There was a time when "dd" was the only game in town for deep copies on Unix systems. E.g. HPUX in the 1980s. It always had issues of course: e.g. if the sour

There was a time when "dd" was the only game in town for deep copies on Unix systems. E.g. HPUX in the 1980s. It always had issues of course: e.g. if the source was a 100MB drive and you dd'ed to a blank 200MB, you'd get a new 100MB drive and all the rest was lost because it was a low level copy. Similarly any bad sectors on the old drive became bad sectors on the new and any bad sectors on the new were simply used as if they were OK.