External storage apparatus, control apparatus therefore, and data transmission/reception apparatus

摘要

A memory card (2) is designed to prevent erroneous erasure of stored data or writing other data on the data as well as to enable easy switching of an erroneous erasure prevention switch (23). A command generator (35), upon reception of a register instruction for checking a state of the memory card (2) received via an S/P & P/S sequencer (31), sets a state of the erroneous erase prevention switch (23) in a register and transmits this register content via the S/P & P/S sequencer (31) to a host computer (1). According to the register content from the memory card (2), the host computer (1) decides whether a write protect is ON and executes write inhibit processing when the write protect is ON. <IMAGE>