For other uses see Amiga (disambiguation).
The Amiga is a family of personal computers originally developed by Amiga Corporation. Development on the Amiga began in 1982 with Jay Miner as the principal hardware designer. Commodore International bought Amiga Corporation and introduced the machine to the market in 1985. The name Amiga was chosen by the developers specifically from the Spanish and Portuguese word for a female friend, and because it occurred before Apple and Atari alphabetically.
Based on the Motorola 68k series of microprocessors, the machine sports a custom chipset with then advanced graphics and sound capabilities, and a pre-emptive multitasking operating system (now known as AmigaOS). While the M68k is a 32-bit processor, the version originally used in the Amiga, the 68000, has a 16-bit external data bus so it must transfer 32 bits of data in two consecutive steps, a technique called multiplexing -- all this is transparent to the software, which was 32-bit from the beginning. The original machine was generally referred to in the press as a 16-bit computer; later models sported fully 32-bit designs. The Amiga provided a significant upgrade from 8-bit computers such as the Commodore 64, and the Amiga quickly grew in popularity among computer enthusiasts, especially in Europe, and sold approximately 6 million units.
It also found a prominent role in the desktop video / video production and show control business, and was a less expensive alternative to the Apple Macintosh and IBM-PC. The Amiga was most commercially successful as a home computer, although early Commodore advertisements attempted to place the Amiga into several different markets at the same time. 
Since the demise of Commodore, various groups have marketed successors to the original Amiga line. Eyetech sold Amiga hardware under the AmigaOne brand from 2002 to 2005.
See main article: History of the Amiga. The Amiga was originally designed by a small company called Amiga Corporation, and initially intended to be a next generation video game machine, but was later redesigned into a general purpose computer.  Before the machine was released into the market the company was purchased by Commodore. The first model was released in 1985 as simply "The Amiga from Commodore", later to be retroactively dubbed the Amiga 1000. The following year the Amiga product line was expanded with the introduction of two new models; the Amiga 2000 for high-end graphics and business use, and the Amiga 500 was for home use. Commodore later released several new Amiga models, both for low-end gaming use and high-end productivity use. Throughout the 1980s, the Amiga's combination of hardware and operating system software offered great value, but by the mid-nineties other platforms, most successfully the PC running Microsoft Windows, reduced this advantage.
In 1994, Commodore filed for bankruptcy and its assets were purchased by Escom, a German PC manufacturer, who created the subsidiary company Amiga Technologies. They re-released the A1200 and A4000T, and introduced a new 68060 version of the A4000T.
However, Escom in turn went bankrupt in 1997. The Amiga brand was then sold to another PC manufacturer, Gateway 2000, which had announced grand plans for it. However, in 2000, Gateway sold the Amiga brand without releasing a product.
The current owner of the trademark, Amiga, Inc., licensed the rights to make hardware using the Amiga brand to a UK computer vendor, Eyetech Group, Ltd, which was founded by some former UK employees of Commodore International. They were previously selling the AmigaOne via an international dealer network. The AmigaOne is a PowerPC computer designed to run the latest version of AmigaOS, which was itself licensed to a Belgian-German company, Hyperion Entertainment.
At its core, the Amiga features custom designed coprocessors, used for handling tasks such as audio, video, encoding and animation. This freed up the Amiga's central processor for other tasks (given that the coprocessors could keep up with the central processor's demands) and gave the Amiga an edge on its competitors in many situations.
The platform also introduced other innovations. The Amiga CDTV, for example, was the first computer to feature a CD-ROM drive as standard, as well as being one of the earlier computers to no longer include a floppy drive in the standard configuration. The Amiga was also one of the first computers for which inexpensive sound sampling and video digitization accessories were available.
Although it was once regarded as "unemulatable," since around 2000, many different platforms have Amiga emulation programs available that reproduce the Amiga's hardware functions in software. This allows users to run Amiga software without the need for an actual Amiga computer.
All Commodore Amiga models make use of Motorola Central Processing Units (CPUs) based on the Motorola 68k architecture. In desktop-style Amiga models, the CPU was fitted on a daughterboard (except the A2000) called a CPU card. Low-cost Amiga models come with CPUs either socketed or soldered onto the motherboard. On all Amiga models the CPU can be upgraded through an expansion card or direct CPU replacement. CPU cards were provided by both Commodore and third-party manufacturers. These cards often come with on-board memory slots and hard drive interfaces, alleviating those tasks from the base Amiga.
The Amiga is not limited to solely the 68k CPU architecture; although Commodore never shipped one, it is possible to install a PowerPC coprocessor that can be used by PowerPC-aware software and libraries, and later the AmigaOne used a PowerPC CPU instead of a 68k CPU.
There are three generations of chipsets used in the various Amiga models. The first is the OCS, followed by the ECS and finally the AGA. What all these chipsets have in common is that they handle raster graphics, digital audio and communication between various peripherals (e.g., CPU, memory and floppy disks) in the Amiga.
All Amiga systems can display full-screen animated graphics with 32, 64 (EHB Mode) or 4096 colors (HAM Mode). Models with the AGA chipset (A1200 and A4000) also have 128, 256 and 262,144 (HAM Mode) color modes and a palette expanded from 4096 to 16.8 million colors.The Amiga chipset can genlock — adjust its own screen refresh timing to match an NTSC or PAL video signal. When combined with setting transparency, this allows an Amiga to overlay an external video source with graphics. This ability made the Amiga popular for many applications, and provides the ability to do character generation and CGI effects far more cheaply than earlier systems. Some frequent users of this ability included wedding videographers, TV stations and their weather forecasting divisions (for weather graphics and radar), advertising channels, music video production, and 'desktop video'. The NewTek Video Toaster was made possible by the genlock ability of the Amiga.
The sound chip, named Paula, supports four sound channels (two for the left speaker and two for the right) with 8-bit resolution for each channel and a 6-bit volume control per channel. The analog output is connected to a low-pass filter, which filters out high-frequency aliases when the Amiga is using a lower sampling rate (see Nyquist limit). The brightness of the Amiga's power LED is used to indicate the status of the Amiga’s low-pass filter. The filter is active when the LED is at normal brightness, and deactivated when dimmed (or off on older A500 Amigas). On Amiga 1000, the power LED had no relation to the filter's status, a wire needed to be manually soldered between pins on the sound chip to disable the filter. Paula can read directly from the system's RAM, using direct memory access (DMA), making sound playback without CPU intervention possible.
Although the hardware is limited to four separate sound channels, software such as OctaMED uses software mixing to allow eight or more virtual channels, and it was possible for software to mix two hardware channels to achieve a single 14-bit resolution channel by playing with the volumes of the channels in such a way that one of the source channels contributes the most significant bits and the other the least ones.
The quality of the Amiga's sound output, and the fact that the hardware is ubiquitous and easily addressed by software, were standout features of Amiga hardware unavailable on PC platforms for years. Third-party sound cards exist that provide DSP functions, multi-track direct-to-disk recording, multiple hardware sound channels and 16-bit and beyond resolutions. A retargetable sound API called AHI was developed allowing these cards to be used transparently by the OS and software.
The classic Amiga Operating System consists of Kickstart (including System API) and Workbench. In the Amiga 1000 model, Kickstart is first loaded from a floppy disk, followed by Workbench, or other bootable disk. Later models hold Kickstart (and system API) on a ROM, improving start-up times. Models can be upgraded by changing the ROM.
The ROMs are generally known as "Kickstart" and start with version 1.0 (A1000 floppy) and end with Kickstart 3.1. There are hardware and software packages that can "shadow" Kickstart into memory. This resulted in faster operation for functions dependent on the ROM, at the cost of system memory to store the ROM data.
Many expansion boards were produced for Amiga computers to improve the performance and capability of the hardware, such as memory expansions, SCSI controllers, CPU boards, and graphics boards. Other upgrades include genlocks, ethernet cards, modems, sound cards and samplers, video digitizers, USB cards, extra serial ports, and IDE controllers.
The most popular upgrades were memory, SCSI controllers and CPU accelerator cards. These were sometimes combined into the one device, particularly on big-box Amigas like the A2000, A3000 and A4000.
Early CPU accelerator cards feature full 32-bit CPUs of the 68000 family such as the Motorola 68020 and Motorola 68030, almost always with 32-bit memory and usually with FPUs and MMUs or the facility to add them. Later designs feature the Motorola 68040 and Motorola 68060. Both CPUs feature integrated FPUs and MMUs. Many CPU accelerator cards also had integrated SCSI controllers.
Phase5 designed the PowerUp boards (BlizzardPPC and CyberstormPPC) featuring both a 68k (a 68040 or 68060) and a PPC (603 or 604) CPU, which are able to run the two CPUs at the same time (and share the system memory). The PPC CPU on PowerUp boards is usually used as a coprocessor for heavy computations (a powerful CPU is needed to run for example MAME, but even decoding JPEG pictures and MP3 audio was considered heavy computation in those years). It is also possible to ignore the 68k CPU and run Linux on the PPC (project Linux APUS), but a PPC-native Amiga OS was not available when the PPC boards first appeared.
24-bit graphics cards and video cards were also available. Graphics cards are designed primarily for 2D artwork production, workstation use, and later, gaming. Video cards are designed for inputting and outputting video signals, and processing and manipulating video.
Perhaps the most famous video card in the North American market was the NewTek Video Toaster. This was a powerful video effects board which turned the Amiga into an affordable video processing computer which found its way into many professional video environments. Due to its NTSC-only design it did not find a market in countries that used the PAL standard, such as in Europe. In PAL countries the OpalVision card was popular, although less featured and supported than the Video Toaster. Low-cost time base correctors (TBCs) specifically designed to work with the Toaster quickly came to market, most of which were designed as standard Amiga bus cards.
Various manufacturers started producing PCI busboards for the A1200 and A4000, allowing standard Amiga computers to use PCI cards such as Voodoo graphic cards, Sound Blaster sound cards, 10/100 ethernet cards, and TV tuner cards.
PowerPC upgrades with Wide SCSI controllers, PCI busboards with ethernet, sound and 3D graphics cards, and tower cases allowed the A1200 and A4000 to survive well into the late nineties.
Expansion boards were made by Richmond Sound Design that allow their show control and sound design software to communicate with their custom hardware frames either by ribbon cable or fiber optic cable for long distances, allowing the Amiga to control up to eight million digitally controlled external audio, lighting, automation, relay and voltage control channels spread around a large theme park, for example. See Amiga software for more information on these applications.
See main article: Amiga models and variants. The "classic Amiga" models were produced from 1985 to 1996. They are, in order of appearance: 1000, 2000, 500, 1500, 2500, 3000, 3000UX, 500+, 3000T, CDTV, 600, 4000, 1200, CD32, and 4000T. The PowerPC based AmigaOne was later produced from 2002 to 2005. Some companies have also released Amiga clones.
The Amiga 500 was Commodore’s best-selling Amiga model. Early units, at least, had the words "B52/ROCK LOBSTER" silk-screen printed onto their printed circuit board, a reference to the popular song "Rock Lobster" by the rock band The B-52's. Commodore's two subsequent console style models also carried a reference to the same band on their motherboards - the Amiga 600 had "JUNE BUG" (after the song "Junebug") and the Amiga 1200 had "CHANNEL Z" (after "Channel Z").
Commodore released three significant upgrades: the Amiga 2000 in 1987, the Amiga 3000 in 1990, and the Amiga 4000 in 1992. These upgrades improved the platform's graphical abilities, allowing for more colors and different display modes, and added expansion slots and ports. The best selling models, however, were the much cheaper but still versatile console models - the Amiga 500 (1987) and the Amiga 1200 (1992).
See main article: AmigaOS 4.
AmigaOS 4 is designed for PowerPC Amiga systems and currently runs on both Amigas equipped with CyberstormPPC or BlizzardPPC accelerator boards, and on the PPC Teron series based AmigaOne computers built by Eyetech under license by Amiga Inc. AmigaOS 4.0 had been available only in developer pre-releases for numerous years until the final update was 'released' in December 2006. Due to the nature of some provisions of the contract between Amiga Inc. and Hyperion Entertainment the Belgian-German firm which is developing the OS, the commercial AmigaOS had only been available licensed to buyers of AmigaOne motherboards.
AmigaOS 4.0 for Classic Amigas equipped with PPC (Cyberstorm PPC or BlizzardPPC) accelerator boards was released commercially in November 2007, prior to this it was available only to developers and beta-testers. The most recent release AmigaOS is 4.1.
No new hardware has been released since the AmigaOne; however Acube Systems has entered into an agreement with Hyperion under which it has ported AmigaOS 4 to its SAM440 line of PowerPC-based motherboards.
Long-time Amiga developer MacroSystem entered the Amiga-clone market with their DraCo nonlinear video edit system. It appears in two versions, initially a tower model and later a cube. DraCo expanded upon and combined a number of earlier expansion cards developed for Amiga (VLabMotion, Toccata, WarpEngine, RetinaIII) into a true Amiga-clone powered by Motorola's 68060 processor. The DraCo can run AmigaOS 3.1 up through AmigaOS 3.9. It is the only Amiga-based system to support FireWire for video I/O. DraCo also offers an Amiga-compatible ZORRO-II expansion bus and introduced a faster custom DraCoBus, capable of 30 MB/sec transfer rates (faster than Commodore's ZORRO-III). The technology was later used in the Casablanca system, a set-top-box also designed for non-linear video editing.
In 1998, Index Information released the Access, an Amiga-clone similar to the A1200, but on a motherboard which could fit into a standard 5 1/4" drive bay. It features either a 68020 or 68030 CPU, with a redesigned AGA chipset, and runs AmigaOS 3.1.
In 2006, two new Amiga-clones were announced. The Minimig is a personal project of Dutch engineer Dennis van Weeren. Minimig replicates the Amiga OCS custom chipset inside an FPGA. The original model was built on a Xilinx Spartan 3 development board, but now a dedicated board has been demonstrated. The design for Minimig was released as Open Source on July 25, 2007. In December, 2007, an Italian company Acube Systems announced plans to commercially produce the original Minimig. In February 2008 Acube began selling Minimig boards.
Individual Computers has announced development of the Clone-A system. As of mid 2007 it has been shown in its development form, with FPGA-based boards replacing the custom chips in an Amiga 500.
See main article: AmigaOS. At the time of release AmigaOS put an OS that was well ahead of its time into the hands of the average consumer. It was the first commercially available consumer operating system for personal computers to implement preemptive multitasking . Other features included combining a graphical user interface with a command-line interface, allowing long filenames permitting whitespace and not requiring a file extension and the use of information files associated with other files to store icons, launch and other desktop data.
John C. Dvorak stated in 1996 that AmigaOS "remains one of the great operating systems of the past 20 years, incorporating a small kernel and tremendous multitasking capabilities the likes of which have only recently been developed in OS/2 and Windows NT. The biggest difference is that the AmigaOS could operate fully and multitask in as little as of address space."
Like other operating systems of the time, the OS lacks memory protection. This is necessary also because the 68000 CPU of the first Amiga computers does not include a memory management unit, and because there is no way of enforcing use of flags indicating memory to be shared. Although it speeds and eases interapplication communication (programs can communicate by simply passing a pointer back and forth), the lack of memory protection made the Amiga OS more vulnerable to crashes from badly behaving programs, and fundamentally incapable of enforcing any form of security model since any program had full access to the system. Later this memory protection feature was implemented in AmigaOS 4.
The problem was somewhat exacerbated by Commodore's initial decision to release documentation relating not only to the OS's underlying software routines, but also to the hardware itself, enabling intrepid programmers who cut their teeth on the Commodore 64 to POKE the hardware directly, as was done on the older platform. While the decision to release the documentation was a popular one and allowed the creation of fast, sophisticated sound and graphics routines in games and demos, it also contributed to system instability as some programmers lacked the expertise to program at this level. For this reason, when the new AGA chipset was released, Commodore declined to release documentation for it, forcing most programmers to adopt the approved software routines.
Commodore-Amiga produced Amiga Unix, informally known as Amix, based on AT&T SVR4. It supports the Amiga 2500 and Amiga 3000 and was included with the Amiga 3000UX. Among other unusual features of Amix is a hardware-accelerated windowing system which can scroll windows without copying data. Amix is not supported on the later Amiga systems based on 68040 or 68060 processors.
Other, still maintained, operating systems are available for the classic Amiga platform, including Linux and NetBSD. Both require a CPU with MMU such as the 68020 with 68851 or full versions of the 68030, 68040 or 68060. There is also a version of Linux for Amigas with PowerPC accelerator cards. Debian and Yellow Dog Linux can run on the AmigaOne.
See main article: Emulation on the Amiga. The Amiga is able to emulate other computer platforms ranging from many 8-bit systems such as the Sinclair ZX Spectrum, Commodore 64, Nintendo Game Boy, Nintendo Entertainment System, Apple II and the TRS-80, up to platforms such as the IBM PC, Apple Macintosh and Atari ST. MAME (the arcade machine emulator) is also available for Amiga systems with PPC accelerator card upgrades.
See main article: Amiga software. The Amiga was a primary target for productivity and game development during the late 1980s and early 1990s. Software was often developed for the Amiga and the Atari ST simultaneously, since the ST shared a similar architecture.
Aminet was created in 1992 and until around 1996, was the largest public archive of software for any platform.
When an Amiga is reset, the Kickstart code selects a boot device (floppy or hard drive), loads the first two sectors of the disk or partition (the bootblock), and passes control to it. Normally this code passes control back to the OS, continuing to boot from the device or partition it was loaded from. The first production Amiga, the Amiga 1000, needed to load Kickstart from floppy disk into 256 kilobytes of RAM reserved for this purpose, but subsequent Amigas held Kickstart in ROM. Some games and demos for the A1000 (notably Dragon's Lair) provided an alternative code-base in order to use the extra 256 kilobytes of RAM for data.
A floppy disk or hard drive partition bootblock normally contains code to load the 'dos.library' (AmigaDOS) and then exit to it, invoking the GUI. Any such disk, no matter what the other contents of the disk, was referred to as a "Boot disk", "bootable disk" or "Workbench disk". (A bootblock could be added to a disk by use of the "install" command.)Some entertainment software contains custom bootblocks. The game or demo then takes control of memory and resources to suit itself, effectively disabling AmigaOS and the Amiga GUI.
The bootblock became an obvious target for virus writers. Some games or demos that used a custom bootblock would not work if infected with a bootblock virus, as the code of the virus replaced the original. The first such virus was the SCA virus. Anti-virus attempts included custom bootblocks. These amended bootblock advertised the presence of the virus checker while checking the system for tell-tale signs of memory resident viruses and then passed control back to the system. Unfortunately these could not be used on disks that already relied on a custom bootblock, but did alert users of potential trouble. Several of them also replicated themselves across other disks, becoming little more than viruses in their own right.
The Boing Ball has been synonymous with Amiga since its public release in 1985. It has been a popular theme in computer demo effects since the 1950s, when a bouncing ball demo was released for Whirlwind computers. Commodore released a bouncing ball demo at the 1978 Consumer Electronics Show, to illustrate the capabilities of the VIC chip. A similar theme was used to demonstrate the capabilities of the Amiga computer at the 1984 Consumer Electronics Show. It was a real-time animation showing a red-and-white balloon bouncing forth and back off the edges of the screen, as a deep 'boing!' sound played on each impact. Since then, the Boing Ball became one of the most well-known symbols for Amiga and compatible computers. Within the context of this tradition of bouncing ball demos at the Consumer Electronics Show, CBS Electronics also showed a Bouncing Ball demo for the Atari VCS/2600, with a spinning and bouncing ball, at the same event.
The 1984 Boing Ball demo was one of the very first demos shown on the Amiga. It was specifically designed to take advantage of the Amiga's custom graphics and sound hardware, achieving a level of speed and smoothness not previously seen on a home computer. This demo operated in an Intuition Screen, allowing the higher resolution Amiga Workbench screen to be dragged down to make the Boing Ball visible from behind, bouncing up above the Workbench while the Workbench remained fully active. Since the Boing Ball used almost no CPU time, this made a particularly impressive demonstration of multitasking at the time.
Despite its popularity in the Amiga community, the Boing Ball itself was never officially adopted as a trademark by Commodore. The official Amiga trademark was a rainbow-colored double checkmark. After the bankruptcy of Commodore, the Boing Ball remained in use as one of the symbols for Amiga-related systems on hundreds of web sites and products by different companies and individuals.
The demo was once ported to the Atari 2600 under the title Boing. The porter impressed himself so much that he added a little Easter Egg, which he referred to as lame (When you hold down the game reset switch, the checkered ball turns into a message that says HAPPY XMAS 1999!-----FROM ROB KUDLA and Jingle Bells starts playing. You also won't hear the bounce sound effect. Releasing the switch stops the music, turns the message back into the checkered ball, and the boing sound effect is played again when the ball bounces).
When Commodore went bankrupt in 1994, there was still a very active Amiga community, and it continued to support the platform long after mainstream commercial vendors abandoned it. The most popular Amiga magazine, Amiga Format, continued to publish editions until 2000, some six years after Commodore filed for bankruptcy. Another magazine, Amiga Active, was launched in 1999 and was published until 2001. Interest in the platform is high enough to sustain a specialist column in the UK weekly magazine Micro Mart.
As of December 2008, there was enough demand for Amiga expansion hardware to keep some small-scale manufacturers in business.
The Amiga series of computers found a place in early computer graphic design and television presentation. Below are some examples of notable uses and users:
In addition, many other celebrities and notable individuals have made use of the Amiga: