Systems and methods for managing storage devices are provided. The functionalities of smart card and micro SD card are integrated into a storage device to expand the effective storage capacity. The system includes a storage device having a storage area, a microcontroller, and a microprocessor. The microcontroller receives an access request, determines whether the access request conforms to a specific protocol or whether the access request is requesting to activate the microprocessor, and transmits the access request to a microprocessor when the access request conforms to the specific protocol or when the access request is requesting to activate the microprocessor. The microprocessor executes a Card Operating System (COS), and manages the storage area by performing the access request based on the COS. Further, the segmentation of expanded storage space and independent management/security mechanism for segmented spaces also make it possible to perform multi-applications for different card organizations/issuers.