<s>
Sector/Sphere	B-General_Concept
is	O
an	O
open	B-Application
source	I-Application
software	I-Application
suite	O
for	O
high-performance	O
distributed	O
data	B-General_Concept
storage	I-General_Concept
and	O
processing	B-Architecture
.	O
</s>
<s>
It	O
can	O
be	O
broadly	O
compared	O
to	O
Google	B-Application
's	I-Application
GFS	B-Application
and	O
MapReduce	B-Operating_System
technology	O
.	O
</s>
<s>
Sector	O
is	O
a	O
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
targeting	O
data	B-General_Concept
storage	I-General_Concept
over	O
a	O
large	O
number	O
of	O
commodity	O
computers	O
.	O
</s>
<s>
Sphere	O
is	O
the	O
programming	O
architecture	B-Architecture
framework	I-Architecture
that	O
supports	O
in-storage	O
parallel	O
data	O
processing	B-Architecture
for	O
data	O
stored	O
in	O
Sector	O
.	O
</s>
<s>
Sector/Sphere	B-General_Concept
operates	O
in	O
a	O
wide	O
area	O
network	O
(	O
WAN	O
)	O
setting	O
.	O
</s>
<s>
The	O
system	O
was	O
created	O
by	O
Yunhong	O
Gu	O
(	O
the	O
author	O
of	O
UDP-based	B-Language
Data	I-Language
Transfer	I-Language
Protocol	I-Language
)	O
in	O
2006	O
and	O
was	O
then	O
maintained	O
by	O
a	O
group	O
of	O
other	O
developers	O
.	O
</s>
<s>
Sector/Sphere	B-General_Concept
consists	O
of	O
four	O
components	O
.	O
</s>
<s>
The	O
clients	O
are	O
the	O
users	O
 '	O
computers	O
from	O
which	O
system	O
access	O
and	O
data	O
processing	B-Architecture
requests	O
are	O
issued	O
.	O
</s>
<s>
Also	O
,	O
Sector/Sphere	B-General_Concept
is	O
written	O
in	O
C++	B-Language
and	O
is	O
claimed	O
to	O
achieve	O
with	O
its	O
architecture	O
a	O
two	O
to	O
four	O
times	O
better	O
performance	O
than	O
the	O
competitor	O
Hadoop	B-Application
which	O
is	O
written	O
in	O
Java	B-Language
,	O
a	O
statement	O
supported	O
by	O
an	O
Aster	O
Data	O
Systems	O
benchmark	O
and	O
the	O
winning	O
of	O
the	O
"	O
bandwidth	O
challenge	O
"	O
of	O
the	O
Supercomputing	O
Conference	O
2006	O
,	O
2008	O
,	O
and	O
2009	O
.	O
</s>
<s>
Sector	O
provides	O
file	O
system-level	O
fault	O
tolerance	O
by	O
replication	O
,	O
thus	O
it	O
does	O
not	O
require	O
hardware	O
fault	O
tolerance	O
such	O
as	O
RAID	B-Architecture
,	O
which	O
is	O
usually	O
very	O
expensive	O
.	O
</s>
<s>
The	O
advantages	O
,	O
however	O
,	O
are	O
that	O
the	O
Sector	O
file	O
system	O
is	O
very	O
simple	O
,	O
and	O
it	O
leads	O
to	O
better	O
performance	O
in	O
Sphere	O
parallel	O
data	O
processing	B-Architecture
due	O
to	O
reduced	O
data	O
transfer	O
between	O
nodes	O
.	O
</s>
<s>
The	O
topology	O
awareness	O
and	O
the	O
use	O
of	O
UDT	B-Language
as	O
data	O
transfer	O
protocol	O
allows	O
Sector	O
to	O
support	O
high	O
performance	O
data	O
IO	O
across	O
geographically	O
distributed	O
locations	O
,	O
while	O
most	O
file	O
systems	O
can	O
only	O
be	O
deployed	O
within	O
a	O
local	O
area	O
network	O
.	O
</s>
<s>
Sector	O
integrates	O
data	B-General_Concept
storage	I-General_Concept
and	O
processing	B-Architecture
into	O
one	O
system	O
.	O
</s>
<s>
Every	O
storage	O
node	O
can	O
also	O
be	O
used	O
to	O
process	O
the	O
data	O
,	O
thus	O
it	O
can	O
support	O
massive	O
in-storage	O
parallel	O
data	O
processing	B-Architecture
(	O
see	O
Sphere	O
)	O
.	O
</s>
<s>
The	O
Sector	O
client	O
provides	O
an	O
API	B-General_Concept
for	O
application	O
development	O
which	O
allows	O
user	O
applications	O
to	O
interact	O
directly	O
with	O
Sector	O
.	O
</s>
<s>
Finally	O
,	O
Sector	O
supports	O
the	O
FUSE	B-Application
interface	O
;	O
presenting	O
a	O
mountable	O
file	O
system	O
that	O
is	O
accessible	O
via	O
standard	O
command-line	O
tools	O
.	O
</s>
<s>
Sphere	O
is	O
a	O
parallel	O
data	O
processing	B-Architecture
engine	O
integrated	O
in	O
Sector	O
and	O
it	O
can	O
be	O
used	O
to	O
process	O
data	O
stored	O
in	O
Sector	O
in	O
parallel	O
.	O
</s>
<s>
It	O
can	O
broadly	O
compared	O
to	O
MapReduce	B-Operating_System
,	O
but	O
it	O
uses	O
generic	O
user	O
defined	O
functions	O
(	O
UDFs	O
)	O
instead	O
of	O
the	O
map	O
and	O
reduce	O
functions	O
.	O
</s>
