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WD(4) Device Drivers Manual WD(4)

wdWD100x compatible hard disk driver

wd* at wdc? flags 0x0000
wd* at pciide? flags 0x0000

The wd driver supports hard disks which emulate the Western Digital WD100x. This includes standard MFM, RLL, ESDI, IDE, and EIDE drives, as well as Serial ATA drives, and PCMCIA/CF storage media.

The flags are used only with controllers that support DMA operations and mode settings (like some pciide(4) controllers). The lowest order (rightmost) nibble of the flags define the PIO mode to use. The next four bits indicate the DMA mode and the third nibble the UltraDMA mode.

For each set of four bits, the 3 lower bits define the mode to use and the last bit must be set to 1 for this setting to be used. For DMA and UltraDMA, 0xf (1111) means “disable”. For example, a flags value of 0x0fac (1111 1010 1100) means “use PIO mode 4, DMA mode 2, disable UltraDMA”. The special setting 0x0000 means “use whatever the drive claims to support”.

intro(4), pciide(4), scsi(4), wdc(4), disklabel(5), atactl(8), disklabel(8), fdisk(8)

May 31, 2007 OpenBSD-5.3