A.讀寫(xiě)數(shù)據(jù)時(shí)與具體的機(jī)器無(wú)關(guān)
B.讀寫(xiě)數(shù)據(jù)時(shí)與具體的機(jī)器有關(guān)
C.讀數(shù)據(jù)時(shí)與機(jī)器有關(guān),而寫(xiě)數(shù)據(jù)時(shí)與機(jī)器無(wú)關(guān)
D.讀數(shù)據(jù)時(shí)與機(jī)器無(wú)關(guān),而寫(xiě)數(shù)據(jù)時(shí)與機(jī)器有關(guān)