Multimedia file systems survey: approaches for continuous media disk scheduling

• Authors: Ralf Steinmetz
• Venue: Computer Communications
• Year: 1995

We understand multimedia data processing as the handling of audio and video data together with traditional data like text and images. This multimedia data is to be stored with and by a multimedia file system which comprises one or more of the following three issues: (1) The file system can rely on various types of different physical storage devices; however, we usually encounter the same devices as in any other high performance computers; (2) the organization of files in a contiguous order and the data structuring with ropes and strands improves the throughput at the expense of additional management effort; (3) the main goal of traditional disk scheduling is to reduce the cost of seek operations, to achieve a high throughput, and to provide a fair disk access. In multimedia disk scheduling the main goal is to meet all deadlines of the time critical tasks. The buffer requirement should be kept low, and aperiodic requests should not starve, i.e. a balance between the time constraints and efficiency must be found. This paper presents a survey of these three issues, with the focus on disk scheduling. It shows how the traditional disk scheduling techniques 'first come first serve', 'shortest seek time first', SCAN and C-SCAN are enhanced or substituted by EDF, SCAN-EDF, 'group sweeping scheduling', a 'mixed strategy' and a 'continuous media file system' approach.