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WD(4) NetBSD Kernel Interfaces Manual WD(4)
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wd -- WD100x compatible hard disk driver
wd* at atabus? drive ? flags 0x0000
wd* at umass?
The wd driver supports hard disks that emulate the Western Digital
WD100x. This includes standard MFM, RLL, ESDI, IDE, and EIDE drives.
The flags are used only with controllers that support DMA operations and
mode settings (like some pciide controllers). The lowest order nibble
(rightmost digit) of the flags defines the PIO mode, the next four bits
define the DMA mode and the third nibble defines 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 UDMA,
0xf (1111) means 'disable'. For example, a flags value of 0x0fac (1111
1010 1100) means 'use PIO mode 4, DMA mode 2, disable UltraDMA'. 0x0000
means "use whatever the drive claims to support."
The kernel configuration option ``options WD_SOFTBADSECT'' enables a
software managed bad-sector list which will prevent further accesses to
sectors where an unrecoverable read error occured. A user interface is
provided by dkctl(8). Unlike the (historical) mechanisms provided by
bad144(8) and badsect(8) the software list does neither support sector
replacement nor is it saved across reboots.
ata(4), intro(4), pciide(4), scsi(4), umass(4), wdc(4), atactl(8),
The optional software bad sector list does not interoperate well with
sector remapping features of modern disks. To let the disk remap a sec-
tor internally, the software bad sector list must be flushed or disabled
NetBSD 4.0 August 30, 2004 NetBSD 4.0