Portable electronic apparatus having a function of checking for empty areas in which to write data

A portable electronic apparatus comprising:

• contactor means, couplable to a portable electronic apparatus handling system, for receiving a write instruction including a write function field, a write area number field, a write data string length field, and a write data string field from said portable electronic apparatus handling system;
• storage means which is divided into a plurality of areas, each of the areas having a pointer data field indicating a final location thereof where data is written, for storing in a specific area at least data for recognizing a final address of each of the areas and a data string supplied from said portable electronic apparatus handling system;
• reading means for reading out from said storage means data recognizing the final address of the area designated by a write area number field of the write instruction and pointer data from said storage means in response to a write instruction supplied from said portable electronic apparatus handling system;
• calculating means for calculating a memory capacity from the values of the final address and the pointer data read by said reading means;
• comparing means for comparing the memory capacity calculated by said calculating means with a value of the write data string length field of the write instruction;
• determining means for determining whether a data string which has been requested to be written can be written entirely;
• and
• writing means for writing the data string to said storage means when said determining means determines that the data string can be written.