Hard disk drive with optional cache memory

A method comprising:

• in a processor performing, while the processor is operatively coupled to a cache interface configured to be detachably connectable to a cache memory:
• in response to power up of the processor, sensing a presence or an absence of the cache memory by interrogation of the cache interface;
• subsequent to the interrogation of the cache interface, determining whether the cache memory is connected to the cache interface by inspecting an indication of a presence or an absence of the cache memory, the indication being stored in a register in the processor or in a random access memory that is coupled to the processor such that the inspection avoids repeat interrogation of the cache interface by the processor;
• communicating with the cache memory and the random access memory such that the processor has access to the cache memory when the cache memory is connected to the cache interface;
• and
• communicating with the random access memory when the cache memory is disconnected from the cache interface.

A hard disk drive system comprising:

• a hard disk drive;
• a processor coupled to the hard disk drive;
• and
• a cache interface integral to the hard disk drive and coupled to the processor, wherein the cache interface includes a slot adapted to receive a flash memory card, wherein the processor is adapted to:
• in response to power up of the processor, sense a presence or an absence of the flash memory card memory by interrogation of the cache interface;
• subsequent to the interrogation of the cache interface, determine whether the flash memory card is coupled to the cache interface by inspecting an indication of a presence or an absence of the flash memory card, the indication being stored in a register in the processor or in a memory associated with the processor, wherein the inspection avoids repeat interrogation of the cache interface;
• communicate with the flash memory card and the hard disk drive to access the flash memory card when the flash memory card is connected to the cache interface;
• and
• communicate with the hard disk drive when the flash memory card is disconnected from the cache interface.