一、引言在六十年代前半期,就开始进行光学存储器的研究,并对各种方法、方案进行了尝试,然而至今尚未达到实用水平。最近,对于逐点记录式的补写型光盘装置,半导体激光器、光盘介质等基本技术业已齐备,大容量外存装置已开始商品化。目前,虽然磁记录装置在外存装置范围内占有绝对的地位。 I. INTRODUCTION In the first half of the sixties, optical memory research was started, and various methods and schemes were tried. However, no practical level has been reached so far. Recently, basic technologies such as semiconductor lasers and optical disk media have become available for point-by-point optical write-once optical disk drives, and large-capacity external storage devices have begun to be commercialized. At present, although the magnetic recording device occupies an absolute position within the scope of the external memory device.