Eyetech Group Ltd
Phone:
+44 164 271 3185 : 07000 4 AMIGA : 07000 426 442 : 01642 713
185
Fax: +44 164 271 3634 : 01642 713 634
The AmigaOne 1200 & 4000, the Predator, GRex and Mediator
boards - A factual clarification of similarities and
differences
For immediate release
We believe that all of the above products - including the Mediator
- represent very worthwhile expansion options for Classic Amiga
users. However each of the above products has been designed to give
the Classic Amiga user specific and quite different expansion and
forward progression capabilities, and it is therefore important to
note that these different product lines are not functionally
interchangeable and the type selected should be carefully chosen
with regard to the Amiga's current and intended future use.
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.
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