QDOS is an Operatingsystem designed for small 68000 computers,
    which provides multitasking, a virtual device interface for grafics,
    an easy to program device driver interface, and last, but not least
    a highly sophisticated structured and expandable resident command
    language interpreter called "SuperBASIC". Since it was first
    implemented on a computer with only 128K RAM and 48K ROM this
    operating system and its supporting Software and compilers are
    small and very efficient, mostly programmed directly in native
    68000 machinecode. This makes QDOS the ultimate operating system
    for all small computers like for example the Amiga 500 and single
    board controller computers, which can use a  real time operating
    system and the whole support software for their applications.
    QDOS was written by Tony Tebby, who has my deep respect for this.