| BIO(4) | Kernel Interfaces Manual | BIO(4) | 
NAME
 bio — Block IO ioctl tunnel pseudo-device
SYNOPSIS
 pseudo-device bio
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.
The following device drivers register with bio for volume management:
- 
arcmsr(4)
- 
Areca Technology Corporation SATA RAID controller
- 
cac(4)
- 
Compaq RAID array controller
- 
ciss(4)
- 
Compaq Smart ARRAY 5/6 SAS/SATA/SCSI RAID controller
- 
mfi(4)
- 
LSI Logic & Dell MegaRAID SAS RAID controller
- 
mpt(4)
- 
LSI Fusion-MPT RAID controller
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).
- 
BIOCDISK_NOVOL
- 
Is just the same as BIOCDISK but doesn't require the disks to be in volume sets, so this applies to any physical disk connected to the controller.
Note: this ioctl might not be supported on all hardware. 
- 
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) and the hardware supports hardware blinking. 
- 
BIOCSETSTATE
- 
Alter the state of specified physical disk. Supported states are: create/remove hot-spare, create/remove pass through disk, start/stop consistency check in a volume, online disk and offline disk.
Note: These options might not be supported on all hardware. 
- 
BIOCVOLOPS
- 
For operations in volume sets. It's able to create and remove a volume set in a supported RAID controller.
Note: this ioctl might not be supported on all hardware. 
 
FILES
- 
/dev/bio
- 
ioctl tunnel device
 
HISTORY
 The bio driver first appeared in OpenBSD 3.2 and NetBSD 4.0.