<s>
Volunteer	B-Operating_System
computing	I-Operating_System
is	O
a	O
type	O
of	O
distributed	B-Architecture
computing	I-Architecture
in	O
which	O
people	O
donate	O
their	O
computers	O
 '	O
unused	O
resources	O
to	O
a	O
research-oriented	O
project	O
,	O
and	O
sometimes	O
in	O
exchange	O
for	O
credit	O
points	O
.	O
</s>
<s>
Common	O
tasks	O
such	O
as	O
word	B-General_Concept
processing	I-General_Concept
or	O
web	O
browsing	O
leave	O
the	O
computer	O
mostly	O
idle	O
.	O
</s>
<s>
The	O
practice	O
of	O
volunteer	B-Operating_System
computing	I-Operating_System
,	O
which	O
dates	O
back	O
to	O
the	O
mid-1990s	O
,	O
can	O
potentially	O
make	O
substantial	O
processing	O
power	O
available	O
to	O
researchers	O
at	O
minimal	O
cost	O
.	O
</s>
<s>
A	O
middleware	B-General_Concept
system	O
usually	O
serves	O
as	O
an	O
intermediary	O
.	O
</s>
<s>
The	O
first	O
volunteer	B-Operating_System
computing	I-Operating_System
project	O
was	O
the	O
Great	O
Internet	O
Mersenne	O
Prime	O
Search	O
,	O
which	O
started	O
in	O
January	O
1996	O
.	O
</s>
<s>
In	O
1997	O
and	O
1998	O
,	O
several	O
academic	O
research	O
projects	O
developed	O
Java-based	O
systems	O
for	O
volunteer	B-Operating_System
computing	I-Operating_System
;	O
examples	O
include	O
Bayanihan	O
,	O
Popcorn	O
,	O
Superweb	O
,	O
and	O
Charlotte	O
.	O
</s>
<s>
The	O
term	O
volunteer	B-Operating_System
computing	I-Operating_System
was	O
coined	O
by	O
Luis	O
F	O
.	O
G	O
.	O
Sarmenta	O
,	O
the	O
developer	O
of	O
Bayanihan	O
.	O
</s>
<s>
In	O
1999	O
,	O
the	O
SETI	B-Application
@home	I-Application
and	O
Folding	B-Application
@home	I-Application
projects	O
were	O
launched	O
.	O
</s>
<s>
Between	O
1998	O
and	O
2002	O
,	O
several	O
companies	O
were	O
formed	O
with	O
business	O
models	O
involving	O
volunteer	B-Operating_System
computing	I-Operating_System
.	O
</s>
<s>
Examples	O
include	O
Popular	O
Power	O
,	O
Porivo	O
,	O
Entropia	O
,	O
and	O
United	B-Operating_System
Devices	I-Operating_System
.	O
</s>
<s>
In	O
2002	O
,	O
the	O
Berkeley	B-Operating_System
Open	I-Operating_System
Infrastructure	I-Operating_System
for	I-Operating_System
Network	I-Operating_System
Computing	I-Operating_System
(	O
BOINC	B-Operating_System
)	O
project	O
was	O
founded	O
at	O
University	O
of	O
California	O
,	O
Berkeley	O
Space	O
Sciences	O
Laboratory	O
,	O
funded	O
by	O
the	O
National	O
Science	O
Foundation	O
.	O
</s>
<s>
BOINC	B-Operating_System
provides	O
a	O
complete	O
middleware	B-General_Concept
system	O
for	O
volunteer	B-Operating_System
computing	I-Operating_System
,	O
including	O
a	O
client	O
,	O
client	O
GUI	O
,	O
application	O
runtime	O
system	O
,	O
server	O
software	O
,	O
and	O
software	O
implementing	O
a	O
project	O
web	O
site	O
.	O
</s>
<s>
The	O
first	O
project	O
based	O
on	O
BOINC	B-Operating_System
was	O
Predictor	B-Operating_System
@home	I-Operating_System
,	O
based	O
at	O
the	O
Scripps	O
Research	O
Institute	O
,	O
which	O
began	O
operation	O
in	O
2004	O
.	O
</s>
<s>
Soon	O
thereafter	O
,	O
SETI	B-Application
@home	I-Application
and	O
climateprediction.net	B-Operating_System
began	O
using	O
BOINC	B-Operating_System
.	O
</s>
<s>
A	O
number	O
of	O
new	O
BOINC-based	O
projects	O
were	O
created	O
over	O
the	O
next	O
few	O
years	O
,	O
including	O
Rosetta	B-Operating_System
@home	I-Operating_System
,	O
Einstein	B-Operating_System
@home	I-Operating_System
,	O
and	O
AQUA	B-Operating_System
@home	I-Operating_System
.	O
</s>
<s>
In	O
2007	O
,	O
IBM	O
World	B-Operating_System
Community	I-Operating_System
Grid	I-Operating_System
switched	O
from	O
the	O
United	B-Operating_System
Devices	I-Operating_System
platform	O
to	O
BOINC	B-Operating_System
.	O
</s>
<s>
The	O
client	O
software	O
of	O
the	O
early	O
volunteer	B-Operating_System
computing	I-Operating_System
projects	O
consisted	O
of	O
a	O
single	O
program	O
that	O
combined	O
the	O
scientific	O
computation	O
and	O
the	O
distributed	B-Architecture
computing	I-Architecture
infrastructure	O
.	O
</s>
<s>
More	O
recently	O
,	O
volunteer	B-Operating_System
computing	I-Operating_System
has	O
moved	O
to	O
middleware	B-General_Concept
systems	O
that	O
provide	O
a	O
distributed	B-Architecture
computing	I-Architecture
infrastructure	O
independent	O
from	O
the	O
scientific	O
computation	O
.	O
</s>
<s>
BOINC	B-Operating_System
is	O
the	O
most	O
widely	O
used	O
middleware	B-General_Concept
system	O
.	O
</s>
<s>
Xgrid	B-Operating_System
is	O
developed	O
by	O
Apple	O
.	O
</s>
<s>
Grid	B-Operating_System
MP	I-Operating_System
is	O
a	O
commercial	O
middleware	B-General_Concept
platform	O
developed	O
by	O
United	B-Operating_System
Devices	I-Operating_System
and	O
was	O
used	O
in	O
volunteer	B-Operating_System
computing	I-Operating_System
projects	O
including	O
grid.org,	O
World	B-Operating_System
Community	I-Operating_System
Grid	I-Operating_System
,	O
Cell	B-Operating_System
Computing	I-Operating_System
,	O
and	O
Hikari	O
Grid	O
.	O
</s>
<s>
Volunteer	B-Operating_System
computing	I-Operating_System
systems	O
must	O
deal	O
with	O
several	O
issues	O
involving	O
volunteered	O
computers	O
:	O
their	O
heterogeneity	O
,	O
their	O
churn	O
(	O
the	O
tendency	O
of	O
individual	O
computers	O
to	O
join	O
and	O
leave	O
the	O
network	O
over	O
time	O
)	O
,	O
their	O
sporadic	O
availability	O
,	O
and	O
the	O
need	O
to	O
not	O
interfere	O
with	O
their	O
performance	O
during	O
regular	O
use	O
.	O
</s>
<s>
In	O
addition	O
,	O
volunteer	B-Operating_System
computing	I-Operating_System
systems	O
must	O
deal	O
with	O
problems	O
related	O
to	O
correctness	O
:	O
</s>
<s>
Decreased	O
performance	O
of	O
the	O
PC	O
:	O
If	O
the	O
volunteer	B-Operating_System
computing	I-Operating_System
application	O
runs	O
while	O
the	O
computer	O
is	O
in	O
use	O
,	O
it	O
may	O
impact	O
performance	O
of	O
the	O
PC	O
.	O
</s>
<s>
Volunteer	B-Operating_System
computing	I-Operating_System
applications	O
typically	O
execute	O
at	O
a	O
lower	O
CPU	O
scheduling	O
priority	O
,	O
which	O
helps	O
to	O
alleviate	O
CPU	O
contention	O
.	O
</s>
<s>
Volunteer	B-Operating_System
computing	I-Operating_System
can	O
provide	O
researchers	O
with	O
computing	O
power	O
that	O
is	O
not	O
achievable	O
any	O
other	O
way	O
.	O
</s>
<s>
For	O
example	O
,	O
Folding	B-Application
@home	I-Application
has	O
been	O
ranked	O
as	O
one	O
of	O
the	O
world	O
's	O
fastest	O
computing	O
systems	O
.	O
</s>
<s>
With	O
heightened	O
interest	O
and	O
volunteer	O
participation	O
in	O
the	O
project	O
as	O
a	O
result	O
of	O
the	O
COVID-19	O
pandemic	O
,	O
the	O
system	O
achieved	O
a	O
speed	O
of	O
approximately	O
1.22	O
exaflops	O
by	O
late	O
March	O
2020	O
and	O
reached	O
2.43	O
exaflops	O
by	O
April	O
12	O
,	O
2020	O
,	O
making	O
it	O
the	O
world	O
's	O
first	O
exaflop	B-General_Concept
computing	I-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Volunteer	B-Operating_System
computing	I-Operating_System
is	O
often	O
cheaper	O
than	O
other	O
forms	O
of	O
distributed	B-Architecture
computing	I-Architecture
,	O
and	O
typically	O
at	O
zero	O
cost	O
to	O
the	O
end	O
researcher	O
.	O
</s>
<s>
Although	O
there	O
are	O
issues	O
such	O
as	O
lack	O
of	O
accountability	O
and	O
trust	O
between	O
participants	O
and	O
researchers	O
while	O
implementing	O
the	O
projects	O
,	O
volunteer	B-Operating_System
computing	I-Operating_System
is	O
crucially	O
important	O
,	O
especially	O
to	O
projects	O
that	O
have	O
limited	O
funding	O
.	O
</s>
<s>
Whereas	O
volunteer	B-Operating_System
computing	I-Operating_System
is	O
not	O
something	O
that	O
can	O
be	O
bought	O
,	O
its	O
power	O
arises	O
from	O
the	O
public	O
support	O
.	O
</s>
