<s>
A	O
system	B-Application
monitor	I-Application
is	O
a	O
hardware	B-Architecture
or	O
software	O
component	O
used	O
to	O
monitor	O
system	B-General_Concept
resources	I-General_Concept
and	O
performance	O
in	O
a	O
computer	O
system	O
.	O
</s>
<s>
Among	O
the	O
management	O
issues	O
regarding	O
use	O
of	O
system	B-Application
monitoring	I-Application
tools	O
are	O
resource	O
usage	O
and	O
privacy	O
.	O
</s>
<s>
These	O
monitoring	O
systems	O
are	O
often	O
used	O
to	O
keep	O
track	O
of	O
system	B-General_Concept
resources	I-General_Concept
,	O
such	O
as	O
CPU	B-General_Concept
usage	O
and	O
frequency	O
,	O
or	O
the	O
amount	O
of	O
free	O
RAM	B-Architecture
.	O
</s>
<s>
They	O
are	O
also	O
used	O
to	O
display	O
items	O
such	O
as	O
free	O
space	O
on	O
one	O
or	O
more	O
hard	O
drives	O
,	O
the	O
temperature	O
of	O
the	O
CPU	B-General_Concept
and	O
other	O
important	O
components	O
,	O
and	O
networking	O
information	O
including	O
the	O
system	O
IP	B-Protocol
address	I-Protocol
and	O
current	O
rates	O
of	O
upload	O
and	O
download	O
.	O
</s>
<s>
Other	O
possible	O
displays	O
may	O
include	O
the	O
date	O
and	O
time	O
,	O
system	B-Device
uptime	I-Device
,	O
computer	O
name	O
,	O
username	O
,	O
hard	O
drive	O
S.M.A.R.T.	O
</s>
<s>
data	O
,	O
fan	B-Application
speeds	O
,	O
and	O
the	O
voltages	O
being	O
provided	O
by	O
the	O
power	O
supply	O
.	O
</s>
<s>
Less	O
common	O
are	O
hardware-based	O
systems	O
monitoring	O
similar	O
information	O
.	O
</s>
<s>
Customarily	O
these	O
occupy	O
one	O
or	O
more	O
drive	B-Device
bays	I-Device
on	O
the	O
front	O
of	O
the	O
computer	B-General_Concept
case	I-General_Concept
,	O
and	O
either	O
interface	O
directly	O
with	O
the	O
system	O
hardware	B-Architecture
or	O
connect	O
to	O
a	O
software	O
data-collection	O
system	O
via	O
USB	B-Protocol
.	O
</s>
<s>
With	O
either	O
approach	O
to	O
gathering	O
data	O
,	O
the	O
monitoring	O
system	O
displays	O
information	O
on	O
a	O
small	O
LCD	B-Device
panel	I-Device
or	O
on	O
series	O
of	O
small	O
analog	O
or	O
LED	O
numeric	O
displays	O
.	O
</s>
<s>
Some	O
hardware-based	O
system	B-Application
monitors	I-Application
also	O
allow	O
direct	O
control	O
of	O
fan	B-Application
speeds	O
,	O
allowing	O
the	O
user	O
to	O
quickly	O
customize	O
the	O
cooling	O
in	O
the	O
system	O
.	O
</s>
<s>
A	O
few	O
very	O
high-end	O
models	O
of	O
hardware	B-Architecture
system	B-Application
monitor	I-Application
are	O
designed	O
to	O
interface	O
with	O
only	O
a	O
specific	O
model	O
of	O
motherboard	B-Device
.	O
</s>
<s>
Unlike	O
software	O
monitoring	O
tools	O
,	O
hardware	B-Architecture
measurement	O
tools	O
can	O
either	O
located	O
within	O
the	O
device	O
being	O
measure	O
,	O
or	O
they	O
can	O
be	O
attached	O
and	O
operate	O
from	O
an	O
external	O
location	O
.	O
</s>
<s>
A	O
hardware	B-Architecture
monitor	O
is	O
a	O
common	O
component	O
of	O
modern	O
motherboards	B-Device
,	O
which	O
can	O
either	O
come	O
as	O
a	O
separate	O
chip	O
,	O
often	O
interfaced	O
through	O
I2C	O
or	O
SMBus	B-Algorithm
,	O
or	O
as	O
part	O
of	O
a	O
Super	B-Device
I/O	I-Device
solution	O
,	O
often	O
interfaced	O
through	O
Low	O
Pin	O
Count	O
(	O
LPC	O
)	O
.	O
</s>
<s>
These	O
devices	O
make	O
it	O
possible	O
to	O
monitor	O
temperature	O
in	O
the	O
chassis	B-General_Concept
,	O
voltage	O
supplied	O
to	O
the	O
motherboard	B-Device
by	O
the	O
power	O
supply	O
unit	O
and	O
the	O
speed	O
of	O
the	O
computer	B-Application
fans	I-Application
that	O
are	O
connected	O
directly	O
to	O
one	O
of	O
the	O
fan	B-Application
headers	O
on	O
the	O
motherboard	B-Device
.	O
</s>
<s>
Many	O
of	O
these	O
hardware	B-Architecture
monitors	O
also	O
have	O
fan	B-Application
controlling	O
capabilities	O
.	O
</s>
<s>
System	B-Application
monitoring	I-Application
software	O
like	O
SpeedFan	B-Language
on	O
Windows	O
,	O
lm_sensors	O
on	O
Linux	O
,	O
envstat	B-Device
on	O
NetBSD	O
,	O
and	O
sysctl	O
hw.sensors	B-Application
on	O
OpenBSD	O
and	O
DragonFly	O
can	O
interface	O
with	O
these	O
chips	O
to	O
relay	O
this	O
environmental	O
sensor	O
information	O
to	O
the	O
user	O
.	O
</s>
<s>
When	O
an	O
individual	O
user	O
is	O
measuring	O
the	O
performance	O
of	O
a	O
single-user	B-Operating_System
system	O
,	O
whether	O
it	O
is	O
a	O
standalone	O
box	O
or	O
a	O
virtual	B-Architecture
machine	I-Architecture
on	O
a	O
multi-user	B-Operating_System
system	I-Operating_System
,	O
access	O
does	O
not	O
impede	O
the	O
privacy	O
of	O
others	O
.	O
</s>
<s>
Privacy	O
becomes	O
an	O
issue	O
when	O
someone	O
other	O
than	O
the	O
end-user	O
,	O
such	O
as	O
a	O
system	B-Application
manager	I-Application
,	O
has	O
legitimate	O
need	O
to	O
access	O
data	O
about	O
other	O
users	O
.	O
</s>
<s>
Another	O
consideration	O
is	O
not	O
having	O
major	O
impact	O
on	O
the	O
CPU	B-General_Concept
and	O
storage	O
available	O
for	O
useful	O
work	O
.	O
</s>
<s>
While	O
a	O
hardware	B-Architecture
monitor	O
will	O
usually	O
have	O
less	O
impact	O
than	O
a	O
software	O
monitor	O
,	O
there	O
are	O
data	O
items	O
,	O
such	O
as	O
"	O
some	O
descriptive	O
information	O
,	O
such	O
as	O
program	O
names	O
"	O
that	O
must	O
involve	O
software	O
.	O
</s>
<s>
A	O
further	O
consideration	O
is	O
that	O
a	O
bug	O
in	O
this	O
domain	O
can	O
have	O
severe	O
impact	O
:	O
an	O
extreme	O
case	O
would	O
be	O
"	O
cause	O
the	O
OS	O
to	O
crash.	O
"	O
</s>
