The HP 16700 series logic analyzers ran HP-UX. There were scope cards for this logic analyzer. Also before that the HP 16505A prototype analyzer, which was used together with the 16500-series logic analyzer. The later 16900 series ran Windows.
It wouldn't surprise me if some of the high-end HP scopes, like sampling mainframes, ran HP-UX in the 90s, but I'm not familiar with those.