Everything You Always Wanted To Know
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Amiga Technical References

The Bridgeboard is a full length Zorro II card that will let your Amiga 2000/3000(T)/4000(T) computer system run MS-DOS and Windows compatible software. There have been three different models of Bridgeboards made.

This was the first Bridgeboard made. It is based off the Intel 8088 CPU, which is an 8-bit version of the 8086 CPU found in most XT compatible computers. Fully compatible with the 8086 it will run any software for the XT class of machines. The A8088 bridgeboard came standard with a 4.77mhz CPU, 512K of RAM, Monochrome/CGA display and a 360K 5.25" disk drive.

This was the second Bridgeboard that was made. It is based off the Intel 20286 chip found in any AT compatible computer system. It came standard with an 8mhz CPU, 1mb of RAM, Monochrome/CGA display and a 1.2mb 5.25" disk drive.

This was the last Bridgeboard made. There are three versions of it, all are based off the 80386SX chip. This chip differs in that it is internally a 32-bit chip, but it only has a 16-bit bus (like the 68000). All A2386SX Bridgeboards came standard with a 16mhz/20mhz/25mhz CPU, 1mb of RAM (up to 8mb on board), Monochrome/CGA graphics, and they could use your Amiga 3.5" disk drive.

Janus versions

All Bridgeboards use a library system called Janus to handle communication between the host Amiga computer and the Bridgeboard itself. The latest version of Janus is version 2.1 which only came standard with the A2386SX Bridgeboard. Janus 2.1 will work with the A2088 and A2286 Bridgeboards. Features in Janus 2.1 over v2.0 are:

• Windows 3.x compatible display and mouse drivers.
• New ARead and AWrite utilities, more options and wildcard support.
• Autoload feature which will start up the Amiga side service when the PC requests it (AMouse, ATime, etc).
• Install utility that will set-up hardfiles, install enforcer, etc.
• Workbench 2.0 compliant interface.

Compatibility problems / Bridgeboard Problems

The best way to think of the Bridgeboard is as an IBM on a card stuck in your Amiga. The only parts of the IBM that are being emulated are the keyboard, mouse, hard drive, and display. Even for some of these they can be replaced by the real thing. For example its possible to install a Microsoft mouse, or a I/O card with a real hard drive or a VGA card. Despite all of that, I'm sure that you will probably find some software or hardware that doesn't like the Bridgeboard. I have listed these below, along with any way to fix the problem (if there is a fix).

• DosShell turns to garbage when I select a graphics display. This is a fault of the AMouse driver. You must either run DosShell in a text display or use a real Microsoft compatible mouse.
• The AMouse driver doesn't operate with program "#####". The AMouse driver isn't that great under DOS, your only fix for this is to install a real Microsoft compatible mouse on the Bridgeboard.
• How do I install the AMouse3.drv in Windows? The AMouse3.drv (comes with Janus 2.1), will operate under Windows 3.0 and 3.1, however you have to install it manually. First install Windows, then enter your Windows directory and edit the file called "SYSTEM.INI". Find the line called "mouse.drv=#####" and set it to "mouse.drv=amouse3.drv". Lastly, put a copy of the AMouse3.drv in the "system" directory found in your "windows" directory.
• My hardfiles don't work. Most common problem is that you have an 68030/040 CPU. With these CPUs you need to either
  1. Turn the CPU DataCache off or
  2. Install the Enforcer utility (if your CPU has an MMU)
• Always getting a message that Janus.library cannot be found. This could be caused by a couple of different things.
  1. You don't have the "binddrivers" statement in your startup-sequence.
  2. You don't have the "Janus.library" in the Expansion drawer on your boot drive.
  3. You have all 8 megabytes of autoconfig RAM used up (can only have 6 megabytes of autoconfig RAM)
• My hardfile access is very slow. If you increase the buffers on the hard drive that has the hard file on it your access time will improve. You need to add A LOT of buffers to make it faster (like 800 to 1000 buffers). Also, hardfile speed is based on the size of the hardfile, a large hardfile is slower than a smaller one. (Check out Janus Tools for partition support).

Bridgeboard Utilities

Here are a few programs that will make life using your Bridgeboard a bit easier.

My FTP server only allows 36 anonymous users on at one time, so if you get a refuse message, try again in a few minutes.

Janus 2.1: Here is the Janus 2.1 software, placed here as a courtesy to users who's disks that have gone bad or for users who purchased a used Bridgeboard that didn't come with the Janus software. (283K Amiga / 102K PC)

AmiCDex: This program will let you use a CD-Rom drive that is connected to your Amiga on your Bridgeboard. This way, you don't have to get a SCSI card or a second CD-Rom drive for your Bridgeboard. (91K FTP)

Bridgeboard CPU Upgrade: This contains information about upgrading A2386SX Bridgeboards with different 486 clip-on modules. (362K FTP)

Janus Tools: This package contains two different utilities. The first one, is a replacement interface for A2386SX Bridgeboards with a VGA card. It lets you access all the different features of Janus from one interface, and will even run a auto-switch box (if you build one). The second utility is the great one, it will let you use an Amiga hard drive partition as a PC hard drive. It is much faster than a hard file and easy to set up as well. This partition utility will run with any Bridgeboard, as long as you have Janus v2.1. (44K FTP)

Copyright © 2000 Amiga Auckland Inc. All rights reserved.
Revised: June 16, 2005.