Using an add-on storage device for extending the storage capacity of a storage device

A storage device, comprising:

• a host interface operative to connect with a host device;
• a storage device interface operative to couple with an add-on memory;
• a memory storing an allocation table having entries for an initial address space of the storage device and entries for an extended address space, prior to coupling the storage device to the add-on memory via the storage device interface at least a subset of the entries for the extended address space are for locations in the add-on memory that will extend the capacity of the storage device at a later time after coupling the add-on memory to the storage device and the entries for the extended address space that are for locations in the add-on memory are marked as unavailable, after coupling the add-on memory to the storage device at least a subset of the entries for the extended address space that are for locations in the add-on memory are marked as available;
• a controller configured to, when the host interface is connected to a host device and the add-on memory is coupled to the storage device:
• receive a data transfer command from the host interface, the data transfer command specifying a memory address, and
• if the memory address is beyond the address space of the memory, route the data transfer command to the storage device interface for access to the add-on memory, wherein the address space of the memory and an address space of the add-on memory are addressed as one integral address space transparently to the host device.

A method for configuring a memory in a storage device mountable to a host device, the storage device having a storage device interface for coupling with an add-on memory, the method comprising:

• prior to coupling the storage device to the add-on memory, formatting the memory to contain a file allocation table with entries beyond the storage capacity of the storage device, the file allocation table having entries associated with an initial address space of the memory and entries associated with an extended address space, the entries associated with the extended address space are for locations in the add-on memory that will extend the capacity of the storage device at a later time;
• and
• prior to coupling the storage device to the add-on memory, marking the entries in the file allocation table that are associated with the extended address space as unavailable, such that if an add-on memory is present and coupled to the memory entries associated with the extended address space are made available according to the address space of the add-on memory,
• wherein the extended address space is addressed as one integral address space within the memory transparently to a connectable host device.

A method for operating a storage device mountable to a host device, the storage device having a storage device interface for coupling to an add-on memory, the method comprising:

• prior to coupling the storage device to the add-on memory, storing in the storage device a file allocation table with entries beyond the storage capacity of the storage device, the file allocation table having entries for an initial address space of the storage device and entries for an extended address space, at least a subset of the entries for the extended address space are for locations in the add-on memory that will extend the capacity of the storage device at a later time, prior to coupling the storage device to the add-on memory the entries in the file allocation table that are for the extended address space are marked as unavailable;
• detecting connection of the add-on memory to the storage device;
• in response to detecting connection of the add-on memory to the storage device, configuring the storage device to use the add-on memory including changing the marking to available of the entries for the extended address space for locations in the add-on memory;
• and
• performing data transfer operations between a host connected to the storage device and the add-on memory via the storage device.