WD(4) | Device Drivers 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)

May 31, 2007 | Debian