It is known that amorphous continuous media such as TbFeCo have extremely low noise characteristics because of the structure of the continuous grainless medium. There is great interest in the use of amorphous media in magnetic recording. This study investigated the recording characteristics of the amorphous continuous medium by computer simulation using the Landau-Lifshitz-Gilbert equation. It was shown that the transition of the continuous medium is very sharp and the noise level very low. It was also shown that the recorded magnetization patterns of the continuous medium are distinct at the high recording density of 380 Gbit/inch2. We concluded that the continuous medium has great potential for use in ultra-high density recording.

To understand the characteristics of a multimedia service, such as the large volume of data transfer and real-time constraints, it is necessary to have a performance evaluation tool for an HDD. Our HDD simulator is running on a PC operated on FreeBSD UNIX OS. We first investigate the seek time and the sustained rate of HDDs and then evaluate the performance of an HDD for an experimental VOD system. Applying the experimental results, we find the bottleneck of an HDD, and then suggest what HDDs are to be selected for a VOD system.