Hard-disk drive power consumption reduction methods focus mainly on increasing the amount of time the disk is in standby mode (disk spun down) by implementing aggressive data readahead and caching at the operating system and/or application level. However, these methods cannot be applied efficiently to systems with limited memory and high bit-rate requirements such as digital video recorders handling high-definition video. In this paper, we introduce the Audio/Video File System (AVFS), composed of a file system and a disk I/O scheduler. Compared to traditional methods, the proposed scheduler reduces seek overhead by processing real-time requests to video files using batches built dynamically depending on the requests deadlines. Evaluation results show an important reduction in disk utilization rates and a reduction of up to 20 % of the disk power consumption with only 4 MB of data buffer per video stream. Categories and Subject Descriptors D.4.2 [Operating Systems]: Storage management ...