Black Sabbath's 1970s Albums to Be Sold on iTunes The very short list of high-profile artists whose music is not on digital services just got a little shorter with the arrival of Black Sabbath's classic 1970s albums on iTunes. The band's early records, like "Paranoid" in 1970 and "Master of Reality" in 1971, all but defined the sludgy metal of the era, and taught generations of 14-year-olds to nod their heads while plucking out "Iron Man" on the guitar. But these albums have been missing from the vast digital music marketplace, even as Black Sabbath's later material went up on iTunes and Spotify like everything else. On Tuesday the band and its label, Warner Brothers, announced that iTunes had started selling its first eight studio albums, along with three compilations. But iTunes" window of exclusivity is expected to be short. According to people briefed on the deal who were not authorized to speak about it, Black Sabbath's music should come to streaming services in about a week. With the kind of candor that makes you believe no one ghost-writes his quotes, Ozzy Osbourne said that it was "about time" - with another word added in there - that the albums came out digitally. Tony Iommi, the guitarist, said that it had "been a long time trying to explain to fans why the music wasn't available." Although Mr. Iommi didn't elaborate, it has been well known in the music business that the delay was the result of longstanding squabbling between Warner and the band. Representatives of Black Sabbath and the label did not respond to requests for further comment. The classic lineup of Black Sabbath - Mr. Osbourne, Mr. Iommi, the bassist Geezer Butler and the drummer Bill Ward - have reunited various times since the late 1990s. Most recently, three-fourths of the group got together for a new album, "13," released last year. Mr. Ward refused to participate, saying that he had not been given a fair contract. For years many top-selling older artists resisted selling their music digitally because they disliked splitting up their work into a la carte songs, or thought it would cut into more profitable CD sales. But with iTunes more than a decade old now, and CD sales just a fraction of what they were at their peak, most holdouts have decided to play ball. Even Frank Zappa's long-absent catalog is available, for example, although Garth Brooks, Tool and most of Bob Seger's albums are absent. The new frontier has moved to streaming services like Spotify, Rhapsody and the new Beats Music, but there too the list of holdouts is short. Last month, for example, Led Zeppelin announced an exclusive deal with Spotify.