- PS/2 answers with ERROR if PS/2 mouse is not connected,
  read_ack should handle error cases correctly. We should
  also probe correctly for the mouse. (0xFE on all commands)
- bochs shows us distorted text console output, why?
- bootloader has trouble detecting drive geometry of hard disks,
  only the floppy mode works reliably at the moment (in emulators
  and on real machines). Especially USB-pens in floppy BIOS emulation
  seems to report wrong CHS values.
- GUI: sort out a readable and type-safe (as much as possible)
  modus operandi. Accesses via base member chains are type safe, but
  we have to know the depth of the hierarchy of a derived class. Casts
  on the other hand are shorter to read, but not type-safe.
- real hardware like the Asus EEEPC 701 cannot switch A20 correctly,
  no clue why?
- if a task ends, what should we do? currently we crash
- memorymanagement should be a library of the libc or even a standalone
  library, not part of the kernel directory, get rid of kernel_panic
  there (this requires the kernel_stub.c kernel_panic to exist in
  libc tests)