<s>
RRDtool	B-Language
(	O
round-robin	B-Language
database	I-Language
tool	O
)	O
aims	O
to	O
handle	O
time	O
series	O
data	O
such	O
as	O
network	B-Architecture
bandwidth	O
,	O
temperatures	O
or	O
CPU	B-General_Concept
load	O
.	O
</s>
<s>
The	O
data	O
is	O
stored	O
in	O
a	O
circular	B-Data_Structure
buffer	I-Data_Structure
based	O
database	O
,	O
thus	O
the	O
system	O
storage	O
footprint	O
remains	O
constant	O
over	O
time	O
.	O
</s>
<s>
Perl	B-Language
,	O
Python	B-Language
,	O
Ruby	B-Language
,	O
Tcl	B-Operating_System
,	O
PHP	B-Application
and	O
Lua	B-Language
.	O
</s>
<s>
There	O
is	O
an	O
independent	O
full	O
Java	B-Language
implementation	O
called	O
rrd4j	O
.	O
</s>
<s>
RRDtool	B-Language
assumes	O
time-variable	O
data	O
in	O
intervals	O
of	O
a	O
certain	O
length	O
.	O
</s>
<s>
Because	O
data	O
may	O
not	O
always	O
be	O
available	O
at	O
just	O
the	O
right	O
time	O
,	O
RRDtool	B-Language
will	O
automatically	O
interpolate	O
any	O
submitted	O
data	O
to	O
fit	O
its	O
internal	O
time-steps	O
.	O
</s>
<s>
The	O
data	O
retrieval	O
function	O
of	O
RRDtool	B-Language
automatically	O
selects	O
the	O
archive	O
with	O
the	O
highest	O
resolution	O
that	O
still	O
covers	O
the	O
requested	O
timespan	O
.	O
</s>
<s>
This	O
mechanism	O
is	O
also	O
used	O
by	O
RRDtool	B-Language
's	O
graphing	O
subsystem	O
.	O
</s>
<s>
The	O
following	O
table	O
contains	O
the	O
release	O
history	O
of	O
RRDtool	B-Language
,	O
showing	O
its	O
major	O
releases	O
.	O
</s>
<s>
Basically	O
MRTG	B-Protocol
"	O
done	O
right	O
"	O
.	O
</s>
