<b>KC-CAOS 4.4</b>, upgraded operating system of the East German home computer <b><a href="https://en.wikipedia.org/wiki/KC_85" class="extiw" title="en:KC 85">KC 85/4</a></b>, manufactured by the <a href="https://en.wikipedia.org/wiki/Kombinat_Mikroelektronik_Erfurt" class="extiw" title="en:Kombinat Mikroelektronik Erfurt">VEB Mikroelektronik</a> "Wilhelm Pieck" Mühlhausen, 1988. It is displayed on a <a href="https://en.wikipedia.org/wiki/Colormat" class="extiw" title="en:Colormat">RFT Colormat</a> television set.
Guido Grohmann, Zerbst/Anhalt (Germany)
Attribution
The author sent the photo to me.