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Alan Alda, David Ogden Stiers, Jamie Farr and William Christopher in a scene from "M*A*S*H," which ended its run on February 28, 1983.
CNN  — 

“M*A*S*H” ran for 11 seasons, even though the Korean War, during which the CBS series was set, lasted three years. When the show finally signed off 40 years ago – with a special 2.5-hour episode titled “Goodbye, Farewell and Amen” – it set a ratings record that will never be equaled, and indeed, has become virtually impossible in the fragmented media market that exists today.

Broadcast during the period when there were still just three major networks (Fox didn’t sign on until 1986) and cable was in its infancy, the “M*A*S*H” finale drew 106 million viewers, still a record for any episodic series.

More staggeringly, the finale was watched in over 60% of US homes, commanding the attention of more than three out of four TV sets in use (that is, its share of audience), meaning that every other programmer might as well have been running a test pattern.

The population has grown substantially over the last four decades, so recent Super Bowls can surpass the overall audience. But no entertainment program has ever rivaled that “M*A*S*H” milestone, and in an age of countless networks and multiple streaming services, it seems safe to say that none ever will.

“M*A*S*H’s” accomplishments hardly begin and end with ratings trivia. With its mix of wartime drama and broad comedy, the show basically created the template for what became known as the “dramedy,” a hybrid of the two genres that grew increasingly popular in the ’80s and has carried through till today.

The series also changed and replaced key cast members through the duration of its run, often coming out stronger with the new additions.

The constants included star Alan Alda, who, as former CBS executive turned academic Jim McKairnes, now a professor of TV history at Middle Tennessee State University, wrote last year in a USA Today piece marking the 50th anniversary of the show’s debut, exercised greater control of the series during the latter half of its run.

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Alan Alda, foreground, with original "M*A*S*H" cast members Loretta Swit, Wayne Rogers and McLean Stevenson.

Doubling as a writer and director (and winning Emmys for both, as well as acting), Alda helped steer “M*A*S*H” as the show – which, like the movie upon which it was based, premiered during the Vietnam War – “drifted into broader social commentary about the human condition (PTSD, sexism, racism) and the general fog of war,” McKairnes said.

The finale itself underscored those qualities, including a devastating subplot involving an imperiled bus that left Alda’s character, Benjamin “Hawkeye” Pierce,” psychologically scarred and in need of counseling from the visiting psychiatrist, a recurring character played by Allan Arbus.

Other programs had splashy farewells in the years after “M*A*S*H” (the title, incidentally, of a spinoff series that followed it), including “Seinfeld” and “Cheers.” “The Fugitive” also set a high bar in 1967, five years before “M*A*S*H” made its debut, attracting 78 million viewers when its protagonist, Dr. Richard Kimble, finally caught up with the one-armed man he had long protested was the real murderer of his wife. “Roots” also transfixed America and emptied restaurants for eight successive nights in 1977.

Those kind of shared viewing experiences, however, became increasingly rare. For over a decade, “M*A*S*H” began with an image of helicopters ferrying wounded to the 4077 Mobile Army Surgical Hospital (hence the acronym), and it closed, appropriately, with a shot of a chopper heading in the opposite direction as the war, along with the show, finally came to an end.

That image remains an appropriate one, marking the end of a chapter in TV history, as the days of three networks amassing huge audiences almost by default was about to begin its own flight into the sunset.