WD(4)                     OpenBSD Programmer's Manual                    WD(4)

NAME
     wd - WD100x compatible hard disk driver

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

DESCRIPTION
     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''.

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

OpenBSD 4.7                      May 31, 2007                                1
