NAME
wd —
WD100x compatible hard disk
driver
SYNOPSIS
wd* at atabus? drive ? flags 0x0000
wd* at umass?
options WD_SOFTBADSECT
DESCRIPTION
The
wd driver supports hard disks that emulate the Western
Digital WD100x. This includes standard MFM, RLL, ESDI, IDE, EIDE, and SATA
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
occurred. 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.
NOTES
Certain Seagate Barracuda drives sold around 2003 have a known firmware bug
leading to corrupted write transfers for sector counts n*15 + 1, in
combination with certain ATA controllers, most commonly Silicon Image 3xxx.
Affected drives include, but are not limited to:
- Seagate ST3120023AS
-
- Seagate ST380023AS
-
- Seagate ST360015AS
-
If you have one of these drives, it's recommended to replace the drive. There
used to exist a driver workaround greatly reducing performance, but the code
was completely removed in
NetBSD 8.0.
SEE ALSO
ata(4),
intro(4),
pciide(4),
scsi(4),
umass(4),
wdc(4),
atactl(8),
dkctl(8)
BUGS
The optional software bad sector list does not interoperate well with sector
remapping features of modern disks. To let the disk remap a sector internally,
the software bad sector list must be flushed or disabled before.