The Bridgeboard card and the Janus library made the use of PC expansion cards and harddisk/floppydisk drives possible. Bridgeboard cards appeared up to 486 processor variants. Later the Sidecar was implemented on an expansion card named ' Bridgeboard' for Amiga 2000+ models. At the introduction of the Sidecar the crowd was stunned to see the MS-DOS version of Microsoft Flight Simulator running at full speed in an Amiga window on the Workbench. Clever programming (a library named Janus, after the two-faced Roman god of doorways) made it possible to run PC software in an Amiga window without use of emulation. In order to run the MS-DOS operating system, Commodore released the Sidecar for the Amiga 1000, basically an 8088 board in a closed case that connected to the side of the Amiga. MS-DOS compatibility was a major issue during the early years of the Amiga's lifespan in order to promote the machine as a serious business machine. MS-DOS on Amiga via Sidecar or Bridgeboard 1 MS-DOS on Amiga via Sidecar or Bridgeboard.
