A portable electronic apparatus configured to execute a process based on command input from an external apparatus, and storing a plurality of tag-length-value, TLV, data objects, the apparatus characterized by comprising: a storage unit configured to store at least one file having a first storage area and a second storage area wherein: the first storage area is configured to store, for each TLV data object, a data class and a fixed-length address representing the position of data characters of the corresponding TLV data object, the data class and the fixed-length address being stored in association with each other, and the second storage area is configured to store the data characters of the TLV data objects, wherein the fixed-length address is an offset value between the position at which the fixed-length address is written and the position, at which the data characters of Value of the TLV data object are written in the second storage area, or wherein the fixed-length address is an offset value between the head of the at least one file containing a plurality of TLV data objects coupled to one another and the position, at which the data characters of Value of the TLV data object are written in the second storage area; and a transmission/reception unit configured to transmit and receive data to and from the external apparatus; and a control unit configured such that, if a read command for reading a TLV object is received by the transmission/reception unit, the control unit retrieves from the first storage area the data class that is identical to designation data contained in the read command, and reads the data characters stored in the second storage area based on the fixed-length address associated with the retrieved data class. a storage unit configured to store at least one file having a first storage area and a second storage area wherein: the first storage area is configured to store, for each TLV data object, a data class and a fixed-length address representing the position of data characters of the corresponding TLV data object, the data class and the fixed-length address being stored in association with each other, and the second storage area is configured to store the data characters of the TLV data objects, wherein the fixed-length address is an offset value between the position at which the fixed-length address is written and the position, at which the data characters of Value of the TLV data object are written in the second storage area, or wherein the fixed-length address is an offset value between the head of the at least one file containing a plurality of TLV data objects coupled to one another and the position, at which the data characters of Value of the TLV data object are written in the second storage area; and a transmission/reception unit configured to transmit and receive data to and from the external apparatus; and the first storage area is configured to store, for each TLV data object, a data class and a fixed-length address representing the position of data characters of the corresponding TLV data object, the data class and the fixed-length address being stored in association with each other, and the second storage area is configured to store the data characters of the TLV data objects, wherein the fixed-length address is an offset value between the position at which the fixed-length address is written and the position, at which the data characters of Value of the TLV data object are written in the second storage area, or wherein the fixed-length address is an offset value between the head of the at least one file containing a plurality of TLV data objects coupled to one another and the position, at which the data characters of Value of the TLV data object are written in the second storage area; and a transmission/reception unit configured to transmit and receive data to and from the external apparatus; and a control unit configured such that, if a read command for reading a TLV object is received by the transmission/reception unit, the control unit retrieves from the first storage area the data class that is identical to designation data contained in the read command, and reads the data characters stored in the second storage area based on the fixed-length address associated with the retrieved data class.