MirBSD manpage: wd(4)
WD(4) BSD Programmer's Manual WD(4)
wd - WD100x compatible hard disk driver
wd* at wdc? channel ? drive ? flags 0x0000
wd* at pciide? channel ? drive ? 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.
The flags are used only with controllers that support DMA operations and
mode settings (like some pciide(4) controllers). The lowest order (right-
most) 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)
MirBSD #10-current October 15, 1998 1