Multiple Partitions

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With hard drives of 40 GB and more becoming the norm, multiple partitions have become a necessity. For better ease of management, each partition can be used for a different function. For the sake of simplicity, suppose that we have three equally sized logical volumes: C: hosts the operating system, D: is reserved for applications, and E: holds data files. Unfortunately, such an arrangement wreaks havoc with optimization. Instead of an exact physical beginning, middle, and end, one ends up with three logical beginning, middle, and end locations dispersed throughout one physical disk. Due to such an arrangement, all of these partitions can be accessed at more or less the same time. The NSTL white paper covers this topic in detail, but, to summarize, the user issues a command to the application (partition D: is accessed), the application makes calls to an operating system function (partition C: is accessed), and then the data is searched for and located (partition E: is accessed). The read/write heads are moving back and forth across the disk in a random pattern; thus, it becomes virtually impossible to place frequently accessed files on the "edge" of a multiple-partition disk.

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