Jethro Tull took the stage 55 years ago this month with a guitarist wearing a floppy, decidedly un-metal white hat. Turns out, that was Tony Iommi.

Black Sabbath called it a career 10 years ago with ’13,’ an album that mixed and matched sounds from every one of their classic eras.

Ozzy Osbourne’s ‘Ordinary Man’ is extremely difficult to listen to – not because of the content, but because it sounds like utter crap.

Revisiting ‘Black Sabbath’ on the album’s 50th anniversary, it strikes me again just what a defining moment this was in rock.

Competing formats and differing licensing agreements have caused songs by the Beatles, Police, Black Sabbath and others to get lost in the shuffle.

A visit to a pub with Black Sabbath’s Tony Iommi led to Ian Gillan joining Black Sabbath for ‘Born Again,’ released on Aug. 7, 1983.

‘Sabotage,’ released in July 1975, finds Black Sabbath still at the height of its powers, but on the brink of slipping into chaos – and that translates into the music.

An enjoyable compilation capturing a specific time, ‘Heavy Metal: Music From the Motion Picture’ arrived just before rock and pop became mechanical.

Carmine Appice attacks from the right, while Vinny sets up on the left for ‘Drum Wars Live!,’ creating a gloriously thunderous racket.

As we all know, the Devil gets the best tunes — and scripts.