<s>
SETI	B-Application
@home	I-Application
(	O
"	O
SETI	B-Application
at	I-Application
home	I-Application
"	O
)	O
is	O
a	O
project	O
of	O
the	O
Berkeley	O
SETI	O
Research	O
Center	O
to	O
analyze	O
radio	O
signals	O
with	O
the	O
aim	O
of	O
searching	O
for	O
signs	O
of	O
extraterrestrial	O
intelligence	O
.	O
</s>
<s>
Until	O
March	O
2020	O
,	O
it	O
was	O
run	O
as	O
an	O
Internet-based	O
public	O
volunteer	B-Operating_System
computing	I-Operating_System
project	O
that	O
employed	O
the	O
BOINC	B-Operating_System
software	O
platform	O
.	O
</s>
<s>
SETI	B-Application
@home	I-Application
software	O
was	O
released	O
to	O
the	O
public	O
on	O
May	O
17	O
,	O
1999	O
,	O
making	O
it	O
the	O
third	O
large-scale	O
use	O
of	O
volunteer	B-Operating_System
computing	I-Operating_System
over	O
the	O
Internet	O
for	O
research	O
purposes	O
,	O
after	O
Great	O
Internet	O
Mersenne	O
Prime	O
Search	O
(	O
GIMPS	O
)	O
was	O
launched	O
in	O
1996	O
and	O
distributed.net	O
in	O
1997	O
.	O
</s>
<s>
Along	O
with	O
MilkyWay	B-Operating_System
@home	I-Operating_System
and	O
Einstein	B-Operating_System
@home	I-Operating_System
,	O
it	O
is	O
the	O
third	O
major	O
computing	O
project	O
of	O
this	O
type	O
that	O
has	O
the	O
investigation	O
of	O
phenomena	O
in	O
interstellar	O
space	O
as	O
its	O
primary	O
purpose	O
.	O
</s>
<s>
In	O
March	O
2020	O
,	O
the	O
project	O
stopped	O
sending	O
out	O
new	O
work	O
to	O
SETI	B-Application
@home	I-Application
users	O
,	O
bringing	O
the	O
crowdsourced	O
computing	O
aspect	O
of	O
the	O
project	O
to	O
a	O
stop	O
.	O
</s>
<s>
However	O
,	O
the	O
team	O
left	O
open	O
the	O
possibility	O
of	O
eventually	O
resuming	O
volunteer	B-Operating_System
computing	I-Operating_System
using	O
data	O
from	O
other	O
radio	O
telescopes	O
,	O
such	O
as	O
MeerKAT	B-Application
and	O
FAST	O
.	O
</s>
<s>
The	O
two	O
original	O
goals	O
of	O
SETI	B-Application
@home	I-Application
were	O
:	O
</s>
<s>
The	O
current	O
BOINC	B-Operating_System
environment	O
,	O
a	O
development	O
of	O
the	O
original	O
SETI	B-Application
@home	I-Application
,	O
is	O
providing	O
support	O
for	O
many	O
computationally	O
intensive	O
projects	O
in	O
a	O
wide	O
range	O
of	O
disciplines	O
.	O
</s>
<s>
The	O
first	O
of	O
these	O
goals	O
has	O
to	O
date	O
yielded	O
no	O
conclusive	O
results	O
:	O
no	O
evidence	O
for	O
ETI	O
signals	O
has	O
been	O
shown	O
via	O
SETI	B-Application
@home	I-Application
.	O
</s>
<s>
The	O
remainder	O
of	O
this	O
article	O
deals	O
specifically	O
with	O
the	O
original	O
SETI	B-Application
@home	I-Application
observations/analysis	O
.	O
</s>
<s>
SETI	B-Application
@home	I-Application
searches	O
for	O
possible	O
evidence	O
of	O
radio	O
transmissions	O
from	O
extraterrestrial	O
intelligence	O
using	O
observational	O
data	O
from	O
the	O
Arecibo	O
radio	O
telescope	O
and	O
the	O
Green	O
Bank	O
Telescope	O
.	O
</s>
<s>
The	O
data	O
is	O
digitized	O
,	O
stored	O
,	O
and	O
sent	O
to	O
the	O
SETI	B-Application
@home	I-Application
facility	O
.	O
</s>
<s>
Using	O
volunteer	B-Operating_System
computing	I-Operating_System
,	O
SETI	B-Application
@home	I-Application
sends	O
the	O
millions	O
of	O
chunks	O
of	O
data	O
to	O
be	O
analyzed	O
off-site	O
by	O
home	O
computers	O
,	O
and	O
then	O
have	O
those	O
computers	O
report	O
the	O
results	O
.	O
</s>
<s>
Checking	O
for	O
this	O
through	O
processing	O
is	O
done	O
,	O
to	O
an	O
extent	O
,	O
in	O
the	O
SETI	B-Application
@home	I-Application
software	O
.	O
</s>
<s>
More	O
technically	O
,	O
it	O
involves	O
a	O
lot	O
of	O
digital	O
signal	O
processing	O
,	O
mostly	O
discrete	B-Algorithm
Fourier	I-Algorithm
transforms	I-Algorithm
at	O
various	O
chirp	B-Application
rates	O
and	O
durations	O
.	O
</s>
<s>
While	O
the	O
project	O
has	O
not	O
reached	O
the	O
stated	O
primary	O
goal	O
of	O
finding	O
extraterrestrial	O
intelligence	O
,	O
it	O
has	O
proved	O
to	O
the	O
scientific	O
community	O
that	O
volunteer	B-Operating_System
computing	I-Operating_System
projects	O
using	O
Internet-connected	O
computers	O
can	O
succeed	O
as	O
a	O
viable	O
analysis	O
tool	O
,	O
and	O
even	O
beat	O
the	O
largest	O
supercomputers	B-Architecture
.	O
</s>
<s>
This	O
implies	O
that	O
a	O
prolonged	O
effort	O
may	O
benefit	O
SETI	B-Application
@home	I-Application
,	O
despite	O
its	O
(	O
present	O
)	O
twenty-year	O
run	O
without	O
success	O
in	O
ETI	O
detection	O
.	O
</s>
<s>
Anybody	O
with	O
an	O
at	O
least	O
intermittently	O
Internet-connected	O
computer	O
was	O
able	O
to	O
participate	O
in	O
SETI	B-Application
@home	I-Application
by	O
running	O
a	O
free	O
program	O
that	O
downloaded	O
and	O
analyzed	O
radio	O
telescope	O
data	O
.	O
</s>
<s>
Once	O
there	O
,	O
it	O
is	O
divided	O
in	O
both	O
time	O
and	O
frequency	O
domains	O
work	O
units	O
of	O
107	O
seconds	O
of	O
data	O
,	O
or	O
approximately	O
0.35	O
megabytes	O
(	O
350	O
kilobytes	O
or	O
350,000	O
bytes	B-Application
)	O
,	O
which	O
overlap	O
in	O
time	O
but	O
not	O
in	O
frequency	O
.	O
</s>
<s>
These	O
work	O
units	O
are	O
then	O
sent	O
from	O
the	O
SETI	B-Application
@home	I-Application
server	B-Application
over	O
the	O
Internet	O
to	O
personal	O
computers	O
around	O
the	O
world	O
to	O
analyze	O
.	O
</s>
<s>
Data	O
was	O
merged	O
into	O
a	O
database	O
using	O
SETI	B-Application
@home	I-Application
computers	O
in	O
Berkeley	O
.	O
</s>
<s>
The	O
project	O
used	O
CUDA	B-Architecture
for	O
GPU	B-Architecture
processing	O
starting	O
in	O
2015	O
.	O
</s>
<s>
In	O
2016	O
SETI	B-Application
@home	I-Application
began	O
processing	O
data	O
from	O
the	O
Breakthrough	O
Listen	O
project	O
.	O
</s>
<s>
The	O
SETI	B-Application
@home	I-Application
volunteer	B-Operating_System
computing	I-Operating_System
software	O
ran	O
either	O
as	O
a	O
screensaver	B-General_Concept
or	O
continuously	O
while	O
a	O
user	O
worked	O
,	O
making	O
use	O
of	O
processor	O
time	O
that	O
would	O
otherwise	O
be	O
unused	O
.	O
</s>
<s>
The	O
initial	O
software	O
platform	O
,	O
now	O
referred	O
to	O
as	O
"	O
SETI	B-Application
@home	I-Application
Classic	O
,	O
"	O
ran	O
from	O
May	O
17	O
,	O
1999	O
,	O
to	O
December	O
15	O
,	O
2005	O
.	O
</s>
<s>
This	O
program	O
was	O
only	O
capable	O
of	O
running	O
SETI	B-Application
@home	I-Application
;	O
it	O
was	O
replaced	O
by	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
,	O
which	O
also	O
allows	O
users	O
to	O
contribute	O
to	O
other	O
volunteer	B-Operating_System
computing	I-Operating_System
projects	O
at	O
the	O
same	O
time	O
as	O
running	O
SETI	B-Application
@home	I-Application
.	O
</s>
<s>
The	O
BOINC	B-Operating_System
platform	O
also	O
allowed	O
testing	O
for	O
more	O
types	O
of	O
signals	O
.	O
</s>
<s>
The	O
discontinuation	O
of	O
the	O
SETI	B-Application
@home	I-Application
Classic	O
platform	O
rendered	O
older	O
Macintosh	B-Device
computers	I-Device
running	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
(	O
pre	O
December	O
,	O
2001	O
)	O
unsuitable	O
for	O
participating	O
in	O
the	O
project	O
.	O
</s>
<s>
SETI	B-Application
@home	I-Application
was	O
available	O
for	O
the	O
Sony	B-Operating_System
PlayStation	I-Operating_System
3	I-Operating_System
console	O
.	O
</s>
<s>
On	O
May	O
3	O
,	O
2006	O
,	O
new	O
work	O
units	O
for	O
a	O
new	O
version	O
of	O
SETI	B-Application
@home	I-Application
called	O
"	O
SETI	B-Application
@home	I-Application
Enhanced	O
"	O
started	O
distribution	O
.	O
</s>
<s>
Since	O
computers	O
had	O
the	O
power	O
for	O
more	O
computationally	O
intensive	O
work	O
than	O
when	O
the	O
project	O
began	O
,	O
this	O
new	O
version	O
was	O
more	O
sensitive	O
by	O
a	O
factor	O
of	O
two	O
concerning	O
Gaussian	O
signals	O
and	O
to	O
some	O
kinds	O
of	O
pulsed	O
signals	O
than	O
the	O
original	O
SETI	B-Application
@home	I-Application
(	O
BOINC	B-Operating_System
)	O
software	O
.	O
</s>
<s>
In	O
addition	O
,	O
some	O
distributions	O
of	O
the	O
SETI	B-Application
@home	I-Application
applications	O
were	O
optimized	O
for	O
a	O
particular	O
type	O
of	O
CPU	B-General_Concept
.	O
</s>
<s>
They	O
were	O
referred	O
to	O
as	O
"	O
optimized	O
executables	O
"	O
,	O
and	O
had	O
been	O
found	O
to	O
run	O
faster	O
on	O
systems	O
specific	O
for	O
that	O
CPU	B-General_Concept
.	O
</s>
<s>
,	O
most	O
of	O
these	O
applications	O
were	O
optimized	O
for	O
Intel	O
processors	O
and	O
their	O
corresponding	O
instruction	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
With	O
over	O
5.2million	O
participants	O
worldwide	O
,	O
the	O
project	O
was	O
the	O
volunteer	B-Operating_System
computing	I-Operating_System
project	O
with	O
the	O
most	O
participants	O
to	O
date	O
.	O
</s>
<s>
The	O
original	O
intent	O
of	O
SETI	B-Application
@home	I-Application
was	O
to	O
utilize	O
50,000	O
–	O
100,000	O
home	O
computers	O
.	O
</s>
<s>
On	O
September	O
26	O
,	O
2001	O
,	O
SETI	B-Application
@home	I-Application
had	O
performed	O
a	O
total	O
of	O
1021	O
floating	B-Algorithm
point	I-Algorithm
operations	O
.	O
</s>
<s>
With	O
over	O
145,000	O
active	O
computers	O
in	O
the	O
system	O
(	O
1.4million	O
total	O
)	O
in	O
233	O
countries	O
,	O
,	O
SETI	B-Application
@home	I-Application
had	O
the	O
ability	O
to	O
compute	O
over	O
668	O
teraFLOPS	O
.	O
</s>
<s>
For	O
comparison	O
,	O
the	O
Tianhe-2	B-Device
computer	O
,	O
which	O
was	O
the	O
world	O
's	O
fastest	B-Operating_System
supercomputer	I-Operating_System
,	O
was	O
able	O
to	O
compute	O
33.86	O
petaFLOPS	O
(	O
approximately	O
50	O
times	O
greater	O
)	O
.	O
</s>
<s>
Other	O
plans	O
include	O
a	O
Multi-Beam	O
Data	O
Recorder	O
,	O
a	O
Near	O
Time	O
Persistency	O
Checker	O
and	O
Astropulse	B-Operating_System
(	O
an	O
application	O
that	O
uses	O
coherent	O
dedispersion	O
to	O
search	O
for	O
pulsed	O
signals	O
)	O
.	O
</s>
<s>
Astropulse	B-Operating_System
will	O
team	O
with	O
the	O
original	O
SETI	B-Application
@home	I-Application
to	O
detect	O
other	O
sources	O
,	O
such	O
as	O
rapidly	O
rotating	O
pulsars	O
,	O
exploding	O
primordial	O
black	O
holes	O
,	O
or	O
as-yet	O
unknown	O
astrophysical	O
phenomena	O
.	O
</s>
<s>
Beta	O
testing	O
of	O
the	O
final	O
public	O
release	O
version	O
of	O
Astropulse	B-Operating_System
was	O
completed	O
in	O
July	O
2008	O
,	O
and	O
the	O
distribution	O
of	O
work	O
units	O
to	O
higher	O
spec	O
machines	O
capable	O
of	O
processing	O
the	O
more	O
CPU	B-General_Concept
intensive	O
work	O
units	O
started	O
in	O
mid-July	O
2008	O
.	O
</s>
<s>
On	O
March	O
31	O
,	O
2020	O
,	O
UC	O
Berkeley	O
stopped	O
sending	O
out	O
new	O
data	O
for	O
SETI	B-Application
@Home	I-Application
clients	O
to	O
process	O
,	O
ending	O
the	O
effort	O
for	O
the	O
time	O
being	O
.	O
</s>
<s>
SETI	B-Application
@home	I-Application
users	O
quickly	O
started	O
to	O
compete	O
with	O
one	O
another	O
to	O
process	O
the	O
maximum	O
number	O
of	O
work	O
units	O
.	O
</s>
<s>
The	O
competition	O
continued	O
and	O
grew	O
larger	O
with	O
the	O
introduction	O
of	O
BOINC	B-Operating_System
.	O
</s>
<s>
To	O
combat	O
cheats	O
,	O
the	O
SETI	B-Application
@home	I-Application
system	O
sends	O
every	O
work	O
unit	O
to	O
multiple	O
computers	O
,	O
a	O
value	O
known	O
as	O
"	O
initial	O
replication	O
"	O
(	O
currently	O
2	O
)	O
.	O
</s>
<s>
Some	O
users	O
have	O
installed	O
and	O
run	O
SETI	B-Application
@home	I-Application
on	O
computers	O
at	O
their	O
workplaces	O
;	O
an	O
act	O
known	O
as	O
"	O
Borging	O
"	O
,	O
after	O
the	O
assimilation-driven	O
Borg	O
of	O
Star	B-Operating_System
Trek	I-Operating_System
.	O
</s>
<s>
In	O
some	O
cases	O
,	O
SETI	B-Application
@home	I-Application
users	O
have	O
misused	O
company	O
resources	O
to	O
gain	O
work-unit	O
results	O
with	O
at	O
least	O
two	O
individuals	O
getting	O
fired	O
for	O
running	O
SETI	B-Application
@home	I-Application
on	O
an	O
enterprise	O
production	O
system	O
.	O
</s>
<s>
There	O
is	O
a	O
thread	O
in	O
the	O
newsgroup	O
alt.sci.seti	O
which	O
bears	O
the	O
title	O
"	O
Anyone	O
fired	O
for	O
SETI	O
screensaver	B-General_Concept
"	O
and	O
ran	O
starting	O
as	O
early	O
as	O
September	O
14	O
,	O
1999	O
.	O
</s>
<s>
Other	O
users	O
collect	O
large	O
quantities	O
of	O
equipment	O
together	O
at	O
home	O
to	O
create	O
"	O
SETI	B-Application
farms	I-Application
"	O
,	O
which	O
typically	O
consist	O
of	O
a	O
number	O
of	O
computers	O
consisting	O
of	O
only	O
a	O
motherboard	B-Device
,	O
CPU	B-General_Concept
,	O
RAM	B-Architecture
and	O
power	O
supply	O
that	O
are	O
arranged	O
on	O
shelves	O
as	O
diskless	O
workstations	B-Device
running	O
either	O
Linux	B-Application
or	O
old	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
"	O
headless	O
"	O
(	O
without	O
a	O
monitor	O
)	O
.	O
</s>
<s>
Until	O
2020	O
,	O
SETI	B-Application
@home	I-Application
procured	O
its	O
data	O
from	O
the	O
Arecibo	O
Observatory	O
facility	O
that	O
was	O
operated	O
by	O
the	O
National	O
Astronomy	O
and	O
Ionosphere	O
Center	O
and	O
administered	O
by	O
SRI	O
International	O
.	O
</s>
<s>
The	O
decreasing	O
operating	O
budget	O
for	O
the	O
observatory	O
has	O
created	O
a	O
shortfall	O
of	O
funds	O
which	O
has	O
not	O
been	O
made	O
up	O
from	O
other	O
sources	O
such	O
as	O
private	O
donors	O
,	O
NASA	O
,	O
other	O
foreign	O
research	O
institutions	O
,	O
nor	O
private	O
non-profit	O
organizations	O
such	O
as	O
SETI	B-Application
@home	I-Application
.	O
</s>
<s>
In	O
one	O
documented	O
case	O
,	O
an	O
individual	O
was	O
fired	O
for	O
explicitly	O
importing	O
and	O
using	O
the	O
SETI	B-Application
@home	I-Application
software	O
on	O
computers	O
used	O
for	O
the	O
U.S.	O
state	O
of	O
Ohio	O
.	O
</s>
<s>
In	O
another	O
incident	O
a	O
school	O
IT	O
director	O
resigned	O
after	O
his	O
installation	O
allegedly	O
cost	O
his	O
school	O
district	O
$1million	O
in	O
removal	O
costs	O
;	O
however	O
,	O
other	O
reasons	O
for	O
this	O
firing	O
included	O
lack	O
of	O
communication	O
with	O
his	O
superiors	O
,	O
not	O
installing	O
firewall	B-Application
software	I-Application
and	O
alleged	O
theft	O
of	O
computer	O
equipment	O
,	O
leading	O
a	O
ZDNet	O
editor	O
to	O
comment	O
that	O
"	O
the	O
volunteer	B-Operating_System
computing	I-Operating_System
nonsense	O
was	O
simply	O
the	O
best	O
and	O
most	O
obvious	O
excuse	O
the	O
district	O
had	O
to	O
terminate	O
his	O
contract	O
with	O
cause	O
"	O
.	O
</s>
<s>
,	O
approximately	O
one-third	O
of	O
the	O
processing	O
for	O
the	O
non-BOINC	O
version	O
of	O
the	O
software	O
was	O
performed	O
on	O
work	O
or	O
school	O
based	O
machines	O
.	O
</s>
<s>
To	O
some	O
extent	O
,	O
this	O
may	O
be	O
offset	O
by	O
better	O
connectivity	O
to	O
home	O
machines	O
and	O
increasing	O
performance	O
of	O
home	O
computers	O
,	O
especially	O
those	O
with	O
GPUs	B-Architecture
,	O
which	O
have	O
also	O
benefited	O
other	O
volunteer	B-Operating_System
computing	I-Operating_System
projects	O
such	O
as	O
Folding	B-Application
@Home	I-Application
.	O
</s>
<s>
The	O
spread	O
of	O
mobile	O
computing	O
devices	O
provides	O
another	O
large	O
resource	O
for	O
volunteer	B-Operating_System
computing	I-Operating_System
.	O
</s>
<s>
For	O
example	O
,	O
in	O
2012	O
,	O
Piotr	O
Luszczek	O
(	O
a	O
former	O
doctoral	O
student	O
of	O
Jack	O
Dongarra	O
)	O
,	O
presented	O
results	O
showing	O
that	O
an	O
iPad	B-Operating_System
2	I-Operating_System
matched	O
the	O
historical	O
performance	O
of	O
a	O
Cray-2	B-Device
(	O
the	O
fastest	B-Operating_System
computer	I-Operating_System
in	O
the	O
world	O
in	O
1985	O
)	O
on	O
an	O
embedded	O
LINPACK	B-Application
benchmark	O
.	O
</s>
<s>
In	O
a	O
December	O
16	O
,	O
2007	O
plea	O
for	O
donations	O
,	O
SETI	B-Application
@home	I-Application
stated	O
its	O
present	O
modest	O
state	O
and	O
urged	O
donations	O
of	O
$	O
476,000	O
needed	O
for	O
continuation	O
into	O
2008	O
.	O
</s>
<s>
BOINC	B-Operating_System
will	O
run	O
on	O
unofficial	O
clients	O
;	O
however	O
,	O
clients	O
that	O
return	O
different	O
and	O
therefore	O
incorrect	O
data	O
are	O
not	O
allowed	O
,	O
so	O
corrupting	O
the	O
result	O
database	O
is	O
avoided	O
.	O
</s>
<s>
BOINC	B-Operating_System
relies	O
on	O
cross-checking	O
to	O
validate	O
data	O
but	O
unreliable	O
clients	O
need	O
to	O
be	O
identified	O
,	O
to	O
avoid	O
situations	O
when	O
two	O
of	O
these	O
report	O
the	O
same	O
invalid	O
data	O
and	O
therefore	O
corrupt	O
the	O
database	O
.	O
</s>
<s>
A	O
very	O
popular	O
unofficial	O
client	O
(	O
lunatic	O
)	O
allows	O
users	O
to	O
take	O
advantage	O
of	O
the	O
special	O
features	O
provided	O
by	O
their	O
processor(s )	O
such	O
as	O
SSE	B-General_Concept
,	O
SSE2	B-General_Concept
,	O
SSE3	B-General_Concept
,	O
SSSE3	B-General_Concept
,	O
SSE4.1	O
,	O
and	O
AVX	B-General_Concept
to	O
allow	O
for	O
faster	O
processing	O
.	O
</s>
<s>
SETI	B-Application
@home	I-Application
is	O
a	O
test	O
bed	O
for	O
further	O
development	O
not	O
only	O
of	O
BOINC	B-Operating_System
but	O
of	O
other	O
hardware	O
and	O
software	O
(	O
database	O
)	O
technology	O
.	O
</s>
<s>
Under	O
SETI	B-Application
@home	I-Application
processing	O
loads	O
,	O
these	O
experimental	O
technologies	O
can	O
be	O
more	O
challenging	O
than	O
expected	O
,	O
as	O
SETI	O
databases	O
do	O
not	O
have	O
typical	O
accounting	O
and	O
business	O
data	O
or	O
relational	O
structures	O
.	O
</s>
