<s>
The	O
bio(4 )	O
pseudo-device	B-Application
driver	O
and	O
the	O
bioctl(8 )	O
utility	O
implement	O
a	O
generic	O
RAID	B-Architecture
volume	O
management	O
interface	B-Application
in	O
OpenBSD	B-Operating_System
and	O
NetBSD	B-Device
.	O
</s>
<s>
The	O
idea	O
behind	O
this	O
software	O
is	O
similar	O
to	O
ifconfig	B-Protocol
,	O
where	O
a	O
single	O
utility	O
from	O
the	O
operating	B-General_Concept
system	I-General_Concept
can	O
be	O
used	O
to	O
control	O
any	O
RAID	B-Device
controller	I-Device
using	O
a	O
generic	O
interface	B-Application
,	O
instead	O
of	O
having	O
to	O
rely	O
on	O
many	O
proprietary	B-Application
and	O
custom	O
RAID	B-Architecture
management	O
utilities	O
specific	O
for	O
each	O
given	O
hardware	O
RAID	B-Architecture
manufacturer	O
.	O
</s>
<s>
Features	O
include	O
monitoring	O
of	O
the	O
health	O
status	O
of	O
the	O
arrays	O
,	O
controlling	O
identification	O
through	O
blinking	O
the	O
LEDs	O
and	O
managing	O
of	O
sound	O
alarms	O
,	O
and	O
specifying	O
hot	B-General_Concept
spare	I-General_Concept
disks	I-General_Concept
.	O
</s>
<s>
Additionally	O
,	O
the	O
softraid	O
configuration	O
in	O
OpenBSD	B-Operating_System
is	O
delegated	O
to	O
bioctl	O
as	O
well	O
;	O
whereas	O
the	O
initial	O
creation	O
of	O
volumes	O
and	O
configuration	O
of	O
hardware	O
RAID	B-Architecture
is	O
left	O
to	O
card	O
BIOS	B-Operating_System
as	O
non-essential	O
after	O
the	O
operating	B-General_Concept
system	I-General_Concept
has	O
already	O
been	O
booted	O
.	O
</s>
<s>
Interfacing	O
between	O
the	O
kernel	O
and	O
userland	O
is	O
performed	O
through	O
the	O
ioctl	B-Operating_System
system	O
call	O
through	O
the	O
/dev/bio	O
pseudo-device	B-Application
.	O
</s>
<s>
The	O
bio/bioctl	O
subsystem	O
is	O
deemed	O
to	O
be	O
an	O
important	O
part	O
in	O
OpenBSD	B-Operating_System
's	O
advocacy	O
for	O
open	O
hardware	O
documentation	O
,	O
and	O
the	O
3.8	O
release	O
title	O
and	O
the	O
titular	O
song	O
were	O
dedicated	O
to	O
the	O
topic	O
—	O
Hackers	O
of	O
the	O
Lost	O
RAID	B-Architecture
.	O
</s>
<s>
The	O
development	O
took	O
place	O
during	O
a	O
time	O
of	O
controversy	O
where	O
Adaptec	O
refused	O
to	O
release	O
appropriate	O
hardware	O
documentation	O
that	O
was	O
necessary	O
in	O
order	O
for	O
the	O
make	O
the	O
aac(4 )	O
driver	O
work	O
reliably	O
,	O
which	O
followed	O
with	O
OpenBSD	B-Operating_System
disabling	O
support	O
for	O
the	O
driver	O
.	O
</s>
<s>
In	O
the	O
commentary	O
to	O
the	O
3.8	O
release	O
,	O
the	O
developers	O
express	O
the	O
irony	B-Application
of	O
hardware	O
RAID	B-Device
controllers	I-Device
 '	O
supposed	O
purpose	O
of	O
providing	O
reliability	O
,	O
through	O
redundancy	O
and	O
repair	O
,	O
whereas	O
in	O
reality	O
many	O
vendors	O
expect	O
system	B-Application
administrators	I-Application
to	O
install	O
and	O
depend	O
on	O
huge	O
binary	O
blobs	O
in	O
order	O
to	O
be	O
assess	O
volume	O
health	O
and	O
service	O
their	O
disk	B-General_Concept
arrays	I-General_Concept
.	O
</s>
<s>
Specifically	O
,	O
OpenBSD	B-Operating_System
is	O
making	O
a	O
reference	O
to	O
the	O
modus	O
operandi	O
of	O
FreeBSD	B-Operating_System
,	O
where	O
the	O
documentation	O
of	O
the	O
aac(4 )	O
driver	O
for	O
Adaptec	O
specifically	O
suggests	O
enabling	O
Linux	O
compatibility	O
layer	O
in	O
order	O
to	O
use	O
the	O
management	O
utilities	O
(	O
where	O
the	O
documentation	O
even	O
fails	O
to	O
explain	O
where	O
exactly	O
these	O
utilities	O
must	O
be	O
obtained	O
from	O
,	O
or	O
which	O
versions	O
would	O
be	O
compatible	O
,	O
evidently	O
because	O
the	O
proprietary	B-Application
tools	I-Application
may	O
have	O
expired	O
)	O
.	O
</s>
<s>
Likewise	O
,	O
OpenBSD	B-Operating_System
developers	O
intentionally	O
chose	O
to	O
concentrate	O
on	O
supporting	O
only	O
the	O
most	O
basic	O
features	O
of	O
each	O
controller	O
which	O
are	O
uniform	O
across	O
all	O
the	O
brands	O
and	O
variations	O
;	O
specifically	O
,	O
the	O
fact	O
that	O
initial	O
configuration	O
of	O
each	O
controller	O
must	O
still	O
be	O
made	O
through	O
card	O
BIOS	B-Operating_System
was	O
never	O
kept	O
secret	O
from	O
any	O
bio/bioctl	O
announcement	O
.	O
</s>
<s>
This	O
can	O
be	O
contrasted	O
with	O
the	O
approach	O
taken	O
by	O
FreeBSD	B-Operating_System
,	O
for	O
example	O
,	O
where	O
individual	O
utilities	O
exist	O
for	O
several	O
independent	O
RAID	B-Architecture
drivers	O
,	O
and	O
the	O
interface	B-Application
of	O
each	O
utility	O
is	O
independent	O
of	O
one	O
another	O
;	O
specifically	O
,	O
,	O
FreeBSD	B-Operating_System
includes	O
separate	O
device-specific	O
utilities	O
called	O
mfiutil	O
,	O
mptutil	O
,	O
mpsutil/mprutil	O
and	O
sesutil	O
,,	O
each	O
of	O
which	O
provides	O
many	O
options	O
with	O
at	O
least	O
subtle	O
differences	O
in	O
the	O
interface	B-Application
for	O
configuration	O
and	O
management	O
of	O
the	O
controllers	O
,	O
contributes	O
to	O
code	O
bloat	O
,	O
not	O
to	O
mention	O
any	O
additional	O
drivers	O
for	O
which	O
no	O
such	O
tool	O
even	O
exists	O
as	O
open-source	B-Application
software	I-Application
at	O
all	O
.	O
</s>
<s>
In	O
OpenBSD	B-Operating_System
6.4	O
(	O
2018	O
)	O
,	O
a	O
dozen	O
of	O
drivers	O
register	O
with	O
the	O
bio	O
framework	O
.	O
</s>
<s>
Monitoring	O
of	O
the	O
state	O
of	O
each	O
logical	O
drive	O
is	O
also	O
duplicated	O
into	O
the	O
hardware	B-Application
monitoring	I-Application
frameworks	O
and	O
their	O
corresponding	O
utilities	O
on	O
both	O
systems	O
where	O
bioctl	O
is	O
available	O
—	O
hw.sensors	B-Application
with	O
sensorsd	B-Application
in	O
OpenBSD	B-Operating_System
and	O
sysmon	B-Device
envsys	I-Device
with	O
envstat	B-Device
and	O
powerd	O
in	O
NetBSD	B-Device
.	O
</s>
<s>
For	O
example	O
,	O
on	O
OpenBSD	B-Operating_System
since	O
4.2	O
release	O
,	O
the	O
status	O
of	O
the	O
drive	O
sensors	O
could	O
be	O
automatically	O
monitored	O
simply	O
by	O
starting	O
sensorsd	B-Application
without	O
any	O
specific	O
configuration	O
being	O
required	O
.	O
</s>
<s>
In	O
OpenBSD	B-Operating_System
,	O
both	O
SCSI	B-Application
Enclosure	I-Application
Services	I-Application
(	O
SES	O
)	O
and	O
SAF-TE	B-Application
are	O
supported	O
since	O
OpenBSD	B-Operating_System
3.8	O
(	O
2005	O
)	O
as	O
well	O
,	O
both	O
of	O
which	O
feature	O
LED	O
blinking	O
through	O
bio	O
and	O
bioctl	O
(	O
by	O
implementing	O
the	O
BIOCBLINK	O
ioctl	B-Operating_System
)	O
,	O
helping	O
system	B-Application
administrators	I-Application
identify	O
devices	O
within	O
the	O
enclosures	O
to	O
service	O
.	O
</s>
<s>
Additionally	O
,	O
both	O
the	O
SES	O
and	O
SAF-TE	B-Application
drivers	O
in	O
OpenBSD	B-Operating_System
feature	O
support	O
for	O
a	O
combination	O
of	O
temperature	O
and	O
fan	O
sensors	O
,	O
PSU	O
,	O
doorlock	O
and	O
alarm	O
indicators	O
;	O
all	O
of	O
this	O
auxiliary	O
sensor	O
data	O
is	O
exported	O
into	O
the	O
hw.sensors	B-Application
framework	O
in	O
OpenBSD	B-Operating_System
,	O
and	O
can	O
be	O
monitored	O
through	O
familiar	O
tools	O
like	O
sysctl	B-Application
,	O
SNMP	B-Protocol
and	O
sensorsd	B-Application
.	O
</s>
<s>
,	O
in	O
NetBSD	B-Device
,	O
an	O
older	O
SES/SAF	O
-TE	O
driver	O
from	O
NASA	O
from	O
2000	O
is	O
still	O
in	O
place	O
,	O
which	O
is	O
not	O
integrated	O
with	O
bio	O
or	O
envsys	B-Device
,	O
but	O
has	O
its	O
own	O
device	B-Application
files	I-Application
with	O
a	O
unique	O
ioctl	B-Operating_System
interface	B-Application
,	O
featuring	O
its	O
own	O
custom	O
SCSI-specific	O
userland	O
tooling	O
;	O
this	O
older	O
implementation	O
was	O
also	O
available	O
in	O
OpenBSD	B-Operating_System
between	O
2000	O
and	O
2005	O
,	O
and	O
was	O
removed	O
2005	O
(	O
together	O
with	O
its	O
userland	O
tools	O
)	O
just	O
before	O
the	O
new	O
leaner	O
bio	O
-	O
and	O
hw.sensors-based	O
alternative	O
drivers	O
were	O
introduced	O
;	O
SES	O
and	O
SAF-TE	B-Application
are	O
now	O
kept	O
as	O
two	O
separate	O
drivers	O
in	O
OpenBSD	B-Operating_System
,	O
but	O
do	O
n't	O
require	O
any	O
separate	O
custom	O
userland	O
utilities	O
anymore	O
,	O
reducing	O
the	O
code	O
bloat	O
and	O
the	O
number	O
of	O
source	O
lines	O
of	O
code	O
.	O
</s>
