BIO(4)

NAME
bio - block I/O ioctl tunnel pseudo-device

SYNOPSIS
pseudo-device bio [count]

DESCRIPTION
The bio driver provides userland applications ioctl(2) access to devices otherwise not found as /dev nodes. The /dev/bio device node operates by delegating ioctl calls to a requested device driver. Only drivers which have registered with the bio device can be accessed via this interface.

If count is given in the specification, and is greater than 0, a maximum of one bio device is created.

The following device drivers register with bio for volume management:

ami(4)
    American Megatrends Inc. MegaRAID PATA/SATA/SCSI RAID controller
arc(4)
    Areca Technology Corporation SAS/SATA RAID controller
cac(4)
    Compaq Smart ARRAY 2/3/4 SCSI RAID controller
ciss(4)
    Compaq Smart ARRAY 5/6 SAS/SATA/SCSI RAID controller
ips(4)
    IBM SATA/SCSI ServeRAID controller
mfi(4)
    LSI Logic & Dell MegaRAID SAS RAID controller
mpi(4)
    LSI Logic Fusion-MPT Message Passing Interface
mpii(4)
    LSI Logic Fusion-MPT Message Passing Interface II
softraid(4)
    Software RAID

The following device drivers register with bio to provide enclosure management:

safte(4)
    SCSI Accessed Fault-Tolerant Enclosure
ses(4)
    SCSI Enclosure Services

The following ioctl calls apply to the bio device:

BIOCLOCATE
    Locate a named device and give back a cookie to the application for subsequent ioctl calls. The cookie is used to tunnel further ioctls to the right device.

BIOCINQ
    Retrieve number of volumes and physical disks for a specific device.

BIOCDISK
    Retrieve detailed information for the specified physical disk. Information returned can include status, size, channel, target, lun, vendor name, serial number and processor device (ses or safte).

BIOCVOL
    Retrieve detailed information for the specified volume. Information returned can include status, size, RAID level, number of disks, device name association (sd?) and vendor name.

BIOCALARM
    Control the alarm beeper on the device. Supported states are: disable alarm, enable alarm, silence alarm, status and test alarm.

    Note: These options might not be supported on all hardware.

BIOCBLINK
    Blink an LED of the specified physical disk. Supported blink states are: blink LED, unblink LED and blink alarm LED.

    Note: This option is only supported if the disk is governed by ses(4) or safte(4) and the hardware supports hardware blinking.

BIOCSETSTATE
    Alter the state of specified physical disk. Supported states are: create hot-spare, online disk and offline disk.

The following ioctl calls apply to the bio device only when talking to a softraid(4) device:

BIOCCREATERAID
    Create a new volume or assemble an existing volume. The volume will be attached as a system disk, if this capability is supported by the volume discipline.

BIOCDELETERAID
    Remove system disk (if present) and disassemble the softraid(4) volume.

BIOCDISCIPLINE
    Dispatch a discipline specific ioctl.

FILES
/dev/bio
    ioctl tunnel device

SEE ALSO
ioctl(2), softraid(4), bioctl(8)

HISTORY
The bio driver first appeared in OpenBSD 3.2.

AUTHORS
-nosplit The bio driver was written by Niklas Hallqvist <niklas@openbsd.org>. The API was written by Marco Peereboom <marco@openbsd.org>.