<s>
The	O
Hardware	B-Application
Platform	I-Application
Interface	I-Application
(	O
HPI	O
)	O
is	O
an	O
open	O
specification	O
that	O
defines	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
for	O
platform	O
management	O
of	O
computer	O
systems	O
.	O
</s>
<s>
The	O
API	B-Application
supports	O
tasks	O
including	O
reading	O
temperature	O
or	O
voltage	O
sensors	O
built	O
into	O
a	O
processor	O
,	O
configuring	O
hardware	O
registers	O
,	O
accessing	O
system	O
inventory	O
information	O
like	O
model	O
numbers	O
and	O
serial	O
numbers	O
,	O
and	O
performing	O
more	O
complex	O
activities	O
,	O
such	O
as	O
upgrading	O
system	O
firmware	B-Application
or	O
diagnosing	O
system	O
failures	O
.	O
</s>
<s>
HPI	O
is	O
designed	O
for	O
use	O
with	O
fault-tolerant	B-General_Concept
and	O
modular	O
high-availability	B-General_Concept
computer	O
systems	O
,	O
which	O
typically	O
include	O
automatic	O
fault	O
detection	O
features	O
and	O
hardware	O
redundancy	O
so	O
that	O
they	O
can	O
provide	O
continuous	O
Service	O
Availability	O
.	O
</s>
<s>
Additional	O
features	O
common	O
in	O
hardware	O
platforms	O
used	O
for	O
high-availability	B-General_Concept
applications	O
include	O
online	O
serviceability	O
and	O
upgradeability	O
via	O
hot-swappable	B-Device
modules	O
.	O
</s>
<s>
The	O
need	O
for	O
the	O
HPI	O
specification	O
was	O
first	O
identified	O
by	O
an	O
industry	O
group	O
called	O
the	O
“	O
High	O
Availability	O
Forum	O
,	O
”	O
which	O
met	O
for	O
several	O
months	O
in	O
2000	O
to	O
discuss	O
issues	O
relating	O
to	O
building	O
high-availability	B-General_Concept
computer	O
systems	O
using	O
open	B-Architecture
architecture	I-Architecture
technology	O
.	O
</s>
<s>
Growing	O
out	O
of	O
that	O
work	O
,	O
Intel	O
Corporation	O
began	O
a	O
project	O
to	O
define	O
a	O
standard	O
hardware	O
platform	O
management	O
API	B-Application
named	O
the	O
Universal	O
Chassis	O
Management	O
Interface	O
(	O
UCMI	O
)	O
.	O
</s>
<s>
This	O
work	O
was	O
migrated	O
to	O
the	O
newly	O
formed	O
SA	O
Forum	O
consortium	O
and	O
was	O
published	O
as	O
the	O
Hardware	B-Application
Platform	I-Application
Interface	I-Application
in	O
October	O
2002	O
.	O
</s>
<s>
Additionally	O
,	O
specifications	O
for	O
accessing	O
an	O
HPI	O
implementation	O
via	O
Simple	O
Network	O
Management	O
Protocol(SNMP )	O
and	O
specifications	O
describing	O
the	O
use	O
of	O
HPI	O
on	O
AdvancedTCA	O
and	O
MicroTCA	O
platforms	O
have	O
been	O
produced	O
.	O
</s>
<s>
Addressed	O
implementation	O
and	O
usability	O
issues	O
in	O
original	O
specification	O
SAI-HPI-SNMP-B.01.01	O
May	O
3	O
,	O
2004	O
SNMP	B-Protocol
MIB	O
for	O
accessing	O
HPI	O
implementations	O
SAI-HPI-B.02.01	O
January	O
18	O
,	O
2006	O
Minor	O
revision	O
to	O
the	O
base	O
HPI	O
specification	O
.	O
</s>
<s>
Enhancements	O
to	O
FUMI	O
;	O
some	O
new	O
API	B-Application
functions	I-Application
SAI-HPI-B.03.02	O
November	O
20	O
,	O
2009	O
Minor	O
corrections	O
to	O
the	O
base	O
HPI	O
specification	O
SAIM-HPI-B.03.02-xTCA	O
February	O
19	O
,	O
2010	O
Major	O
revision	O
to	O
the	O
AdvancedTCA	O
mapping	O
specification	O
.	O
</s>
<s>
The	O
AIS	O
specifications	O
can	O
be	O
implemented	O
and	O
used	O
for	O
high-availability	B-General_Concept
clustering	O
middleware	O
that	O
does	O
not	O
implement	O
hardware	O
platform	O
management	O
,	O
and	O
the	O
HPI	O
specification	O
can	O
be	O
implemented	O
by	O
platform	O
providers	O
and	O
used	O
directly	O
by	O
application	O
or	O
management	O
programs	O
without	O
the	O
use	O
of	O
other	O
SA	O
Forum	O
management	O
middleware	O
.	O
</s>
<s>
The	O
Management	O
Instruments	O
abstract	O
management	O
components	O
built	O
into	O
the	O
platform	O
,	O
like	O
temperature	O
or	O
voltage	O
sensors	O
,	O
configuration	O
registers	O
and	O
display	O
elements	O
,	O
or	O
provide	O
interfaces	O
to	O
management	O
functions	O
,	O
such	O
as	O
upgrading	O
firmware	B-Application
and	O
running	O
diagnostics	O
.	O
</s>
<s>
The	O
first	O
four	O
:	O
Sensors	O
,	O
Controls	O
,	O
Inventory	O
Data	O
Repositories	O
and	O
Watchdog	B-Application
Timers	I-Application
,	O
are	O
basic	O
Management	O
Instruments	O
that	O
usually	O
map	O
to	O
discrete	O
platform	O
management	O
capabilities	O
.	O
</s>
<s>
Typically	O
,	O
items	O
like	O
model	O
number	O
,	O
serial	O
number	O
and	O
basic	O
configuration	O
data	O
are	O
stored	O
in	O
ROM	B-Device
or	O
flash	B-Device
memory	I-Device
on	O
a	O
hardware	O
entity	O
.	O
</s>
<s>
Watchdog	B-Application
Timers	I-Application
are	O
devices	O
that	O
are	O
often	O
implemented	O
with	O
special	O
hardware	O
in	O
high	O
availability	O
systems	O
.	O
</s>
<s>
The	O
purpose	O
of	O
a	O
watchdog	B-Application
timer	I-Application
device	O
is	O
to	O
provide	O
a	O
fault-detection	O
mechanism	O
.	O
</s>
<s>
The	O
HPI	O
Watchdog	B-Application
Timer	I-Application
Management	O
Instrument	O
is	O
designed	O
to	O
interface	O
with	O
this	O
sort	O
of	O
hardware	O
mechanism	O
.	O
</s>
<s>
It	O
is	O
modeled	O
very	O
closely	O
on	O
the	O
IPMI	O
watchdog	B-Application
timer	I-Application
.	O
</s>
<s>
DIMIs	O
are	O
logical	O
management	O
instruments	O
used	O
to	O
coordinate	O
the	O
running	O
of	O
on-line	O
or	O
off-line	O
diagnostic	O
firmware	B-Application
or	O
software	O
on	O
various	O
hardware	O
entities	O
.	O
</s>
<s>
FUMIs	O
are	O
logical	O
management	O
instruments	O
that	O
are	O
used	O
to	O
support	O
the	O
installation	O
of	O
firmware	B-Application
updates	O
to	O
programmable	O
hardware	O
Entities	O
.	O
</s>
<s>
For	O
hardware	O
Entities	O
that	O
include	O
field-upgradeable	O
firmware	B-Application
,	O
the	O
FUMI	O
provides	O
information	O
on	O
the	O
currently	O
installed	O
firmware	B-Application
version(s )	O
,	O
and	O
provides	O
a	O
standard	O
interface	O
for	O
identifying	O
a	O
new	O
version	O
to	O
load	O
,	O
and	O
to	O
coordinate	O
the	O
upgrade	O
process	O
,	O
including	O
possible	O
backup	O
,	O
and	O
rollback	O
to	O
previous	O
versions	O
,	O
if	O
required	O
.	O
</s>
<s>
A	O
key	O
feature	O
of	O
the	O
HPI	O
specification	O
is	O
the	O
way	O
it	O
handles	O
dynamic	O
reconfiguration	O
,	O
or	O
hot-swap	B-Device
actions	O
in	O
the	O
managed	O
platform	O
.	O
</s>
<s>
Hot-swap	B-Device
refers	O
to	O
the	O
ability	O
to	O
add	O
or	O
remove	O
hardware	O
components	O
in	O
a	O
running	O
platform	O
.	O
</s>
<s>
Thus	O
,	O
hot-swapping	B-Device
a	O
FRU	O
can	O
simultaneously	O
modify	O
both	O
the	O
set	O
of	O
hardware	O
Entities	O
to	O
be	O
managed	O
and	O
the	O
infrastructure	O
available	O
for	O
that	O
management	O
.	O
</s>
<s>
The	O
HPI	O
approach	O
to	O
hot-swap	B-Device
management	O
reflects	O
this	O
by	O
modeling	O
the	O
addition	O
or	O
removal	O
of	O
a	O
hardware	O
Entity	O
by	O
adding	O
or	O
removing	O
a	O
Resource	O
in	O
a	O
Domain	O
.	O
</s>
<s>
The	O
Resource	O
associated	O
with	O
a	O
FRU	O
will	O
always	O
be	O
in	O
one	O
of	O
five	O
Hot-swap	B-Device
States	O
,	O
which	O
are	O
readable	O
by	O
the	O
HPI	O
user	O
:	O
Not	O
Present	O
,	O
Inactive	O
,	O
Insertion	O
Pending	O
,	O
Active	O
,	O
Extraction	O
Pending	O
.	O
</s>
<s>
When	O
a	O
Resource	O
changes	O
to	O
a	O
new	O
Hot-swap	B-Device
State	O
,	O
an	O
HPI	O
event	O
is	O
sent	O
to	O
user	O
programs	O
that	O
have	O
requested	O
event	O
notifications	O
.	O
</s>
<s>
HPI	O
Resources	O
that	O
model	O
hot-swappable	B-Device
FRUs	O
may	O
be	O
configured	O
to	O
support	O
either	O
Unmanaged	O
Hot-swap	B-Device
or	O
Managed	O
Hot-swap	B-Device
.	O
</s>
<s>
A	O
Resource	O
that	O
supports	O
Unmanaged	O
Hot-swap	B-Device
will	O
report	O
its	O
current	O
Hot-swap	B-Device
State	O
,	O
but	O
the	O
user	O
has	O
no	O
control	O
over	O
the	O
Hot-swap	B-Device
operations	O
of	O
the	O
FRU	O
.	O
</s>
<s>
When	O
a	O
Resource	O
supports	O
Managed	O
Hot-swap	B-Device
,	O
then	O
a	O
user	O
program	O
can	O
interact	O
with	O
the	O
HPI	O
implementation	O
and	O
the	O
underlying	O
platform	O
management	O
infrastructure	O
to	O
coordinate	O
the	O
actions	O
required	O
to	O
integrate	O
newly	O
added	O
FRUs	O
or	O
to	O
deactivate	O
FRUs	O
being	O
removed	O
from	O
the	O
system	O
.	O
</s>
<s>
It	O
is	O
a	O
goal	O
of	O
the	O
SA	O
Forum	O
that	O
new	O
versions	O
of	O
its	O
specifications	O
be	O
kept	O
backward	B-General_Concept
compatible	I-General_Concept
with	O
previous	O
versions	O
.	O
</s>
<s>
The	O
“	O
B	O
”	O
series	O
of	O
HPI	O
specifications	O
are	O
not	O
backward	B-General_Concept
compatible	I-General_Concept
with	O
the	O
SAI-HPI-A.01.01	O
specification	O
.	O
</s>
<s>
To	O
achieve	O
backward	B-General_Concept
compatibility	I-General_Concept
of	O
HPI	O
specifications	O
,	O
several	O
strategies	O
are	O
employed	O
:	O
</s>
<s>
Several	O
widely	O
deployed	O
implementations	O
of	O
the	O
HPI	O
specification	O
have	O
been	O
produced	O
,	O
most	O
notably	O
by	O
platform	O
vendors	O
that	O
build	O
AdvancedTCA	O
computer	O
systems	O
or	O
other	O
high-availability	B-General_Concept
computer	O
platforms	O
.	O
</s>
<s>
In	O
most	O
implementations	O
the	O
HPI	O
Application	B-Application
Program	I-Application
Interface	I-Application
itself	O
is	O
provided	O
through	O
a	O
library	O
that	O
is	O
linked	O
to	O
application	O
programs	O
.	O
</s>
<s>
This	O
library	O
module	O
typically	O
communicates	O
to	O
an	O
HPI	O
Server	O
running	O
as	O
a	O
daemon	B-Operating_System
process	I-Operating_System
,	O
which	O
performs	O
the	O
functions	O
of	O
the	O
HPI	O
Domains	O
and	O
Resources	O
,	O
communicating	O
with	O
an	O
underlying	O
management	O
infrastructure	O
as	O
required	O
.	O
</s>
<s>
Several	O
HPI	O
implementations	O
are	O
based	O
on	O
an	O
open-source	B-License
implementation	O
of	O
the	O
HPI	O
specification	O
,	O
called	O
.	O
</s>
<s>
OpenHPI	B-Language
also	O
follows	O
the	O
general	O
design	O
shown	O
in	O
Figure	O
6	O
,	O
in	O
that	O
it	O
includes	O
a	O
library	O
module	O
that	O
links	O
with	O
application	O
programs	O
and	O
a	O
daemon	B-Operating_System
module	O
to	O
which	O
the	O
library	O
modules	O
communicate	O
.	O
</s>
<s>
The	O
OpenHPI	B-Language
daemon	B-Operating_System
process	I-Operating_System
is	O
designed	O
to	O
integrate	O
with	O
one	O
or	O
more	O
plug-in	B-Application
modules	I-Application
,	O
which	O
handle	O
the	O
downstream	O
communication	O
with	O
various	O
platform	O
management	O
infrastructures	O
.	O
</s>
