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SD(4)		       FreeBSD Kernel Interfaces Manual			 SD(4)

NAME
     sd	-- SCSI	disk driver

SYNOPSIS
     sd* at scsibus?
     #sd0 at scsibus0 target 3 lun 0 (fixed-configuration example)

DESCRIPTION
     The sd driver provides support for	a SCSI disk.  It allows	the disk to be
     divided up	into a set of pseudo devices called partitions.	 In general
     the interfaces are	similar	to those described by wd(4).

     SCSI devices have a fairly	high level interface to	the system and talk to
     it	via a SCSI host	adapter	(e.g., ahc(4)).	 A SCSI	adapter	must also be
     separately	configured into	the system before a SCSI disk can be config-
     ured.

     When the SCSI adapter is probed during boot, the SCSI bus is scanned for
     devices.  Any devices found which answer as `Direct' type devices will be
     attached to the sd	driver.

PARTITIONING
     On	many systems disklabel(8) is used to partition the drive into filesys-
     tems.  On some systems the	OpenBSD	portion	of the disk resides within a
     native partition, and another program is used to create the OpenBSD por-
     tion.

     For example, the i386 port	uses fdisk(8) to partition the disk into a
     BIOS level	partition.  This allows	sharing	the disk with other operating
     systems.

IOCTLS
     The following ioctl(2) calls apply	to SCSI	disks as well as to other
     disks.  They are defined in the header file <sys/dkio.h>.

     DIOCGDINFO	struct disklabel *
	     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 SCSI inquiry commands.

     DIOCSDINFO	struct disklabel *
	     Give the driver a new disklabel to	use.  The driver will not
	     write the new disklabel to	the disk.

     DIOCWDINFO	struct disklabel *
	     Give the driver a new disklabel to	use.  The driver will write
	     the new disklabel to the disk.

     DIOCLOCK int *
	     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.

     DIOCEJECT
	     Eject the media cartridge from a removable	device.

     DIOCINQ struct dk_inquiry *
	     Read the devices product information.

     In	addition, the scsi(4) general ioctl() commands may be used with	the sd
     driver, but only against the `c' (whole disk) partition.

NOTES
     If	a removable device is attached to the sd 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.

FILES
     /dev/sdup	    block mode SCSI disk unit u, partition p
     /dev/rsdup	    raw	mode SCSI disk unit u, partition p

DIAGNOSTICS
     None.

SEE ALSO
     intro(4), scsi(4),	wd(4), disklabel(5), disklabel(8), fdisk(8)

HISTORY
     The sd driver was originally written for Mach 2.5,	and was	ported to
     FreeBSD by	Julian Elischer.  It was later ported to OpenBSD.

FreeBSD	13.0			 July 2, 2014			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | PARTITIONING | IOCTLS | NOTES | FILES | DIAGNOSTICS | SEE ALSO | HISTORY

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