Minimizing Service Time for a Fixed Number of Active Tips

In reality, design of a probe-based storage device is likely to be constrained by cost. We approximate this by fixing the number of active tips at 320 (assuming that the number of tips is proportional to the cost of the device) and determining a configuration that minimizes service time.

Figure 8b shows the configurations that minimize the service time for each workload. Figure 8a shows the service time when the movement range in $Y$ is varied. Our model again does an accurate prediction of where the minimum service time occurs for all four workloads. In the case of snake, cello99 and cello92 this is just around 30$\mu$m, while in the case of tpcd this happens at the upper bound for the movement range in $Y$, 80$\mu$m. This makes sense because the tpcd workload has larger request sizes and runlengths, and therefore can benefit from the fewer turnarounds offered by long movements in $Y$.