BRIDGEBOARDS AND THE SIDECAR. 
                      by Michael Burbury 

   ARE THEY WORTH IT? 

   Think about it for a little.  You can now purchase a complete IBM
   system for less than a complete BridgeBoard kit.

   All the IBM emulators use interrupt level 3 (INT3) for communication
   between the IBM and Amiga.  This is a major downfall with compatibility
   of programs that were written in Pascal or use INT3.  Do not try to use
   Pascal on a BridgeBoard as the whole system will freeze.  Also do not
   try to use IBM Network cards as they use INT3 as well.  Modem software
   can also cause system freezes when exiting.  Compatibility with most
   other software and games seems to be good but it does have it limits as
   well as being incredibly slow.
     
   
   THE SIDECAR: 

   Standard it comes with 256K of memory and one 5.25" drive.  The speed
   is only 4.77Mhz but with the addition of a 8087 math co-processor it
   chuggs along at a better rate.  The screen updating through the Amiga
   is too slow for playing your favorite flight simulator and is not very
   smooth.  After running several bench mark tests it performed much the
   same as the old Commodore PC5 with limitations on the graphics
   capabilities.  It can be suited to the Amiga 500 and Hard Drives with
   an IBM controller can be used.  This is its main advantage to someone
   who wants both IBM and Hard Drives for their Amiga.  I personally would
   suggest using a combination of both Janus release versions of software
   for optimum usage (ie Janus 2.20 Libraries and Janus 2.63 Utilities and
   System).  You may contact Commodore at any time for the updated Janus
   software (ask for Software Support).
   
   THE XT BRIDGEBOARD: 
   The KIT comes with one 5.25" floppy drive, XT BridgeBoard, Cable,
   mounting screws, manuals (too brief yet again), and Janus 2.20
   software.  The XT BridgeBoard comes standard with 512K of memory.  If
   you own a Subsystem or an Amiga 2000 Model "A" do not try to use the
   latest BridgeBoard as it will not work.  See if you can get an older
   one using BIOS ROMs Version 4 or less.  The newer one was made to
   interface with the Buster IC which is not in the Amiga 500 Subsystem or
   the Amiga 2000 Model "A".  The A2058 Memory expansion has the same
   features and has difficulties running on the A2000 Model "A".
   
   THE AT BRIDGEBOARD: 

   The KIT comes with one 5.25" high density floppy drive, AT
   BridgeBoard, Cable, mounting screws, manuals (still very brief), and
   Janus 2.63 software.  The AT BridgeBoard come standard with 1 Megabyte
   of memory.  The same applies with the AT as with the XT but early
   revisions will not work on the systems above either. It was
   specifically made for the A2000 Model "B".

   Speed can be increased by addition of a 80287 math co-processor but is
   still not that much faster than the XT BridgeBoard.  Combined
   floppy/hard cards can be used but can also cause excessive hair pulling
   when they don't work.  The AST RAMPAGE card really makes the difference
   if you are going to use ZENIX System 5 and the performance increases
   dramatically including the interfacing with the Amiga.  It will
   auto-boot from a partition on the A2090A controller's hard drive but
   data transfer is extremely slow (ie about the same rate as the floppy).
   It is best to save files compressed to alleviate this problem.


   The Amiga will format and transfer files in IBM format on its standard
   3.5" floppy drive so the need for IBM compatibility actually inside
   your Amiga is reduced.  The tasks needed to run a bridgeboard are
   lengthy and time consuming for the Amiga's processor thus slowing the
   system down.  If you are in the market for a BridgeBoard seriously
   think about a complete IBM system as it will run on your 1084 monitor
   anyway.