<s>
OPUS	B-Language
is	O
an	O
open-source	B-Application
software	I-Application
package	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
used	O
for	O
creating	O
Open	O
Access	O
repositories	O
that	O
are	O
compliant	O
with	O
the	O
Open	O
Archives	O
Initiative	O
Protocol	O
for	O
Metadata	O
Harvesting	O
.	O
</s>
<s>
OPUS	B-Language
,	O
originally	O
an	O
acronym	O
for	O
the	O
Online	O
Publikationsverbund	O
der	O
Universität	O
Stuttgart	O
,	O
was	O
developed	O
with	O
the	O
support	O
of	O
the	O
Deutsches	O
Forschungsnetz	O
(	O
DFN	O
)	O
in	O
1997	O
and	O
1998	O
at	O
the	O
University	O
of	O
Stuttgart	O
Library	O
.	O
</s>
<s>
OPUS	B-Language
is	O
used	O
at	O
many	O
universities	O
and	O
library	O
networks	O
.	O
</s>
<s>
In	O
Germany	O
,	O
the	O
OPUS	B-Language
software	O
is	O
the	O
most	O
commonly	O
used	O
for	O
the	O
operation	O
of	O
open	O
access	O
repositories	O
(	O
according	O
to	O
a	O
survey	O
carried	O
out	O
in	O
2012	O
,	O
77	O
repositories	O
were	O
based	O
on	O
OPUS	B-Language
)	O
.	O
</s>
<s>
OPUS-based	O
repositories	O
may	O
either	O
be	O
hosted	O
and	O
operated	O
by	O
universities	O
on	O
their	O
own	O
,	O
or	O
as	O
part	O
of	O
hosting	O
services	O
provided	O
by	O
the	O
German	O
library	O
network	O
.	O
</s>
<s>
The	O
KOBV	O
provides	O
hosting	O
for	O
more	O
than	O
35	O
instances	O
of	O
OPUS	B-Language
.	O
</s>
<s>
Apart	O
from	O
Germany	O
,	O
OPUS	B-Language
is	O
also	O
used	O
in	O
Serbia	O
by	O
two	O
research	O
institutes	O
.	O
</s>
<s>
The	O
current	O
version	O
,	O
OPUS	B-Language
4	O
,	O
is	O
being	O
developed	O
by	O
the	O
Cooperative	O
Library	O
Network	O
Berlin-Brandenburg	O
(	O
KOBV	O
)	O
at	O
the	O
Zuse	O
Institute	O
Berlin	O
(	O
ZIB	O
)	O
.	O
</s>
<s>
OPUS	B-Language
3.x	O
was	O
written	O
in	O
PHP	B-Application
4	O
.	O
</s>
<s>
The	O
current	O
version	O
,	O
OPUS	B-Language
4	O
,	O
is	O
developed	O
in	O
PHP	B-Application
(	O
version	O
5.3	O
)	O
and	O
is	O
based	O
on	O
the	O
Zend	B-Language
Framework	I-Language
and	O
the	O
search	O
engine	O
Solr	B-Language
.	O
</s>
<s>
Data	O
are	O
stored	O
in	O
a	O
MySQL	B-Application
database	O
.	O
</s>
<s>
Both	O
versions	O
are	O
designed	O
for	O
LAMP	B-Application
environments	O
.	O
</s>
<s>
OPUS	B-Language
is	O
a	O
simple	O
repository	O
system	O
for	O
various	O
types	O
of	O
objects	O
and	O
formats	O
.	O
</s>
<s>
Metadata	O
can	O
be	O
harvested	O
by	O
different	O
search	O
engines	O
(	O
e.g	O
OAI	O
service	O
providers	O
,	O
Google	B-Library
Scholar	I-Library
,	O
WorldCat	B-Library
)	O
.	O
</s>
<s>
OPUS	B-Language
supports	O
Uniform	O
Resource	O
Names	O
(	O
URN	O
)	O
for	O
persistent	O
identification	O
of	O
objects	O
.	O
</s>
<s>
OPUS	B-Language
has	O
a	O
license	O
module	O
;	O
various	O
types	O
of	O
licenses	O
(	O
Digital	O
Peer	O
Publishing	O
,	O
Creative	O
Commons	O
,	O
etc	O
.	O
)	O
</s>
<s>
OPUS	B-Language
supports	O
OAI-PMH	O
2.0	O
protocol	O
.	O
</s>
<s>
OPUS	B-Language
supports	O
XmetaDiss	O
,	O
the	O
metadata	O
set	O
of	O
the	O
German	O
National	O
Library	O
for	O
online	O
dissertations	O
and	O
post-doctoral	O
theses	O
.	O
</s>
