Patent ID: 7079352

Claim:
A magnetic disk apparatus comprising: a plurality of disk enclosures; a plurality of first printed-circuit boards which are paired with said respective disk enclosures; and a second printed-circuit board which is detachably connected to said plurality of first printed-circuit boards; wherein each of said plurality of first printed-circuit boards mounts circuits which have a first noise resistance property, and a circuit which holds parameters unique to a corresponding disk enclosure; wherein said second printed-circuit board mounts circuits which have a second noise resistance property which is superior to said first noise resistance property, wherein said circuits on said second printed-circuit board include a switch for selecting either of one of said plurality of first printed-circuit boards simultaneously connected to a processor on said second printed-circuit board and another of said plurality of first printed-circuit boards simultaneously connected to said processor on said second printed-circuit board, wherein said second printed circuit board is detachably connectable to an upper system, and wherein said circuits on each of said plurality of first printed-circuit boards comprise a recording/reproduction control circuit.