<s>
Storage	B-Operating_System
Resource	I-Operating_System
Broker	I-Operating_System
(	O
SRB	O
)	O
is	O
data	B-General_Concept
grid	I-General_Concept
management	O
computer	B-Application
software	I-Application
used	O
in	O
computational	O
science	O
research	O
projects	O
.	O
</s>
<s>
SRB	O
is	O
a	O
logical	O
distributed	O
file	B-Application
system	I-Application
based	O
on	O
a	O
client-server	B-Operating_System
architecture	I-Operating_System
which	O
presents	O
users	O
with	O
a	O
single	O
global	O
logical	O
namespace	O
or	O
file	O
hierarchy	O
.	O
</s>
<s>
Essentially	O
,	O
the	B-Application
software	I-Application
enables	O
a	O
user	O
to	O
use	O
a	O
single	O
mechanism	O
to	O
work	O
with	O
multiple	O
data	O
sources	O
.	O
</s>
<s>
SRB	O
provides	O
a	O
uniform	O
interface	O
to	O
heterogeneous	O
computer	B-General_Concept
data	I-General_Concept
storage	I-General_Concept
resources	O
over	O
a	O
network	O
.	O
</s>
<s>
As	O
part	O
of	O
this	O
,	O
it	O
implements	O
a	O
logical	O
namespace	O
(	O
distinct	O
from	O
physical	O
file	O
names	O
)	O
and	O
maintains	O
metadata	O
on	O
data-objects	O
(	O
files	O
)	O
,	O
users	O
,	O
groups	O
,	O
resources	O
,	O
collections	O
,	O
and	O
other	O
items	O
in	O
an	O
SRB	O
metadata	O
catalog	O
(	O
MCAT	O
)	O
stored	O
in	O
a	O
relational	O
database	B-Application
management	I-Application
system	I-Application
.	O
</s>
<s>
SRB	O
runs	O
on	O
various	O
versions	O
of	O
Unix	B-Application
,	O
Linux	B-Application
,	O
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
The	O
SRB	O
system	O
is	O
middleware	B-General_Concept
in	O
the	O
sense	O
that	O
it	O
is	O
built	O
on	O
top	O
of	O
other	O
major	O
software	O
packages	O
(	O
various	O
storage	B-General_Concept
systems	I-General_Concept
,	O
real-time	O
data	O
sources	O
,	O
a	O
relational	O
database	B-Application
management	I-Application
system	I-Application
,	O
etc	O
.	O
)	O
</s>
<s>
and	O
it	O
has	O
callable	O
library	O
functions	O
that	O
can	O
be	O
utilized	O
by	O
higher	O
level	O
software	B-Application
.	I-Application
</s>
<s>
However	O
,	O
it	O
is	O
more	O
complete	O
than	O
many	O
middleware	B-General_Concept
software	O
systems	O
as	O
it	O
implements	O
a	O
comprehensive	O
distributed	O
data	O
management	O
environment	O
,	O
including	O
various	O
end-user	O
client	O
applications	O
.	O
</s>
<s>
SRB	O
is	O
sometimes	O
used	O
in	O
conjunction	O
with	O
computational	B-Architecture
grid	I-Architecture
computing	O
systems	O
,	O
such	O
as	O
Globus	O
Alliance	O
,	O
and	O
can	O
utilize	O
the	O
Globus	O
Alliance	O
Grid	O
Security	O
Infrastructure	O
(	O
GSI	O
)	O
authentication	O
system	O
.	O
</s>
<s>
SRB	O
can	O
store	O
and	O
retrieve	O
data	O
in	O
archival	O
storage	B-General_Concept
systems	I-General_Concept
such	O
as	O
the	O
High	B-Application
Performance	I-Application
Storage	I-Application
System	I-Application
and	O
SAM-FS	O
,	O
on	O
disk	B-Application
file	I-Application
systems	I-Application
(	O
Unix	B-Application
,	O
Linux	B-Application
,	O
or	O
Windows	O
)	O
,	O
as	O
binary	B-General_Concept
large	I-General_Concept
objects	I-General_Concept
or	O
tabular	O
data	O
in	O
relational	O
database	B-Application
management	I-Application
systems	I-Application
,	O
and	O
on	O
tape	O
libraries	O
.	O
</s>
<s>
Nirvana	B-General_Concept
SRB	O
,	O
a	O
commercial	O
version	O
of	O
SRB	O
,	O
featured	O
capabilities	O
specifically	O
adapted	O
to	O
government	O
and	O
commercial	O
use	O
.	O
</s>
