1. A method for using a memory device with a built-in memory array and a connector for a removable memory device, the method comprising: determining whether a removable memory device connected to a first connector of a memory device comprises a memory controller, wherein the memory device comprises a second connector configured to connect to a host device and also comprises a built-in memory array; if it is determined that the removable memory device does not comprise a memory controller, using circuitry in the memory device to control read/write operations to a memory array in the removable memory device; and if it is determined that the removable memory device does comprise a memory controller, using the memory controller to control read/write operations to the memory array in the removable memory device.