .7z format for files like "cd1213.7z" is intentional for several reasons: