<s>
In	O
computer	O
storage	B-General_Concept
,	O
SAF-TE	B-Application
(	O
abbreviated	O
from	O
SCSI	B-Application
Accessed	I-Application
Fault-Tolerant	I-Application
Enclosure	I-Application
)	O
is	O
an	O
industry	O
standard	O
to	O
interface	O
an	O
enclosure	B-Device
in-band	O
to	O
a	O
(	O
parallel	O
)	O
SCSI	B-Architecture
subsystem	O
in	O
order	O
to	O
gain	O
access	O
to	O
information	O
or	O
control	O
for	O
various	O
elements	O
and	O
parameters	O
.	O
</s>
<s>
LEDs	O
,	O
LCDs	B-Device
)	O
.	O
</s>
<s>
Practically	O
,	O
any	O
given	O
SAF-TE	B-Application
device	O
will	O
only	O
support	O
a	O
subset	O
of	O
all	O
possible	O
sensors	O
or	O
controls	O
.	O
</s>
<s>
Many	O
RAID	B-Architecture
controllers	O
can	O
utilize	O
a	O
SAF-TE	B-Application
"	O
activated	O
"	O
backplane	B-Architecture
by	O
detecting	O
a	O
swapped	O
drive	O
(	O
after	O
a	O
defect	O
)	O
and	O
automatically	O
starting	O
a	O
rebuild	O
.	O
</s>
<s>
A	O
SAF-TE	B-Application
device	O
(	O
SEP	O
)	O
is	O
represented	O
as	O
a	O
SCSI	B-Architecture
processor	O
device	O
that	O
is	O
polled	O
every	O
few	O
seconds	O
by	O
e.g.	O
</s>
<s>
the	O
RAID	B-Architecture
controller	O
software	O
.	O
</s>
<s>
For	O
SAS	O
or	O
Fibre	B-Architecture
Channel	I-Architecture
systems	O
,	O
SAF-TE	B-Application
is	O
replaced	O
by	O
the	O
more	O
standardized	O
SCSI	B-Application
Enclosure	I-Application
Services	I-Application
(	O
SES	O
)	O
.	O
</s>
<s>
The	O
most	O
widely	O
used	O
version	O
was	O
defined	O
in	O
the	O
SAF-TE	B-Application
Interface	O
Specification	O
Intermediate	O
Review	O
R041497	O
,	O
released	O
on	O
April	O
14	O
,	O
1997	O
by	O
nStor	O
(	O
now	O
part	O
of	O
Seagate	O
Technology	O
)	O
and	O
Intel	O
.	O
</s>
<s>
Status	O
requests	O
are	O
performed	O
as	O
READ	O
BUFFER	O
SCSI	B-Architecture
commands	O
,	O
enclosure	B-Device
action	O
requests	O
as	O
WRITE	O
BUFFER	O
commands	O
.	O
</s>
<s>
Command	O
type	O
Opcode	O
mandatory	O
/	O
optional	O
Command	O
Description	O
READ	O
BUFFER	O
00h	O
m	O
Read	O
enclosure	B-Device
configuration	O
inquire	O
about	O
system	O
components	O
in	O
the	O
enclosure	B-Device
01h	O
m	O
Read	O
enclosure	B-Device
status	O
inquire	O
about	O
operational	O
status	O
of	O
enclosure	B-Device
components	O
02h	O
o	O
Read	O
usage	O
statistics	O
fetch	O
information	O
about	O
total	O
usage	O
time	O
and	O
number	O
of	O
power-cycles	O
03h	O
o	O
Read	O
device	O
insertions	O
returns	O
information	O
on	O
how	O
many	O
times	O
a	O
device	O
has	O
been	O
inserted	O
into	O
each	O
enclosure	B-Device
slot	O
04h	O
m	O
Read	O
device	O
slot	O
status	O
returns	O
information	O
on	O
the	O
current	O
state	O
of	O
each	O
slot	O
05h	O
o	O
Read	O
global	O
flags	O
read	O
global	O
flags	O
from	O
processor	O
WRITE	O
BUFFER	O
10h	O
m	O
Write	O
device	O
slot	O
status	O
updates	O
state	O
of	O
the	O
slots	O
,	O
essentially	O
drives	O
LEDs	O
,	O
alarms	O
etc	O
.	O
</s>
