NAME    [Toc]    [Back]

     sd - SCSI disk driver

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     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 configured.


     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    [Toc]    [Back]

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


     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    [Toc]    [Back]

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

     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 SCSI inquiry commands.

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

     DIOCWLABEL   Enable  or  disable the driver's software write
protect of the
                 disklabel on the disk.

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

     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.

     DIOCEJECT    Eject  the media cartridge from a removable device.

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

NOTES    [Toc]    [Back]

     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    [Toc]    [Back]

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

DIAGNOSTICS    [Toc]    [Back]

     None.

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

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

OpenBSD      3.6                         January     18,     1996