Holger Veit wrote:
  Problem is of course that the Elektor OSI computer
uses a rather
 obscure floppy controller and formatting (some GCR emitted by an
 asynchronous 6850 that is hacked into a synchronous mode). 
It's FM, not GCR.
Of course, it's not IBM-standard FM.  Normally it can
only be read and written on an OSI (or Elektor) system.  Given how
expensive FDC chips were when OSI designed their floppy controller, I
suppose it can be considered a clever hack, though nowhere near as
clever as Woz's design for the Disk II controller.