Fairness of proportional work-conserving I/O scheduling

Proposed is a new I/O scheduling for SSD, proportional work-conserving. The proposed scheduling algorithm provides proportional fairness among tasks. To provide proportional fairness, proportional work-conserving differentiates probability to fully utilise the task's quantum, which is controlled by adjusting opportunistic waiting time. Its proportional fairness is formally proveds and its validity through numerical evaluation and experimental results from Linux implementation are presented.