Commodore A2286 AT Bridgeboard
The Commodore A2286 AT Bridgeboard is basically a PC-AT on a card, meant to
be used in any of the 'big box' Amiga's such as the A2000, A3000, or A4000.
It is a Zorro-II board which acts as a 'bridge' between the Zorro slots in
the Amiga and the ISA slots inline with them, and in fact the A2286 actually
plugs into both slots. With the bridgeboard installed it is possible to
utilize ISA expansion cards, including video, from within the PC software
running on the bridgeboard's cpu. It contains an 80286 cpu running at 8mhz,
an onboard floppy controller, 1024k of RAM, PC-AT compatible BIOS, and an
optional 80287 math coprocessor socket. The Bridgeboard emulates the PC-XT
keyboard using the Amiga's keyboard and the PC's parallel port using the
Amiga's parallel port, as well as IBM PC MDA or CGA graphics if there is no
ISA video card installed. The onboard floppy controller is capable of
supporting both 5.25" and 3.5" floppy drives in both low and high density
formats, and in fact the A2286 normally shipped with a 1.2meg high density
5.25" drive. There were also bridgeboards made which had either an 8088 or
80386SX cpu. All of the Commodore Bridgeboard's shipped with Janus library
software, which provided the interface between the Amiga user and the 80x86
cpu, version 2.1 being the latest.
Interestingly, since the bridgeboards enable the use of the ISA slots inline
with the Zorro slots in 'big box' Amiga's, there have been a number of
drivers written which allow the use of certain ISA cards from the Amiga side
as well, such as networking cards.
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