Retrobrad - For Retro Gamers!

The A1000, or Commodore Amiga 1000, was Commodore's initial Amiga personal computer, introduced on July 24, 1985 at the Lincoln Center in New York, USA. Machines began shipping in September with a base configuration of 256KB of RAM at the retail price of US$1,295. A 13-inch analog RGB monitor was available for around US$300 bringing the price of a complete Amiga system to $1,595. Before the release of the Amiga 500 and A2000 models in 1987, the A1000 was simply called Amiga.

The A1000 had a number of characteristics that distinguished it from later Amigas: It was the only model to feature the short-lived Amiga "checkmark" logo on its case; the case was elevated slightly to give a storage area for the keyboard when not in use (a "keyboard garage"); and the inside of the case was engraved with the signatures of the Amiga designers, including Jay Miner and the paw print of his dog Mitchy.

Because AmigaOS was rather buggy at the time of the A1000's release, the OS was not placed in ROM. Instead, the A1000 included a daughterboard with 256 KiB of RAM, dubbed the "Writable Control Store" (WCS), into which the operating system was booted from floppy disk (the disk containing the 256 KiB image was called "Kickstart"). The WCS was write-protected after loading, and system resets did not require a reload of the WCS. In Europe the WCS was often referred to as WOM (Write Once Memory) as opposite to ROM (Read Only Memory).

Many A1000 owners remained attached to their machines long after newer models rendered the units technically obsolete, and it attracted numerous aftermarket upgrades. Many CPU upgrades that plugged into the Motorola 68000 socket functioned in the A1000. Additionally, a line of products called the Rejuvinator series allowed the use of newer chipsets in the A1000, and an Australian-designed replacement A1000 motherboard called The Phoenix utilized the same chipset as the A3000 and added an A2000-compatible video slot and onboard SCSI.

CPU: Motorola 68000 (7.16 MHz NTSC, 7.09 MHz PAL)

Chipset: OCS (Original Chipset)

Audio (Paula): 4 voices / 2 channels (Stereo) 8-bit resolution / 6-bit volume 28 kHz sampling rate 70 dB S/N Ratio

Video (Common resolutions): 320×200 with 32 colors or HAM-6
320×400i with 32 colors or HAM-6 640×200 with 16 colors 640×400i with 16 colors

Memory: 8 Kk ROM for bootstrap code. 256 Kb of Chip RAM by default, with an additional 256 Kb provided by a dedicated cartridge. Practical upper limit of about 9 Mb of Fast RAM memory due to being limited to an 24-bit address bus. This memory can not be utilized by the chipset, and is therefore faster.

Removable Storage: 3.5" DD Floppy drive, capacity 880 Kb

Input/Output connections: Composite TV out (PAL versions sold in Europe and Australia, NTSC elsewhere) Analogue RGB video plug
RCA audio plugs 2 × Game/Joy ports (used by the mouse) Keyboard port RS232 Serial port (DB25) Centronics Parallel port (DB25) Port for external floppy drive One expansion port for add-ons (memory, SCSI adaptor, etc), electrically identical to the Amiga 500 expansion port.
Resources handled by AutoConfig

Software (Bundled): AmigaOS 1.0/1.1/1.2 operation system, loaded from the Kickstart floppy disk at power-on. Microsoft Amiga BASIC
Voice synthesis library

The Amiga 1000 had a 7.15909 MHz 68000 CPU (7.09 MHz for PAL machines). This is precisely double the 3.58 MHz NTSC color carrier frequency, and was needed by the Amiga chipset when outputting NTSC video. All frequencies in the Amiga 1000 are derived from this frequency as it simplified glue logic and allowed the Amiga 1000 to make do with a single cheap mass-produced crystal.

Though most users attach an analog RGB monitor and most units even were sold together with an A1080/1/2 RGB-Monitor, the A1000 also has a built-in composite video output which allow the computer to be connected directly to a TV or VCR. However, the output signal is considered too "hot" (strong) by many to be useful for anything other than home use. This can be remedied by running the A1000's composite output through a video processing amplifier, or "proc amp", to bring the video levels down to a suitable level.

It is possible to do a direct socket replacement of the standard 7 MHz 68000 CPU with a 68010 CPU. The 68010 executes instructions slightly faster than the 68000, but the conversion also introduces a small degree of software incompatibility.