*6.24
T_seek = 3 ms T_maxrotate = 60*1000/12000 ms = 5 ms
T_avgrotate = 0.5*T_maxrotate = 2.5 ms
T_transfer = T_maxrotate/500 = 0.01 ms T = T_seek + T_avgrotate + T_transfer = 5.51 ms
第六章课后作业
原文：http://www.cnblogs.com/disturbia/p/4955393.html
