SunOS 4.0.3 desktop from 1989. I will take this over modern stuff any day. Sun was rock solid with Unix and hardware stuff until Oracle decided to ruin that iconic brand.
A fine system indeed.
Is this the PostScript-based window system?
I forget if it ran on SunOS 4.0.
If not, then it ought to be X11.
Doesn't look like SunView.