Amiga

Commodore's 1985 follow-on to the Commodore 64, the Amiga was one of the first true "multimedia PCs", and featured several technologies that were years ahead of their time (including the 16/32-bit central processor). Executive Meddling and Misaimed Marketing kept the system from selling well in the USA, but elsewhere, the Amiga was far more popular and has a cult following to this day. (And when we say "cult", we mean it-Amigans are far more faithful to their platform than Macintosh fans, which is saying something after all it's been through.) At the time, its primary competition was the Atari ST.

The Amiga's heart was a set of extremely powerful custom integrated circuits designed by Jay Miner, who was also responsible for the custom graphics chips in the Atari 2600 and Atari 8 Bit Computers. These chips had names like "Fat Agnes" and included functions such as a "blitter", which allowed fast screen updates, and a "copper" that implemented scanline DMA (which eventually became a common trick on 16-bit consoles). The Amiga also included 4-channel, DMA-driven audio, which led to the development of the first MOD trackers, and the Demoscene that surrounded them. Amiga could also "genlock" to NTSC or PAL video, making it very popular with TV production facilities; NewTek developed the Video Toaster, an early 3D animation system, to work with the Amiga's genlock and overlay capabilities. Many TV shows in the late 1980s and early 1990s used Amigas for computer screens and special effects, notably The Chart Show and Babylon 5. The development of anime fansubs in the late 1980s is also tied to the Amiga and its genlock capabilities, as it represented the first method of overlaying subtitles on video without high-end equipment unaffordable to the average user.

On top of this was AmigaOS, an operating system that had one of the earliest implementations of preemptive multitasking on a consumer PC (though without memory protection) and a relatively friendly GUI called "Workbench". The A1000 even had multiple desktops, which provided prior art that defeated a patent troll.

Commodore eventually failed in 1994, and the Amiga, supported by fans, moved from company to company until settling down in 2000. AmigaOS was ported to the PowerPC and was sold on new hardware called the AmigaOne for a time in the early 2000s. AmigaOne is now planning to sell a new computer, the AmigaOne X1000

The revived Commodore USA is also planning to release modernized versions of the Amiga 1000, 2000, and 3000 (with Intel CPUs, so they can run Microsoft Windows as well as Commodore's own OS).

Original Chip Set (OCS) Amigas, 1985-91

 * A1000 (1985): 68000 CPU, Workbench 1.0-1.3
 * A500 (1987): Lower-cost and improved version of the A1000, Workbench 1.2-3.1
 * A2000 (1987): High-end model based on the A500, with expansion slots and drive bays
 * A2000HD (1988): With a hard drive
 * A2500 (1989): With a 68020 or 68030 accelerator card, 32-bit Fast RAM, hard drive, and possibly a 'flickerfixer' card for VGA output.
 * A2500UX (1990): Similar to the A2500, but with the A2410 graphics card, and bundled with AMIX, the Amiga port of Unix.
 * CDTV (1991): Multimedia appliance based on the A500.

Enhanced Chip Set (ECS) Amigas, 1990-92

 * A3000 (1990): 68030 CPU, Workbench 2.04-3.9
 * A3000UX (1990): A3000 with AMIX
 * A3000T (1991): Tower model with more slots and bays
 * Late A2000 (1991): 68000 CPU, Workbench 2.04-3.1
 * A500+ (1991): 68000, Workbench 2.04-3.1
 * A600 (1992): 68000, Workbench 2.1-3.1

Advanced Graphics Architecture (AGA) Amigas, 1992-94

 * A1200 (1992): 68EC020 CPU, Workbench 3.0-3.9
 * A4000 (1992): High-end model, 68030 or 68040 CPU
 * CD32 (1993): Videogame console based on the A1200
 * A4000T (1994): Tower A4000 with more slots and bays, final Commodore Amiga

Post-Commodore Amigas

 * AmigaOne (2002): PowerPC G4 CPU, off the shelf graphics, Workbench 4
 * AmigaOne X1000 (201?): PWRficient PA6T CPU, Workbench 4.1

Other machines compatible with AmigaOS 4

 * Genesi Pegasos II (2004): PowerPC G4 CPU, AmigaOS 4 ported to it in 2009
 * ACube Sam440ep and Sam440ep-flex (2008): PowerPC 440 CPU
 * ACube Sam460ex (2010): PowerPC 440 CPU

Processors

 * CPU: Motorola 680x0 series (Commodore era) or PowerPC (post-Commodore)
 * GPU, OCS and ECS: "Agnus" (coprocessor/blitter) and "Denise" (sprites, video display)
 * GPU, AGA: "Alice" (coprocessor/blitter) and "Lisa" (video display)
 * Sound: "Paula"

Memory

 * The Amiga was notorious for its split RAM banks, called "Chip RAM" and "Fast RAM". Chip RAM (graphics memory shared with the CPU) was used by Agnus/Alice and had to run at lock-step with the vertical refresh. Fast RAM (CPU-only system memory) could be accessed by the CPU at full speed. Then there was Slow RAM, the worst of both worlds.
 * OCS Amigas had 256K (A1000), 512K (A500, A2000), or 1MB (late A2000, CDTV) Chip RAM, 512K Slow RAM (A500 via internal REU, A2000) and up to 8MB Fast RAM.
 * ECS Amigas had 1-2MB Chip RAM, up to 8MB (A500+, A600) or more (A3000) Fast RAM
 * AGA Amigas had 2MB Chip RAM, up to 16MB (A1200) or more (A4000) Fast RAM

Display: OCS/ECS

 * 4096 color palette
 * Nominal resolution from 320x200 to 640x400 NTSC, 320x256 to 640x512 PAL
 * Overscan up to 736x482 NTSC, 736x576 PAL
 * ECS: 1280x400 with 4 colors out of 64
 * 32 independent colors in 320xX, plus an "Extra Half-Brite" mode that adds 32 more colors, half as bright as the first 32
 * 16 colors in 640xX
 * Hold And Modify mode in 320xX: all 4096 colors on screen
 * Palette swaps on scanline interrupt
 * 16 hardware sprites
 * Coprocessor and blitter for hardware scrolling and sprite manipulation

Display: AGA

 * 16 million color palette
 * All OCS/ECS resolutions, plus 640x480, 800x600 and 1024x768
 * 256 colors at any resolution
 * HAM-8 mode with 262,144 colors on screen

Sound

 * Four DMA-driven eight-bit PCM channels, software mixable into two fourteen-bit PCM. For a time in the late 1980s and early 1990s, the Amiga was as good as it got when it came to sample-based sound, unless you had the money to buy a professional sampler/workstation.

Notes for those who might want to buy hardware:
Apart from the CD32, the main game-playing Amigas are the 500 and the 1200. Most A500 games will run on both, though for older or badly made titles, a piece of software called relokick may be required. In the early days, game developers were encouraged to bypass the OS and access the hardware directly, optimizing performance at the expense of forwards compatibility. The 'correct' '80s Amiga is an A500 with the OCS and Workbench 1.2 or 1.3. You will also need some more RAM, preferably the A501 512k "trapdoor" card.

The A501 Slow RAM expansion for the A500, and the A500+, A2000, A3000, and A4000 have a NiCd battery to back up the clock. With age, these batteries leak acid onto the motherboard, ruining it. If you're interested in an Amiga on Ebay, demand to see a picture of the battery before you buy it.

There's also Amiga Forever, which is a collection (sold either as an ISO9660 image or a physical CD) containing system ROM images and OS disk images for all Commodore-era hardware and OS versions (that is, up to 3.1), for use in an emulator (such as WinUAE, E-UAE, or UAE).

Killer Apps, exclusive titles, and Multi Platform games that started here:

 * Agony
 * Alien Breed
 * Another World
 * Apidya
 * Arcticfox
 * Battle Chess
 * Beneath a Steel Sky
 * Cannon Fodder
 * Carrier Command
 * The Chaos Engine
 * Dark Seed
 * Defender of the Crown
 * Elvira: Mistress of the Dark]]
 * Elvira II: The Jaws of Cerberus
 * F/A-18 Interceptor
 * Fire and Ice
 * Flashback
 * Flight Of The Amazon Queen
 * Formula One Grand Prix aka World Circuit
 * Frontier: Elite II
 * Gods
 * Hired Guns
 * It Came From The Desert
 * The Killing Game Show
 * Knights of the Sky
 * Lemmings
 * Lemmings 2: The Tribes
 * Mind Walker
 * The Secret of Monkey Island
 * The Sentinel
 * Pinball Dreams
 * Pinball Fantasies
 * Pipe Mania
 * Populous
 * Red Storm Rising
 * Renegade Legion
 * Rings of Medusa
 * Sensible Soccer
 * Shadow of the Beast
 * Sim City
 * Simon the Sorcerer
 * Skidmarks
 * Star Control
 * Starglider
 * Stunt Car Racer
 * SWIV
 * Sword of Sodan
 * Syndicate
 * Test Drive
 * Theme Park
 * The Town With No Name
 * Walker
 * Wax Works
 * Wing Commander
 * Wizkid
 * Worms
 * Zeewolf
 * Zool

Ports:

 * Aladdin
 * The Bards Tale Trilogy
 * Bubble Bobble
 * Defender
 * Desert Strike
 * Dune II
 * Exile (1988 action game; not that Exile)
 * Falcon
 * Head Over Heels
 * Indianapolis 500: The Simulation
 * The Lion King
 * Might and Magic II (OCS) and III (AGA)
 * The New Zealand Story
 * Pang
 * Parasol Stars
 * Pit-Fighter
 * Puggsy
 * Qwak
 * Rainbow Islands
 * Rod Land
 * The Secret of Monkey Island
 * Monkey Island 2 Le Chucks Revenge
 * The Curse of Monkey Island
 * Sid Meiers Pirates (OCS) and Pirates! Gold (AGA)
 * Snow Bros (not officially released)
 * Space Harrier
 * Space Harrier: Return to the Fantasy Zone
 * Space Harrier II
 * Stunts aka 4D Sports Driving
 * Tetris
 * Total Carnage
 * Turrican
 * Vigilante
 * Zaxxon

Magazines

 * Amiga Power