<b>Z 9001-OS</b>, standard operating system of the East German home computer <b><a href="https://en.wikipedia.org/wiki/Robotron_KC_87" class="extiw" title="en:Robotron KC 87">Robotron KC 85/1</a></b> and its successor KC 87, manufactured by the <a href="https://en.wikipedia.org/wiki/Robotron" class="extiw" title="en:Robotron">VEB Robotron</a>-Meßelektronik "Otto Schön" Dresden. It is displayed on a Russian Junost television set.
Hans Wollny
Attribution
The author sent the photo to me.