The design of Ops incorporates ideas that were considered but dropped for The Bridge on [Star Trek: The Next Generation], such as the upper level office, the briefing table in the center of the room, and the transporter being built into the set.
Malcolm McDowellMalcolm McDowell once said he'd like to appear on [DS9], but only if his nephew (Alexander SiddigAlexander Siddig) would direct the episode. Unfortunately, this never panned out, mostly due to scheduling conflicts.
Mark Allen ShepherdMark Allen Shepherd, in addition to his regular role as Morn, appeared as a Bajoran officer (whom Quark asks to sit in Morn's usual place at the bar) in the episode {Who Mourns for Morn?}.
In a scene where Bashir and O'Brien come out of the holo-suite and talk to Quark dressed as WWII RAF pilots, most of O'Brien's jargon comes from a Monty Python sketch, RAF Banter.