Disk-based storage device having read channel memory that is selectively accessible to disk controller

A processing system comprising:

• a processing device;
• and
• a storage device coupled to the processing device and comprising at least one storage disk;
• wherein the storage device further comprises:
• a read/write head configured to read data from and write data to the storage disk;
• and
• control circuitry coupled to the read/write head and configured to process data received from and supplied to the read/write head and to control positioning of the read/write head relative to the storage disk;
• wherein the control circuitry comprises:
• a disk controller;
• and
• read channel circuitry comprising a read channel memory;
• the control circuitry being configured to selectively permit the disk controller to access the read channel memory, wherein the disk controller is permitted to access the read channel memory when the read channel circuitry is not performing a read operation.