Shared disk configuration in a multiple actuator hard disk drive

A hard disk drive (HDD) head-stack assembly (HSA) comprising:

• a plurality of actuator arms each coupled with at least one head slider comprising a read-write transducer, and wherein each of an outer actuator arm and at least one inner actuator arm is coupled with two head sliders;
• a flexible printed circuit (FPC) coupled with an actuator carriage;
• and
• a suspension coupling each actuator arm with a corresponding head slider, each suspension comprising a suspension tail comprising electrical traces between each head slider and a respective portion of the FPC;
• wherein:
• a first distance between the two head sliders of the outer actuator arm is greater than a second distance between the two head sliders of the at least one inner actuator arm;
• the suspension tail of the outer actuator arm is configured such that an FPC end of the suspension tail is farther in a z-height direction from an outer-most head slider corresponding to the outer actuator arm than a slider end of the suspension tail.

A hard disk drive multi-actuator system, the system comprising:

• a first actuator assembly comprising a first head-stack assembly (HSA) comprising a plurality of first arms each coupled with a first head slider comprising a read-write transducer configured to write to and to read from disk media;
• a second actuator assembly comprising a second head-stack assembly (HSA) comprising a plurality of second arms each coupled with a second head slider comprising a read-write transducer configured to write to and to read from disk media;
• a plurality of disk media rotatably mounted on a spindle, including:
• a shared disk medium including a top surface positioned for operation with a first head slider of a first arm of the first HSA, the first arm positioned above the shared disk medium, and a bottom surface positioned for operation with a second head slider of a second arm of the second HSA, the second arm positioned below the shared disk medium,
• an upper adjacent disk medium positioned adjacently above the shared disk medium,
• one or more upper disk media above the upper adjacent disk medium,
• a lower adjacent disk medium positioned adjacently below the shared disk medium, and
• one or more lower disk media below the lower adjacent disk medium;
• wherein:
• the first arm positioned above the shared disk medium includes an arm tip having a first thickness;
• at least one other first arm of the first HSA includes an arm tip having a second thickness;
• the second arm positioned below the shared disk medium includes an arm tip having the first thickness;
• at least one other second arm of the second HSA includes an arm tip having the second thickness;
• and
• the first thickness is greater than the second thickness.