Eyetech Group Ltd

The AmigaOne 1200 & 4000, the Predator, GRex and Mediator boards - A factual clarification of similarities and differences

For immediate release

This brief note is to highlight the differences in these product lines by outlining the basic specifications of the Predator, G-Rex and AmigaOne 1200/4000 products and how their design philosophy differs both from each other and from the Mediator board from Elbox.

Finally please note that we continue to refuse to get drawn into any unprofessional and public arguments with Elbox over their reaction to any products which are even vaguely competitive to their Mediator design. There are however some misleading inaccuracies in their press release of 30 October 2000 which this note will also help clear up.
 

The AmigaOne 1200 & 4000 are 6xPCI + 1xAGP stand-alone G3/G4 boards capable of running the Amiga DE directly (which is being ported to the design by Amiga Inc). These boards are designed to fit in the most popular A1200/A4000 tower systems, and optionally connect to the A1200/A4000 motherboard for access to Classic Amiga chipset hardware. In this mode the AmigaOne 1200/4000 can also be used to run the Classic Amiga OS & software with a very high degree of compatibility - because it has access to all the Classic Amiga custom chips.

It is however of fundamental importance to note that the A1200/A4000 'computer' now resides on the AmigaOne board - having direct high-speed access to all the AmigaOne's PCI/AGP peripherals, and only accessing the existing A1200/A4000 chipset (via the A1200 edge connector or the A4000 cpu connector) as and when required. Any existing 680x0 or PPC accelerator is entirely redundant, its function being carried out by the AmigaOne's G3/G4 cpu & memory. For this reason the provision of a pass-through accelerator slot on either the A1200 or A4000 version of the AmigaOne is completely pointless. In our view a small cardboard box provides much more cost-effective storage for an unused accelerator card than an expensive edge connector.

For entirely hardware independent (retargetable) applications the AmigaOne 1200/4000 hardware is capable of running them without an A1200 or A4000 motherboard being attached at all.
 
 

The Predator and GRex boards (which are of similar - but not identical - design) add PCI (& AGP in the case of the Predator-Plus) facilities to an Amiga 1200 or 4000 with a phase5/DCE design of PPC (or Cyberstorm Mk3) accelerator. These boards use the local bus (BVision/CyberVisionPPC) connector on the phase5 accelerator to give a high speed interface between cpu and PCI/AGP slots, and use other logic on the accelerator to interface to the Amiga motherboard's onboard chipset & peripherals.

Using this local bus allows full linear addressing of the PCI/AGP cards within the cpu's address space, and allows busmastering and DMA to be implemented not just between PCI/AGP cards but between the cards and the accelerator card's onboard memory. This design does not require the use of any paging registers for data transfer between cpu and PCI board, and removes any contention between the lower speed A1200 edge connector bus (which is used exclusively for accessing the Amiga's onboard peripherals and chipset resources) and the high speed local bus (which is used exclusively for PCI/AGP access).

In addition the Predator-Plus also has provision for an on-board G3/G4 cpu and SDRAM memory to provide a user-installable PPC accelerator uprade.

Unlike the AmigaOne 1200/4000 the Predator and GRex boards need an A1200/A4000 motherboard and appropriate BizzardPPC/CyberstormPPC/Cyberstorm Mk3 accelerator installed to function.

The Mediator board from Elbox, was, in our understanding, originally designed to be a PCI-only replacement for the Zorro II-based Z4 busboard from Apollo, primarily to allow the use of low cost PCI graphics cards in an A1200. The Elbox design uses a bespoke paged memory mapper to allow compatibility with all A1200 accelerators (providing they are fast enough to drive the graphics card) and transfers all data - both to the PCI and Amiga's on board peripherals/chipset resources - over the A1200 edge connector bus. For its intended (non Amiga DE, non-G3/G4, non-Amiga DE-compatible) A1200 upgrade market this is certainly a workable option.

Since the Eyetech's original Predator announcement in September 2000 Elbox have announced a variety of add-on/upgrade cards for the Mediator, presumably to provide it with superficially similar facilities to those embodied in the design of the Predator. However - as we understand it - these upgrades will still rely on (paged) cpu and memory access from the existing Amiga accelerator over the A1200 edge connector.

Elbox have also recently announced an A4000 version of the Mediator which, we understand, basically uses the same technology as the A1200 version but physically connects via the Zorro bus using the 8MB Zorro II address space for a paged PCI memory interface.

We hope this helps clear up the differences between these three significant upgrade products for Classic Amiga computers.