CPC Subgroup
G11B 5/004 Recording on, or reproducing or erasing from, magnetic drums (G11B19/00 takes precedence)
Full Title
Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor (G11B11/00 take precedence) > Recording on, or reproducing or erasing from, magnetic drums (G11B19/00 takes precedence)