.\"	$NetBSD: dk.4,v 1.13 2021/01/06 18:05:58 wiz Exp $
.\"
.\" Copyright (c) 2006 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Jason R. Thorpe.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\"    notice, this list of conditions and the following disclaimer.
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.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" Jonathan A. Kollasch used vnd(4) as the template for this man page.
.\"
.Dd January 6, 2021
.Dt DK 4
.Os
.Sh NAME
.Nm dk
.Nd disk partition
.Pq wedge
driver
.Sh SYNOPSIS
.Cd "options DKWEDGE_AUTODISCOVER"
.Cd "options DKWEDGE_METHOD_BSDLABEL"
.Cd "options DKWEDGE_METHOD_GPT"
.Cd "options DKWEDGE_METHOD_MBR"
.Cd "options DKWEDGE_METHOD_RDB"
.Cd "options DKWEDGE_METHOD_APPLE"
.Sh DESCRIPTION
The
.Nm
driver provides a disk-like interface, or
.Em wedge ,
to an area of a physical disk.
Wedges may be configured manually with
.Xr dkctl 8
or automatically by the kernel upon the attachment of the physical disk.
.Pp
Wedges need to have unique names.
If a duplicate name is detected during
auto-discovery, that partition is ignored.
.Sh KERNEL OPTIONS
.Bl -tag -width DKWEDGE_METHOD_BSDLABEL
.It Dv DKWEDGE_AUTODISCOVER
Automatically detect and configure wedges using any available methods.
.Pp
Currently only
.Dv DKWEDGE_METHOD_GPT
and
.Dv DKWEDGE_METHOD_APPLE
are enabled by default.
.Pp
For each partition found, a wedge with a corresponding name is created.
.It Dv DKWEDGE_METHOD_BSDLABEL
BSD disklabel detection method.
For each configured partition in the
.Xr disklabel 5
that is not of type
.Dv FS_UNUSED ,
a wedge is created and named after the
.Va d_packname
field followed by
.Sq \&/
and the partition letter
.So a Sc Ns \&.. Ns So p Sc .
.Pp
When the
.Va d_packname
is empty or has the value
.Dq fictitious ,
the regular partition names
are used as wedge names, i.e. the device name, unit number and
partition letter, for example
.Dq wd0a .
.It Dv DKWEDGE_METHOD_GPT
Extensible Firmware Interface Globally Unique Identifier Partition Table
(GPT) detection method.
.Pp
For every GPT partition a wedge is created and named after the
partition label.
GPT partitions are UTF-16-encoded, this is converted into UTF-8.
If a partition has no label, its UUID is used instead.
.It Dv DKWEDGE_METHOD_MBR
IBM PC-compatible Master Boot Record (MBR) partitioning detection method,
with support for Extended MBRs.
.Pp
For every partition in the MBR a wedge is created and named like a
regular partition name, i.e. the device name, unit number and a
partition letter, for example
.Dq wd0e .
Primary partitions start with
.Sq e ,
extended partitions start with
.Sq i .
.It Dv DKWEDGE_METHOD_RDB
Amiga Rigid Disk Block (RDB) partitioning detection method.
.It Dv DKWEDGE_METHOD_APPLE
Apple partition map detection method.
.El
.Sh FILES
.Bl -tag -width /dev/XXrXdkX -compact
.It Pa /dev/{,r}dk*
.Nm
device special files.
.El
.Sh SEE ALSO
.Xr config 1 ,
.Xr disklabel 8 ,
.Xr dkctl 8 ,
.Xr fdisk 8 ,
.Xr gpt 8 ,
.Xr MAKEDEV 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Nx 3.0 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Jason R. Thorpe .