compressed with gzip. The typical file extension is .adz, derived from .adf.gz. IPF The ADF file format can only store disks that have legal AmigaDOS format tracks. Disks with non-standard tracks may be available in ADF format, albeit cracked in order to create a regular AmigaDOS volume. However, the Amiga itself was not limited to storing data in these standard tracks. The Amiga's floppy disk controller was very basic but transparent, and for that reason very flexible allowing disks of other and custom formats to be read and written as well. Disk handling is not locked down like the one in a modern PC, and so most of the work to read and write disks is done by the operating system itself. However, because programmers did not have to use the operating system routines, it was quite normal for games developers to create their own disk formats and also apply many different sorts of copy protection. As it was, most full-price commercial Amiga games had some form of custom disk format and/or copy protection on them. For this reason, most commercial Amiga games cannot be stored in ADF files unaltered, but there is an alternative called Interchangeable Preservation Format (IPF) which was specifically designed for this purpose. The Software Preservation Society Interchangeable Preservation Format (.IPF) is an open format for which the source code of the official library is available. DMS ADF files were sometimes compressed using the Disk Masher System, resulting in .dms files. FDI FDI (from Formatted Disk Image) is a universal disk image file format specification originally published by Vincent Joguin in 2000. The FDI format is publicly documented, and accompanied by open source access tools. Because the format can store raw low-level data, as is for example required to support copy protection schemes and other non-standard formats, FDI files can be larger than disk image files in other formats. The typical file extension is .fdi. Because of the universal design of the FDI format, files in other disk image formats, such as ADF, ADZ and DMS, can in theory be converted to FDI. See also References Notes The .ADF (Amiga Disk File) format FAQ The Amiga Guru Book, Chapter 15, Ralph Babel, 1993 Rom Kernel Reference Manual : Hardware, pages 235-244, Addison Wesley Rom Kernel Reference Manual : Libraries and Devices, Appendix C, Addison Wesley La Bible de l'Amiga, Dittrich/Gelfand/Schemmel, Data Becker, 1988. Disk images Amiga