Miscellany

192# diskinfo -ct /dev/da0s1f
/dev/da0s1f
        512             # sectorsize
        29416466944     # mediasize in bytes (27G)
        57454037        # mediasize in sectors
        3576            # Cylinders according to firmware.
        255             # Heads according to firmware.
        63              # Sectors according to firmware.

I/O command overhead:
        time to read 10MB block      0.162086 sec       =    0.008 msec/sector
        time to read 20480 sectors  10.084262 sec       =    0.492 msec/sector
        calculated command overhead                     =    0.484 msec/sector

Seek times:
        Full stroke:      250 iter in   1.208320 sec =    4.833 msec
        Half stroke:      250 iter in   1.009736 sec =    4.039 msec
        Quarter stroke:   500 iter in   2.830754 sec =    5.662 msec
        Short forward:    400 iter in   1.550920 sec =    3.877 msec
        Short backward:   400 iter in   1.670365 sec =    4.176 msec
        Seq outer:       2048 iter in   0.898683 sec =    0.439 msec
        Seq inner:       2048 iter in   0.899614 sec =    0.439 msec
Transfer rates:
        outside:       102400 kbytes in   1.512974 sec =    67681 kbytes/sec
        middle:        102400 kbytes in   1.747504 sec =    58598 kbytes/sec
        inside:        102400 kbytes in   2.497016 sec =    41009 kbytes/sec















[root@fusty /usr/ports]# diskinfo -ct /dev/ad0s1a
/dev/ad0s1a
        512             # sectorsize
        9467940352      # mediasize in bytes (8.8G)
        18492071        # mediasize in sectors
        19568           # Cylinders according to firmware.
        15              # Heads according to firmware.
        63              # Sectors according to firmware.

I/O command overhead:
        time to read 10MB block      0.473497 sec       =    0.023 msec/sector
        time to read 20480 sectors   3.514661 sec       =    0.172 msec/sector
        calculated command overhead                     =    0.148 msec/sector

Seek times:
        Full stroke:      250 iter in   5.155973 sec =   20.624 msec
        Half stroke:      250 iter in   3.937509 sec =   15.750 msec
        Quarter stroke:   500 iter in   6.290783 sec =   12.582 msec
        Short forward:    400 iter in   3.246969 sec =    8.117 msec
        Short backward:   400 iter in   2.856887 sec =    7.142 msec
        Seq outer:       2048 iter in   0.406181 sec =    0.198 msec
        Seq inner:       2048 iter in   0.409885 sec =    0.200 msec
Transfer rates:
        outside:       102400 kbytes in   4.563343 sec =    22440 kbytes/sec
        middle:        102400 kbytes in   4.477635 sec =    22869 kbytes/sec
        inside:        102400 kbytes in   4.936842 sec =    20742 kbytes/sec