The Amiga is a family of personal computers introduced by Commodore in 1985. The original model was one of a number of 16/32- and 32-bit computers that featured 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio over 8-bit systems. This wave included the Atari ST—released the same year—Apple's Macintosh, and later the Apple IIGS. Based on the Motorola 68000 microprocessor, the Amiga differed from its contemporaries through the inclusion of custom hardware to accelerate graphics and sound, including sprites and a blitter, and a pre-emptive multitasking operating system called AmigaOS.
The Amiga 1000 was released in July 1985, but a series of production problems kept it from becoming widely available until early 1986. The best selling model, the Amiga 500, introduced in 1987 (along with the more expandable / professional oriented Amiga 2000) became one of the leading home computers of the late 1980s and early 1990s with four to six million sold. The A3000 was introduced in 1990, followed by the A500+, and the A600 in March 1992. Finally, the A1200 and the A4000 were released in late 1992. The platform became particularly popular for gaming and programming demos. It also found a prominent role in the desktop video, video production, and show control business, leading to video editing systems such as the Video Toaster. The Amiga's native ability to simultaneously play back multiple digital sound samples made it a popular platform for early tracker music software. The relatively powerful processor and ability to access several megabytes of memory enabled the development of 3D rendering packages, including LightWave 3D, Imagine, Aladdin4D, TurboSilver and Traces, a predecessor to Blender.
Although early Commodore advertisements attempt to cast the computer as an all-purpose business machine, especially when outfitted with the Amiga Sidecar PC compatibility add-on, the Amiga was most commercially successful as a home computer, with a wide range of games and creative software. Poor marketing and the failure of the later models to repeat the technological advances of the first systems meant that the Amiga quickly lost its market share to competing platforms, such as the fourth generation game consoles, Macintosh, and the rapidly dropping prices of IBM PC compatibles, which gained 256-color VGA graphics in 1987. Commodore ultimately went bankrupt in April 1994 after a version of the Amiga packaged as a game console, the Amiga CD32, failed in the marketplace.
Since the demise of Commodore, various groups have marketed successors to the original Amiga line, including Genesi, Eyetech, ACube Systems Srl and A-EON Technology. Likewise, AmigaOS has influenced replacements, clones and compatible systems such as MorphOS, AmigaOS 4 and AROS. (Full article...)
In computing, a rigid disk block (RDB) is the block on a hard disk where the Amiga series of computers store the disk's partition and filesystem information. The PC equivalent of the Amiga's RDB is the master boot record (MBR).
Unlike its PC equivalent, the RDB doesn't directly contain metadata for each partition. Instead it points to a linked list of partition blocks, which contain the actual partition data. The partition data includes the start, length, filesystem, boot priority, buffer memory type and "flavor", though the latter was never used. Because there is no limitation in partition block count, there is no need to distinguish primary and extended types and all partitions are equal in stature and architecture.
Additionally, it may point to additional filesystem drivers, allowing the Amiga to boot from filesystems not directly supported by the ROM, such as PFS or SFS. (Full article...)