<s>
UNICORE	B-Operating_System
(	O
UNiform	O
Interface	O
to	O
COmputing	O
REsources	O
)	O
is	O
a	O
grid	B-Architecture
computing	I-Architecture
technology	O
for	O
resources	O
such	O
as	O
supercomputers	B-Architecture
or	O
cluster	B-Architecture
systems	I-Architecture
and	O
information	O
stored	O
in	O
databases	O
.	O
</s>
<s>
UNICORE	B-Operating_System
was	O
developed	O
in	O
two	O
projects	O
funded	O
by	O
the	O
German	O
ministry	O
for	O
education	O
and	O
research	O
(	O
BMBF	O
)	O
.	O
</s>
<s>
In	O
European-funded	O
projects	O
UNICORE	B-Operating_System
evolved	O
to	O
a	O
middleware	O
system	O
used	O
at	O
several	O
supercomputer	B-Architecture
centers	O
.	O
</s>
<s>
UNICORE	B-Operating_System
served	O
as	O
a	O
basis	O
in	O
other	O
research	O
projects	O
.	O
</s>
<s>
The	O
UNICORE	B-Operating_System
technology	O
is	O
open	O
source	O
under	O
BSD	B-Operating_System
licence	O
and	O
available	O
at	O
SourceForge	B-Application
.	O
</s>
<s>
The	O
concept	O
of	O
grid	B-Architecture
computing	I-Architecture
was	O
first	O
introduced	O
in	O
the	O
book	O
"	O
The	O
Grid	O
:	O
Blueprint	O
for	O
a	O
New	O
Computing	O
Infrastructure	O
"	O
at	O
the	O
end	O
of	O
1998	O
.	O
</s>
<s>
By	O
1997	O
,	O
the	O
development	O
of	O
UNICORE	B-Operating_System
was	O
initiated	O
for	O
German	O
supercomputer	B-Architecture
centers	O
as	O
an	O
alternative	O
for	O
the	O
Globus	O
Toolkit	O
.	O
</s>
<s>
The	O
first	O
prototype	O
was	O
developed	O
in	O
the	O
German	O
UNICORE	B-Operating_System
project	O
,	O
while	O
the	O
foundations	O
for	O
the	O
production	O
version	O
were	O
laid	O
in	O
the	O
follow-up	O
project	O
UNICORE	B-Operating_System
Plus	O
,	O
which	O
ended	O
in	O
2002	O
.	O
</s>
<s>
These	O
resulted	O
in	O
the	O
release	O
of	O
UNICORE	B-Operating_System
6	O
on	O
28	O
August	O
2007	O
.	O
</s>
<s>
UNICORE	B-Operating_System
consists	O
of	O
three	O
layers	O
:	O
a	O
user	O
,	O
server	O
,	O
and	O
target	O
system	O
tier	O
.	O
</s>
<s>
The	O
primary	O
clients	O
are	O
the	O
UNICORE	B-Operating_System
Rich	O
Client	O
,	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
based	O
on	O
the	O
Eclipse	O
framework	O
,	O
and	O
the	O
UNICORE	B-Operating_System
commandline	O
client	O
(	O
UCC	O
)	O
.	O
</s>
<s>
The	O
servers	O
are	O
accessible	O
only	O
via	O
the	O
Secure	B-Protocol
Sockets	I-Protocol
Layer	I-Protocol
protocol	O
.	O
</s>
<s>
As	O
the	O
single	O
secure	O
entry	O
point	O
to	O
a	O
UNICORE	B-Operating_System
site	O
,	O
the	O
Gateway	O
accepts	O
and	O
authenticates	O
all	O
requests	O
,	O
and	O
forwards	O
them	O
to	O
the	O
target	O
service	O
.	O
</s>
<s>
A	O
further	O
server	O
,	O
UNICORE/X	O
,	O
is	O
used	O
to	O
access	O
a	O
particular	O
set	O
of	O
Grid	O
resources	O
at	O
a	O
site	O
.	O
</s>
<s>
UNICORE	B-Operating_System
supports	O
many	O
different	O
system	O
architectures	O
and	O
ensures	O
that	O
organization	O
full	O
control	O
over	O
its	O
resources	O
.	O
</s>
<s>
UNICORE/X	O
servers	O
may	O
be	O
used	O
to	O
access	O
a	O
supercomputer	B-Architecture
,	O
a	O
Linux	B-Architecture
cluster	I-Architecture
or	O
a	O
single	O
PC	O
.	O
</s>
<s>
The	O
UNICORE/X	O
server	O
creates	O
concrete	O
target	O
system	O
specific	O
actions	O
from	O
the	O
XML	O
job	O
description	O
(	O
Abstract	B-Operating_System
Job	I-Operating_System
Objects	I-Operating_System
,	O
AJO	O
)	O
received	O
from	O
the	O
client	O
.	O
</s>
<s>
Available	O
UNICORE	B-Operating_System
services	O
include	O
job	O
submission	O
and	O
job	O
management	O
,	O
file	O
access	O
,	O
file	O
transfer	O
(	O
both	O
client-server	O
and	O
server-server	O
)	O
,	O
</s>
<s>
The	O
security	O
within	O
UNICORE	B-Operating_System
relies	O
on	O
the	O
usage	O
of	O
permanent	O
X.509	O
certificates	O
issued	O
by	O
a	O
trusted	O
Certificate	B-Architecture
Authority	I-Architecture
(	O
CA	O
)	O
.	O
</s>
<s>
These	O
certificates	O
are	O
used	O
to	O
provide	O
a	O
single	O
sign-on	O
in	O
the	O
UNICORE	B-Operating_System
client	O
,	O
i.e.	O
</s>
<s>
In	O
addition	O
the	O
certificates	O
are	O
used	O
for	O
authentication	O
and	O
authorization	O
,	O
including	O
the	O
mapping	O
of	O
UNICORE	B-Operating_System
user	O
certificates	O
to	O
local	O
accounts	O
,	O
e.g.	O
</s>
<s>
Unix	B-Application
uid/gid	O
,	O
and	O
for	O
signing	O
XML	O
requests	O
,	O
which	O
are	O
sent	O
over	O
SSL	O
based	O
communication	O
channels	O
across	O
'	O
insecure	O
 '	O
internet	O
links	O
.	O
</s>
<s>
released	O
by	O
the	O
Global	O
Grid	O
Forum	O
(	O
GGF	O
)	O
,	O
within	O
the	O
UNICORE	B-Operating_System
architecture	O
.	O
</s>
<s>
For	O
trust	O
delegation	O
,	O
UNICORE	B-Operating_System
uses	O
signed	O
SAML	O
assertions	O
,	O
while	O
local	O
authorisation	O
is	O
controlled	O
by	O
XACML	O
policies	O
.	O
</s>
<s>
All	O
components	O
of	O
the	O
UNICORE	B-Operating_System
technology	O
are	O
open	O
source	O
software	O
under	O
BSD	B-Operating_System
license	O
and	O
can	O
be	O
downloaded	O
from	O
the	O
SourceForge	B-Application
repository	O
.	O
</s>
<s>
Many	O
European	O
and	O
international	O
research	O
projects	O
base	O
their	O
Grid	O
software	O
implementations	O
on	O
UNICORE	B-Operating_System
,	O
e.g.	O
</s>
<s>
These	O
projects	O
extended	O
or	O
are	O
extending	O
the	O
set	O
of	O
core	O
UNICORE	B-Operating_System
functions	O
,	O
including	O
new	O
features	O
specific	O
to	O
their	O
research	O
or	O
project	O
focus	O
.	O
</s>
<s>
Other	O
scientific	O
domains	O
such	O
as	O
bioengineering	O
or	O
computational	O
chemistry	O
are	O
also	O
using	O
UNICORE	B-Operating_System
as	O
the	O
basis	O
for	O
their	O
work	O
and	O
research	O
,	O
like	O
in	O
the	O
OpenMolGRID	O
or	O
Chemomentum	O
projects	O
.	O
</s>
<s>
Within	O
the	O
European	O
DEISA	O
project	O
leading	O
HPC	O
centers	O
in	O
Europe	O
joined	O
to	O
deploy	O
and	O
operate	O
a	O
pervasive	O
,	O
distributed	O
,	O
heterogeneous	O
,	O
multi-tera-scale	O
supercomputing	B-Architecture
platform	O
.	O
</s>
<s>
UNICORE	B-Operating_System
was	O
used	O
as	O
the	O
Grid	O
middleware	O
to	O
access	O
the	O
DEISA	O
resources	O
.	O
</s>
<s>
UNICORE	B-Operating_System
is	O
deployed	O
in	O
distributed	O
computing	O
infrastructures	O
in	O
Europe	O
(	O
PRACE	O
,	O
the	O
European	O
Grid	O
Infrastructure	O
EGI	O
)	O
and	O
is	O
foreseen	O
to	O
be	O
deployed	O
in	O
the	O
upcoming	O
Extreme	O
Science	O
and	O
Engineering	O
Discovery	O
Environment	O
(	O
XSEDE	O
)	O
infrastructure	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
UNICORE	B-Operating_System
is	O
successfully	O
used	O
in	O
production	O
environments	O
,	O
e.g.	O
</s>
<s>
within	O
the	O
John	O
von	O
Neumann-Institute	O
for	O
Computing	O
(	O
NIC	O
)	O
to	O
access	O
the	O
294912	O
core	O
"	O
JUGENE	O
"	O
IBM	O
BlueGene/P	O
supercomputer	B-Architecture
and	O
the	O
26304	O
core	O
"	O
JUROPA	O
"	O
cluster	O
.	O
</s>
