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Filename extensions | .adf, .adz |
---|---|
Internet media type | application/x-amiga-disk-format |
Magic number | DOS |
Container for | disk data |
Amiga Disk File (ADF) is a file format used by Amiga computers and emulators to store images of floppy disks. It has been around almost as long as the Amiga itself, although it was not initially called by any particular name. Before it was known as ADF, it was used in commercial game production, backup and disk virtualization. ADF is a track-by-track dump of the disk data as read by the Amiga operating system, and so the "format" is really fixed-width AmigaDOS data tracks appended one after another and held in a file. This file would, typically, be formatted, like the disk, in Amiga Old File System (OFS).
Most ADF files are plain images of the Amiga-formatted tracks held on cylinder 0 to 79 of a standard 3.5-inch (89 mm) double-density floppy disk, also called an 880 KiB disk in Amiga terms. The size of an ADF will vary depending on how many tracks have been imaged, but in practice it is unusual to find ADF files that are not 901,120 bytes in size (80 cylinders × 2 heads × 11 sectors × 512 bytes/sector).
Most Amiga programs were distributed on double-density floppy disks. There are also 3.5-inch high-density floppy disks, which hold up to 1.76 MB of data, but these are uncommon. The Amiga also had 5.25-inch double-density disks. The WinUAE Amiga emulator supports all three disk formats, but 3.5-inch double-density is the most common.
ADF files can be downloaded and copied to Amiga disks with the EasyADF application and various applications freely available on the Internet. As they are plain disk images, they can be handled by the Unix tool dd
. On Linux and NetBSD, which support the most common Amiga filesystems, ADF files can be mounted directly.
There is a program called ADF Opus, which is a Microsoft Windows –based program that allows people to create their own ADF files. This program supports creating double density (880 KB ADF files, the most common) and high-density (1.76 MB) ADF files. ADF Opus also allows people to convert ADF files into ADZ files.
There is also a GPL command line program called unADF, which allows you to extract files from an ADF file.
The part of utility pack amitools contains a set of programs named xdftool. It is under GPL and can read, write, format, and do other operations with ADF-images.
An ADZ file is an ADF file that has been compressed with gzip. The typical file extension is .adz
, derived from .adf.gz
.[ citation needed ]
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.[ citation needed ] 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. [1] 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 [2] and also apply many different sorts of copy protection. [3] 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. [4]
ADF files were sometimes compressed using the Disk Masher System, resulting in .dms files.
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, [5] 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.
A floppy disk or floppy diskette is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a fabric that removes dust particles from the spinning disk. The three most popular floppy disks are the 8-inch, 5¼-inch, and 3½-inch floppy disks. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device.
Optical disc authoring, including CD, DVD, and Blu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical disc. This act is sometimes done illegally, by pirating copyrighted material without permission from the original artists.
The Amiga Fast File System is a file system used on the Amiga personal computer. The previous Amiga filesystem was never given a specific name and known originally simply as "DOS" or AmigaDOS. Upon the release of FFS, the original filesystem became known as Amiga Old File System (OFS). OFS, which was primarily designed for use with floppy disks, had been proving slow to keep up with hard drives of the era. FFS was designed as a full replacement for the original Amiga filesystem. FFS differs from its predecessor mainly in the removal of redundant information. Data blocks contain nothing but data, allowing the filesystem to manage the transfer of large chunks of data directly from the host adapter to the final destination.
On the Amiga, the Old File System was the filesystem for AmigaOS before the Amiga Fast File System. Even though it used 512-byte blocks, it reserved the first small portion of each block for metadata, leaving an actual data block capacity of 488 bytes per block. It wasn't very suitable for anything except floppy disks, and it was soon replaced.
Atari DOS is the disk operating system used with the Atari 8-bit computers. Operating system extensions loaded into memory were required in order for an Atari computer to manage files stored on a disk drive. These extensions to the operating system added the disk handler and other file management features.
WHDLoad is a software package for the Amiga platform to make installation of software to a hard disk easier, for such things as demos or games. Allowing for better compatibility for Amiga software, which can sometimes have hardware incompatibilities making them hard to use in emulated environments due to the widely varying hardware specifications of the Amiga product line across its history. WHDLoad basically circumvents the operating system in the Amiga for greater compatibility and preserves the original program environment.
The Disc Filing System (DFS) is a computer file system developed by Acorn Computers, initially as an add-on to the Eurocard-based Acorn System 2.
Floppy disk format and density refer to the logical and physical layout of data stored on a floppy disk. Since their introduction, there have been many popular and rare floppy disk types, densities, and formats used in computing, leading to much confusion over their differences. In the early 2000s, most floppy disk types and formats became obsolete, leaving the 3+1⁄2-inch disk, using an IBM PC compatible format of 1440 KB, as the only remaining popular format.
Distribution Media Format (DMF) is a format for floppy disks that Microsoft used to distribute software. It allowed the disk to contain 1680 KiB of data on a 31⁄2-inch disk, instead of the standard 1440 KiB. As a side effect, utilities had to specially support the format in order to read and write the disks, which made copying of products distributed on this medium more difficult. An Apple Macintosh computer running Disk Copy 6.3.3 on the Mac OS 7.6 or later operating system can copy and make DMF disks. The first Microsoft software product that uses DMF for distribution were the "c" revisions of Office 4.x. It also was the first software product to use CAB files, then called "Diamond".
A floppy-disk controller (FDC) is a hardware component that directs and controls reading from and writing to a computer's floppy disk drive (FDD). It has evolved from a discrete set of components on one or more circuit boards to a special-purpose integrated circuit or a component thereof. An FDC is responsible for reading data presented from the host computer and converting it to the drive's on-disk format using one of a number of encoding schemes, like FM encoding or MFM encoding, and reading those formats and returning it to its original binary values.
CrossDOS is a file system handler for accessing FAT formatted media on Amiga computers. It was bundled with AmigaOS 2.1 and later. Its function was to allow working with disks formatted for PCs and Atari STs. In the 1990s it became a commonly used method of file exchange between Amiga systems and other platforms.
IMG, in computing, refers to binary files with the .img
filename extension that store raw disk images of floppy disks, hard drives, and optical discs or a bitmap image – .img
.
Amiga software is computer software engineered to run on the Amiga personal computer. Amiga software covers many applications, including productivity, digital art, games, commercial, freeware and hobbyist products. The market was active in the late 1980s and early 1990s but then dwindled. Most Amiga products were originally created directly for the Amiga computer, and were not ported from other platforms.
The Disk Masher System (.dms) is an often used method on the Amiga, to create a compressed image of a disk. The disk is read block-by-block, and thus its data structure is maintained. DMS won approval particularly in the demo scene and the Warez scene, since with this tool, disk images could generally be transferred easily with telecommunication modems to mailbox networks like FidoNet for efficient distribution.
Amiga support and maintenance software performs service functions such as formatting media for a specific filesystem, diagnosing failures that occur on formatted media, data recovery after media failure, and installation of new software for the Amiga family of personal computers—as opposed to application software, which performs business, education, and recreation functions.
A floppy disk is a disk storage medium composed of a thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD). Floppy disks were an almost universal data format from the 1970s into the 1990s, used for primary data storage as well as for backup and data transfers between computers.
Amiga Forever is an Amiga preservation, emulation and support package published by Cloanto, allowing Amiga software to run on non-Amiga hardware legally without complex configuration.
The Advanced Disc Filing System (ADFS) is a computing file system unique to the Acorn computer range and RISC OS-based successors. Initially based on the rare Acorn Winchester Filing System, it was renamed to the Advanced Disc Filing System when support for floppy discs was added and on later 32-bit systems a variant of a PC-style floppy controller.
The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk.
KryoFlux is a hardware and software solution for preserving software on floppy disks. It was developed by the Software Preservation Society.