抄録
Five year R&D project of optical disk systems finished in March, 2003. The project was funded by Japanese Government and carried out as the project of OITDA by 12 companies and one university. The recording density target of the project was 100Gb/(in)^2. To achieve them, four technologies : ultra high precision pit writing by using electron beam, ultra high precision pit measurement, three dimensional magneto-optical memory, and ultra high density ROM were developed. This paper introduces the outline of the project.