.\"	$OpenBSD: bio.4,v 1.13 2005/11/11 09:35:19 jmc Exp $
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.\" Copyright (c) 2002 Niklas Hallqvist
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.Dd June 8, 2002
.Dt BIO 4
.Os
.Sh NAME
.Nm bio
.Nd ioctl tunnel pseudo-device
.Sh SYNOPSIS
.Cd "pseudo-device bio" Op Ar count
.Sh DESCRIPTION
The
.Nm
driver provides userland applications
.Xr ioctl 2
access to devices otherwise not found as
.Pa /dev
nodes.
The
.Pa /dev/bio
device node operates by delegating ioctl
calls to a requested device driver.
Only drivers which have registered with the
.Nm
device can be accessed via this interface.
.Pp
If
.Ar count
is given in the specification, and is greater than 0, a maximum of one
.Nm bio
device is created.
.Pp
The following ioctl calls apply to the
.Nm bio
device:
.Bl -tag -width BIOCCAPABILITIES
.It Dv 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.
.It Dv BIOCALARM
Control the alarm beeper on the device.
.It Dv BIOCBLINK
Blink an LED on one of the drives (to be replaced).
.It Dv BIOCCAPABILITIES
Return information about ioctl commands, RAID levels, and other
features supported.
.It Dv BIOCPING
Check on the device to see if it's alive.
Increments a counter to signify the OK condition.
.It Dv BIOCSCSICMD
Tunnel a SCSI command into one of the buses on the device.
May not be supported if the device doesn't employ SCSI.
.It Dv BIOCSTARTSTOP
Start or Stop one of the component drives.
.It Dv BIOCSTATUS
Retrieve device status including physical drives, logical drives,
and battery module.
.El
.Sh FILES
.Bl -tag -width /dev/bio -compact
.It Pa /dev/bio
ioctl tunnel device
.El
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr ami 4 ,
.Xr ciss 4 ,
.Xr gdt 4 ,
.Xr bioctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 3.2 .