root@ttyp0[hdc1]# /sbin/hdparm -d1 /dev/hdc

/dev/hdc:
 setting using_dma to 1 (on)
 using_dma    =  1 (on)
root@ttyp0[hdc1]# /sbin/hdparm  /dev/hdc

/dev/hdc:
 multcount    =  0 (off)
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
 geometry     = 36483/255/63, sectors = 586114704, start = 0
root@ttyp0[hdc1]# /sbin/hdparm -I /dev/hdc

/dev/hdc:

ATA device, with non-removable media
Standards:
        Likely used: 1
Configuration:
        Logical         max     current
        cylinders       0       0
        heads           0       0
        sectors/track   0       0
        --
        device size with M = 1024*1024:           0 MBytes
        device size with M = 1000*1000:           0 MBytes
Capabilities:
        IORDY not likely
        Cannot perform double-word IO
        R/W multiple sector transfer: not supported
        DMA: not supported
        PIO: pio0
root@ttyp0[hdc1]# dd if=/dev/hdc bs=512 count=1 | od -t x1
dd: reading `/dev/hdc': 入力/出力エラーです
読み込んだブロック数は 0+0
書き込んだブロック数は 0+0
0 bytes transferred in 1.180163 seconds (0 bytes/sec)
0000000