WD(4) BSD Programmer's Manual WD(4)NAMEwd - ST-506 (MFM/RLL) and IDE hard disk driver
SYNOPSIS
wd* at wdc? drive ?
DESCRIPTION
This is a driver for disks on ST-506 (MFM and RLL) or IDE controllers. It
must be a child of the wdc controller driver. Only drive 0 (master) and
drive 1 (slave) are supported on each controller due to the nature of the
hardware. A slave without a master is not supported when using ATA
(IDE). If an IDE drive supports DMA and is configured via a PCI adapter
that supports DMA (see pciwdc(4)), data transfers use DMA by default.
Drives that support Logical-Block Addressing (LBA) mode use that mode by
default.
Several aspects of the driver operation can be controlled by flags, which
can be set numerically in the kernel configuration file or with the -dev
command from the boot command line or in /etc/boot.default(5).
The first bit (0x1) of the flags argument, when set, causes the driver
always to transfer data at one sector per interrupt (normally a compiled
in default number of sectors per interrupt are used on drives that sup-
port the read multiple and write multiple commands).
If a drive appears not to be ready when the system probes it, the drive
is normally not configured; however, setting the second bit (0x2) of the
flags field will cause a wait of up to 10 seconds for a slave drive to
spin up.
For backward compatibility, the third bit (0x4) of the flags argument,
when set, causes the driver to enable IDE DMA mode on controllers and
drives that support it.
The disk should be labeled with disksetup(8) before use. Bad sectors are
identified and remapped using diskdefect(8).
The disk may optionally contain a DOS fdisk label, and portions of the
disk may be reserved for other operating systems.
BOOT PARAMETERS
The following drive parameters can be configured from boot(8) with the
-parm command. Typically these commands would be added to boot.default(5)
though they can be set at the ``Boot:'' prompt. They can be set for in-
dividual drives by number, or for all drives not explicitly listed when
specified for ``wd*''.
is_mapped forces the drive geometry from the BIOS to be consid-
ered as logical. This is the default with most larger
IDE drives.
use_dma If this parameter is specified as ``no'', DMA is dis-
abled unless flag bit 0x4 is set (see above).
use_lba If this parameter is specified as ``no'', Logical-
Block Addressing is disabled, and Cylinder/Head/Sector
addressing is used instead.
FILES
/dev/wd[0-7][a-h] block files
/dev/rwd[0-7][a-h] raw files
SEE ALSOdiskdefect(8), pciwdc(4), wdc(4), wdpi(4), disksetup(8)HISTORY
The wd driver first appeared in Berkeley Networking-2.
BSDI BSD/OS May 3, 2001 2