Track-Pairing: a Novel Data Layout for VOD Servers with Multi-Zone-Recording Disks

  • Authors:
  • Yitzhak Birk

  • Affiliations:
  • Technion -- Israel Institute of Technology

  • Venue:
  • ICMCS '95 Proceedings of the International Conference on Multimedia Computing and Systems
  • Year:
  • 1995

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Abstract

Multi-zone recording increases disk capacity by approximating fixed linear recording density. With fixed rotation speed, however, transfer rate varies with track location, as does the number of video streams that can be played concurrently. This paper proposes Track-Pairing, a deterministic scheme for static intra-disk data layout. By recording each movie alternately on "outer" tracks and their "inner" counterparts, a disk's throughput becomes independent of the viewers' choices and its guaranteed streaming capacity is maximized. With a 1.8:1 ratio of outermost to innermost track capacities, guaranteed streaming capacity is increased by 40 percent, and is merely 22 percent below the streaming capacity of the outermost track! Temporal overhead is modest, and required buffer sizes are smaller than those with the Logical Tracks scheme, which also maximizes guaranteed throughput. Track-Pairing has been implemented under Microsoft's Windows NT, and can be extended to multiple disk drives.