text: Hi,
  > > I just found a bug in the floppy driver. Andy disabled the support for
  > > the second floppy driver. Unfortunately there is a bug that then
  > > results in random writes into the memory.
  >
  > Hmmm. Is this a bug in the standard driver, or is this my fault?
  It is a bug in the standard driver that was activated by your changes.
  Just look into drivers/block/floppy.c, into function set_fdc(). This
  functions calls set_dor() twice. Once for controller fdc and once
  for controller 1-fdc. The later call results in erroneous memory
  accesses when N_FDC (in <asm/floppy.h>) has been defined to 1, not two.
  Just put #if N_FDC > 1 ... #endif around the second call and everything
  is ok.
  Finding this bug was a bit of luck - I wondered about certain "unplaned"
  memory accesses when debugging something else. The consequences however
  are fatal - every process that is just running when set_fdc is being
  called gets "tuned" ...
  Ralf