System and method for scheduling of random commands to minimize impact of locational uncertainty
    3.
    发明授权
    System and method for scheduling of random commands to minimize impact of locational uncertainty 失效
    用于调度随机命令的系统和方法,以最小化位置不确定性的影响

    公开(公告)号:US06763404B2

    公开(公告)日:2004-07-13

    申请号:US09916029

    申请日:2001-07-26

    IPC分类号: G06F1200

    CPC分类号: G06F3/0601 G06F2003/0697

    摘要: A system and method are provided for hard disk drive command queue ordering with locational uncertainty of commands. For each command in the hard disk drive command queue, an expected access time is calculated utilizing a probability distribution for a currently executing command and a probability distribution for a candidate command. A command in the hard disk drive command queue having a minimum calculated expected access time is identified. Then the identified command having a minimum calculated expected access time is executed. The probability distribution for a currently executing command represents an ending location distribution for the currently executing command. The probability distribution for a candidate command represents a starting location distribution for the candidate command. For an estimated seek time of less than a time for one full revolution, a probability of a miss multiplied by a time of one extra revolution and multiplied by a candidate arrival probability is calculated and the result is added to an estimated seek time to provide the expected access time. For an estimated seek time of greater than a time for one full revolution, a probability of a make multiplied by a time of one extra revolution and multiplied by a candidate arrival probability is calculated and the result is subtracted from an estimated seek time to provide the expected access time.

    摘要翻译: 提供了一种用于硬盘驱动器命令队列排序的系统和方法,具有命令的位置不确定性。 对于硬盘驱动器命令队列中的每个命令,使用当前执行的命令的概率分布和候选命令的概率分布来计算期望的访问时间。 识别具有最小计算的预期访问时间的硬盘驱动器命令队列中的命令。 然后执行具有最小计算的预期访问时间的所识别的命令。 当前执行的命令的概率分布表示当前执行的命令的结束位置分布。 候选命令的概率分布表示候选命令的起始位置分布。 对于一个完整的旋转小于一个时间的估计的寻道时间,计算一个额外的一次旋转的乘以乘以候选到达概率的概率,并将该结果加到估计的寻道时间,以提供 预期访问时间。 对于大于一个全转的时间的估计搜索时间,计算乘以乘以一个额外的旋转时间并乘以候选到达概率的概率,并且从估计的搜索时间中减去结果以提供 预计访问时间。