Amiga 4000

Commodore Amiga 4000
Manufacturer Commodore
Type Personal computer
Release date 1992 (1992)
Discontinued 1994
Operating system AmigaOS 3.0
CPU Motorola 68EC030 or 68040 @ 25 MHz
Memory 2-18 MB
Predecessor Amiga 3000
Successor Amiga 4000T

The Commodore Amiga 4000, or A4000, is the successor of the A2000 and A3000 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 introduced the Advanced Graphics Architecture (AGA) chipset with enhanced graphics and continued the A3000's system architecture. However, the SCSI peripheral interface was replaced by the lower-cost IDE.

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.

Technical information

Processor and RAM

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.[1] There is a non-functional jumper that was intended to expand the Chip RAM to 8MB.[2] 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).

A4000-CR version

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 NiCd battery. The NiCd backup battery is one of the most common causes of problems in an aging A4000 because it has a tendency to eventually leak. The released fluids are somewhat corrosive and can eventually damage the motherboard.

Graphics and sound

The A4000 was the first Amiga model to ship with Commodore's third-generation Amiga chipset, the 32-bit Advanced Graphics Architecture (AGA). As the name implies, AGA introduced improved graphical abilities, specifically, a palette expanded from 12-bit color depth (4096 colors) to 24-bit (16.8 million colors) and new 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.

Peripherals and expansion

The A4000 has a number of Amiga compatible 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 interfaces, serial modems and sound samplers.[1]

Unlike early high-end Amiga models, the A4000 does not have an on-board DMA SCSI controller, instead a basic IDE controller was substituted. However, it is possible to add a SCSI controller as an expansion module.

Like the earlier Amiga 3000, the A4000 has four internal 32-bit Zorro III expansion slots. This expansion bus allows the use of devices which comply with the AutoConfig standard, such as, graphic cards, audio cards, network cards, SCSI controllers, and later even USB controllers.[3] 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 in 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 provided PCI slots allowing use of higher performance and widely available PCI hardware, such as, graphic, sound and network cards.

Operating System

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 A4000 compatible as 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.

Amiga 4000 with case open
Amiga A3200/A3400 CPU card

Specifications

Attribute Specification[1]
Processor Motorola 68EC030 or 68040 at 25 MHz
Bus speed 25 MHz
RAM 2-18 MB on board (2 MB "chip" RAM and up to 16 MB additional RAM);
Upgradable by further 128 MB via the CPU slot and 512 MB per Zorro III slot
ROM 512 kB Kickstart ROM
Chipset Advanced Graphics Architecture (AGA)
Video 24-bit color palette (16.8 Million colors)

Up to 256 on-screen colors in indexed mode
262,144 on-screen colors in HAM-8 mode
Resolutions from:

  • 320×200 to 1280×400i (NTSC)
  • 320×256 to 1280×512i (PAL)
  • 640×480 (VGA), 800×600i, 1024×768i[4]

Horizontal scan rates of 15.60-31.44 kHz
Vertical scan rates of 50–72 Hz

Audio 4 × 8-bit PCM channels (2 stereo channels)

28–56 kHz maximum DMA sampling rate (dependent on video mode in use)

Internal storage 120 MB 3.5" IDE hard disk drive (upgradable)
Removable storage 3.5" HD floppy disk drive (1.76 MB capacity)
Input/output ports Analog RGB video out (DB-23M)
Audio out (2 × RCA)
Keyboard (6 pin mini-DIN)
2 × Mouse/Gamepad ports (DE9)
RS-232 serial port (DB-25M)
Centronics style parallel port (DB-25F)
Floppy disk drive port (DB-23F)
Internal buffered ATA controller (40-pin)
Expansion slots 4 × 100pin 32-bit Zorro III slots
1 × AGA video slot (inline with Zorro slot)
3 × 16-bit ISA slots (requires bridgeboard to activate)
1 × 200-pin CPU expansion slot
4 or 5 × 72-pin SIMM slots
Operating system AmigaOS 3.0 (Kickstart 3.0/Workbench 3.0)
Physical dimensions W × H × D: 15 × 5 × 151⁄4" (380 × 125 × 395 mm)
Other 2 × front accessible 3.5" drive bays
1 × front accessible 5.25" drive bay
2 × internal 3.5" drive mountings
Key lock (disables mouse and keyboard)

See also

References

  1. 1 2 3 A4000 User's Guide (PDF), Commodore Electronics Limited, 1992
  2. ↑ "A4000 Motherboard Jumpers". Retrieved 2 September 2011.
  3. ↑ Haynie, Dave (20 March 1991), The Zorro III Bus Specification (PDF), Commodore-Amiga, Inc.
  4. ↑ HighGFX driver for ECS and AGA on Aminet
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