"Rag Mop" was a popular American song of the late 1940s-early 1950s. Considered a novelty song, the lyrics consisted mostly of spelling out the title of the song; because of the spelling used in the song, it is sometimes referred to as "Ragg Mopp."
This song was played on M*A*S*H in Season 9, Episode 6, after Hawkeye and BJ ordered a radio from the Sears Catalog. The song drives Major Winchester nuts as he is a strict classical music lover ("Those people can neither sing nor spell!")
Many bands and performers recorded this song, but only the Ames Bros. had a bigger hit with it than did Flanagan & Orchestra.
Info on Ralph Flanagan (now deceased) is scarce; his Wiki page is a scant 6 paragraphs:
'Ralph Flanagan (born Ralph Elias Flenniken; 1914 - 1995) was a famed big band leader, conductor, pianist, composer, and arranger for the orchestras of Hal McIntyre, Sammy Kaye, Blue Barron, Charlie Barnet, and Alvino Rey.
During World War II he served in the Merchant Marine from October 1942 to 1946. Somewhere along the way, he married Hannah Wingert.
By 1949 he formed a very successful orchestra which is credited with re-popularizing the Glenn Miller "sound," and which made many records, among them "Singing Winds","Rag Mop" and "Hot Toddy."
The Flanagan orchestra's theme songs were "Giannina Mia" and "Singing Winds", the latter title also applying to the orchestra's singing group.'From Big Band Librbary:
'He was voted the "favorite band" in a number of early 1950s polls, played for over two million people in a year's time, and racked up big grosses, including some $600,000 in 1951 alone.*For this, and more original hits from the 40's, 50's, 60's, and beyond, tune into John Christopher's streaming 24/7 musical extravaganza "The Neon Beat" by clicking here, or click the icon on the side of this page.
...(paradoxically) He was really not a guy that enjoyed the spotlight at all. He had been mainly a 'background' man.'
(disclaimer: the views expressed here are my own and not affiliated with John Christopher or The Neon Beat. I'm simply a fan of the show.)