A GDI dump is a raw, uncompressed, and unaltered image of the original GD-ROM. It typically consists of a small .gdi text file (a track manifest) and several .bin or .raw files containing the actual data and audio tracks. Because it mirrors the original disc's structure perfectly, it offers the highest compatibility with modern emulators (like Flycast or Redream) and Optical Drive Emulators (ODEs) like the GDEMU.
If you love the Sega Dreamcast, you owe it to yourself to abandon the compressed, choppy CDI files of the early 2000s. The format represents the highest fidelity available to emulation fans. dreamcast roms gdi