.\" $OpenBSD: sd.4,v 1.18 2011/06/05 18:42:05 matthew Exp $ .\" $NetBSD: sd.4,v 1.3 1996/10/20 23:15:23 explorer Exp $ .\" .\" Copyright (c) 1996 .\" Julian Elischer . All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd $Mdocdate: June 5 2011 $ .Dt SD 4 .Os .Sh NAME .Nm sd .Nd SCSI disk driver .Sh SYNOPSIS .Cd "sd* at scsibus?" .Cd "#sd0 at scsibus0 target 3 lun 0" Pq fixed-configuration example .Sh DESCRIPTION The .Nm driver provides support for a .Tn SCSI disk. It allows the disk to be divided up into a set of pseudo devices called .Em partitions . In general the interfaces are similar to those described by .Xr wd 4 . .Pp .Tn SCSI devices have a fairly high level interface to the system and talk to it via a .Tn SCSI host adapter (e.g., .Xr ahc 4 ) . A .Tn SCSI adapter must also be separately configured into the system before a .Tn SCSI disk can be configured. .Pp When the .Tn SCSI adapter is probed during boot, the .Tn SCSI bus is scanned for devices. Any devices found which answer as .Sq Em Direct type devices will be attached to the .Nm driver. .\"In .\".Fx .\"releases prior to 2.1, the first found was attached as .\".Li sd0 , .\"the second .\".Li sd1 , .\"and so on. .\"Beginning in 2.1 it became possible to lock down the assignment of .\"devices on the .\".Tn SCSI .\"bus to particular units of the .\".Nm .\"device; refer to .\".Xr scsi 4 .\"for details on kernel configuration. .Sh PARTITIONING .\"The .\".Nm .\"driver allows the disk to have two levels of partitioning. .\"One layer, called the .\".Dq slice layer , .\"is used to separate the .\".Fx .\"areas of the disk from areas used by other operating systems. .\"The second layer is the native .\".Bx 4.4 .\"partitioning scheme, .\".Xr disklabel 5 , .\"which is used to subdivide the .\".Fx .\"slices into areas for individual filesystems and swap spaces. .\"For more information, see .\".Xr fdisk 8 .\"and .\".Xr disklabel 8 , .\"respectively.) On many systems .Xr disklabel 8 is used to partition the drive into filesystems. On some systems the .Ox portion of the disk resides within a native partition, and another program is used to create the .Ox portion. .Pp For example, the i386 port uses .Xr fdisk 8 to partition the disk into a BIOS level partition. This allows sharing the disk with other operating systems. .\"If an uninitialized disk is opened, the slice table will be .\"initialized with a fictitious .\".Fx .\"slice spanning the entire disk. Similarly, if an uninitialized .\"(or .\".No non- Ns Fx ) .\"slice is opened, its disklabel will be initialized with parameters returned .\"by the drive and a single .\".Sq Li c .\"partition encompassing the entire slice. .Sh IOCTLS The following .Xr ioctl 2 calls apply to .Tn SCSI disks as well as to other disks. They are defined in the header file .Aq Pa sys/disklabel.h . .Bl -tag -width DIOCSDINFO .\".It Dv DIOCSBAD .\"Usually used to set up a bad-block mapping system on the disk. .\".Tn SCSI .\"drive incorporate their own bad-block mapping so this command is not .\"implemented. .It Dv DIOCGDINFO Read, from the kernel, the in-core copy of the disklabel for the drive. This may be a fictitious disklabel if the drive has never been initialized, in which case it will contain information read from the .Tn SCSI inquiry commands. .It Dv DIOCSDINFO Give the driver a new disklabel to use. The driver .Em will not write the new disklabel to the disk. .It Dv DIOCWDINFO Give the driver a new disklabel to use. The driver .Em will write the new disklabel to the disk. .It Dv DIOCLOCK Lock the media cartridge into the device, or unlock a cartridge previously locked. Used to prevent user and software eject while the media is in use. .It Dv DIOCEJECT Eject the media cartridge from a removable device. .It Dv DIOCINQ Read the devices product information. .El .Pp In addition, the .Xr scsi 4 general .Fn ioctl commands may be used with the .Nm driver, but only against the .Sq Li c (whole disk) partition. .Sh NOTES If a removable device is attached to the .Nm driver, then the act of changing the media will invalidate the disklabel and information held within the kernel. To avoid corruption, all access to the device will be discarded until there are no more open file descriptors referencing the device. During this period, all new open attempts will be rejected. When no more open file descriptors reference the device, the first next open will load a new set of parameters (including disklabel) for the drive. .Sh FILES .Bl -tag -width /dev/rsdXXXXX -compact .It Pa /dev/sd Ns Ar u Ns Ar p block mode .Tn SCSI disk unit .Ar u , partition .Ar p .It Pa /dev/rsd Ns Ar u Ns Ar p raw mode .Tn SCSI disk unit .Ar u , partition .Ar p .El .Sh DIAGNOSTICS None. .Sh SEE ALSO .Xr intro 4 , .Xr scsi 4 , .Xr wd 4 , .Xr disklabel 5 , .Xr disklabel 8 , .Xr fdisk 8 .Sh HISTORY The .Nm driver was originally written for .Tn Mach 2.5, and was ported to .Fx by Julian Elischer. It was later ported to .Ox .