Amiga 4000: Обзор и характеристики компьютера 1992 года

1992 personal computer

The Amiga 4000, or A4000, from Commodore is the successor of the Amiga 2000 and Amiga 3000 computers. There are two models: the A4000/040 released in October 1992 with a Motorola 68040 CPU, and the A4000/030 released in April 1993 with a Motorola 68EC030. The Amiga 4000 system design was generally similar to that of the A3000, but introduced the Advanced Graphics Architecture (AGA) chipset with enhanced graphics. The SCSI system from previous Amigas was replaced by the lower cost Parallel ATA. The original A4000 is housed in a beige horizontal desktop box with a separate keyboard. Later, Commodore released an expanded tower version called the A4000T. The machine is reported to have sold 11,300 units in Germany.

The stock A4000 shipped with either a Motorola 68EC030 or 68040 CPU, 2 MB of Amiga Chip RAM and up to 16 MB of additional RAM in 32 bit SIMMs. There is a non functional jumper that was intended to expand the "chip RAM" to 8MB. Later, third party developers created various CPU expansion boards featuring higher rated 68040, 68060 and PowerPC CPUs. Such hardware also typically offers faster and higher capacity RAM (128 MB or greater).

Unlike previous Amiga models, early A4000 machines have the CPU mounted in an expansion board; the motherboard does not have an integrated CPU. Later revisions of the A4000 have the CPU and 2 MB RAM surface mounted on the motherboard in an effort to reduce costs. These machines are known as the A4000 CR (cost reduced) and the surface mounted CPU is a 68EC030. The cost reduced models also make use of a non rechargeable lithium battery for real time clock battery backup rather than a rechargeable NiCad battery. The NiCad backup battery is one of the most common causes of problems in an aging device that uses one because it has a tendency to eventually leak. The released fluids are somewhat corrosive and can eventually damage the circuitry.

The A4000 is the first Amiga model to have shipped with Commodore's third generation Amiga chipset, the 32 bit Advanced Graphics Architecture (AGA). As the name implies, AGA introduces improved graphical abilities, specifically, a palette expanded from 12 bit color depth (4,096 colors) to 24 bit (16.8 million colors) and new 64, 128, 256 and 262,144 (HAM 8) color modes. Unlike earlier Amiga chipsets, all color modes are available at all display resolutions. AGA also improves sprite capacity and graphics performance. The on board sound hardware remains identical to that of the original Amiga chipset (the Paula sound chip), namely, four DMA driven 8 bit PCM channels, with two channels for the left speaker and two for the right.

The A4000 has a number of Amiga specific connectors, including two DE 9 ports for joysticks, mice, and light pens, a standard 25 pin RS 232 serial port and a 25 pin Centronics parallel port. As a result, at launch the A4000 was compatible with many existing Amiga peripherals, such as MIDI devices, serial modems and sound samplers. One of the most notable hardware items of the era is the NewTek Video Toaster system which became popular in the 1990s for amateur and commercial desktop video production of standard definition broadcast quality video, consisting of tools for video switching, chroma keying, character generation, animation, and image manipulation. The three ISA slots can be activated by use of a bridgeboard, which connects the Zorro and ISA buses. Such bridgeboards typically feature on board IBM PC compatible hardware, including Intel 80286, 80386, or 80486 microprocessors allowing emulation of an entire IBM PC system in hardware. Compatible ISA cards may then be installed into the two remaining ISA slots. Later, in an effort to offer modern expansion options third party developers created replacement expansion boards for the A4000 which provide PCI slots allowing use of higher performance and widely available PCI hardware, such as graphic, sound, and network cards.

The A4000 shipped with AmigaOS 3.0, consisting of Workbench 3.0 and Kickstart 3.0, which together provide a single user multi tasking operating system and support for the built in hardware. Following release of AmigaOS 3.1 it became possible to upgrade the A4000 by installing compatible Kickstart 3.1 ROM chips. The later AmigaOS 3.5 and 3.9 releases were software only updates requiring Kickstart 3.1. AmigaOS 4, a PowerPC native release of the operating system, can be used with the A4000 provided a CyberStorm PPC board is installed. Likewise, MorphOS, an alternative Amiga compatible operating system, can be used with this hardware. Variants of platform independent operating systems, such as Linux and BSD, can also be used with the A4000.

Digital Domain used an Amiga 4000 for motion control effects in films such as True Lies, Apollo 13, and Titanic.