Disk drive employing a preamp comprising read/write pass throughs for cascading integrated circuits

A preamp for use in a disk drive, the disk drive comprising a plurality of disk surfaces and a plurality of corresponding heads, the preamp comprising:

• a first integrated circuit coupled to a first plurality of the heads, wherein the first integrated circuit comprising:
• a first read-output for outputting a preamplified read signal;
• a first write-input for receiving a first write signal;
• a write-output-passthrough for outputting a passthrough write signal in response to the first write signal;
• a read-input-passthrough for receiving a passthrough read signal;
• and
• a second integrated circuit coupled to a second plurality of the heads,
• wherein the second integrated circuit comprising:
• a second read-output for outputting the passthrough read signal;
• a second write-input for receiving the passthrough write signal,
• wherein the preamp is configurable to select one of the heads during a read operation, and the preamp is configurable to select one of the heads during a write operation.

A method of operating disk drive, the disk drive comprising a plurality of disk surfaces and a plurality of corresponding heads, and a preamp comprising:

• a first integrated circuit coupled to a first plurality of the heads, wherein the first integrated circuit comprising:
• a first read-output for outputting a preamplified read signal;
• a first write-input for receiving a first write signal;
• a write-output-passthrough for outputting a passthrough write signal in response to the first write signal;
• a read-input-passthrough for receiving a passthrough read signal;
• and
• a second integrated circuit coupled to a second plurality of the heads, wherein the second integrated circuit comprising:
• a second read-output for outputting the passthrough read signal;
• a second write-input for receiving the passthrough write signal;
• and
• the method comprising:
• configuring the preamp to select one of the heads during a read operation, and configure the preamp to select one of the heads during a write operation;
• processing the preamplified read signal at the read-output of the first integrated circuit during the read operation;
• and
• applying the first write signal to the write-input of the first integrated circuit during a write operation.