<s>
Berkeley	B-Language
DB	I-Language
(	O
BDB	O
)	O
is	O
an	O
unmaintained	O
embedded	B-Application
database	I-Application
software	B-Library
library	I-Library
for	O
key/value	B-Data_Structure
data	O
,	O
historically	O
significant	O
in	O
open	B-Application
source	I-Application
software	I-Application
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
is	O
written	O
in	O
C	B-Language
with	O
API	B-Application
bindings	O
for	O
many	O
other	O
programming	O
languages	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
is	O
not	O
a	O
relational	B-Application
database	I-Application
,	O
although	O
it	O
has	O
database	O
features	O
including	O
database	B-General_Concept
transactions	I-General_Concept
,	O
multiversion	B-Operating_System
concurrency	I-Operating_System
control	I-Operating_System
and	O
write-ahead	B-Algorithm
logging	I-Algorithm
.	O
</s>
<s>
BDB	O
runs	O
on	O
a	O
wide	O
variety	O
of	O
operating	B-General_Concept
systems	I-General_Concept
including	O
most	O
Unix-like	B-Operating_System
and	O
Windows	B-Application
systems	O
,	O
and	O
real-time	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Sleepycat	O
Software	O
was	O
acquired	O
by	O
Oracle	B-Application
Corporation	I-Application
in	O
February	O
2006	O
,	O
who	O
continued	O
to	O
develop	O
and	O
sell	O
the	O
C	B-Language
Berkeley	B-Language
DB	I-Language
library	B-Library
.	O
</s>
<s>
In	O
2013	O
Oracle	B-Application
re-licensed	O
BDB	O
under	O
the	O
AGPL	B-Application
license	O
.	O
</s>
<s>
Bloomberg	O
LP	O
continues	O
to	O
develop	O
a	O
fork	B-Application
of	O
the	O
2013	O
version	O
of	O
BDB	O
within	O
their	O
Comdb2	B-Application
database	O
,	O
under	O
the	O
original	O
Sleepycat	B-License
permissive	I-License
license	I-License
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
originated	O
at	O
the	O
University	O
of	O
California	O
,	O
Berkeley	O
as	O
part	O
of	O
BSD	B-Operating_System
,	O
Berkeley	O
's	O
version	O
of	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
After	O
4.3BSD	O
(	O
1986	O
)	O
,	O
the	O
BSD	B-Operating_System
developers	O
attempted	O
to	O
remove	O
or	O
replace	O
all	O
code	O
originating	O
in	O
the	O
original	O
AT&T	B-Operating_System
Unix	I-Operating_System
from	O
which	O
BSD	B-Operating_System
was	O
derived	O
.	O
</s>
<s>
In	O
doing	O
so	O
,	O
they	O
needed	O
to	O
rewrite	O
the	O
Unix	B-Application
database	O
package	O
.	O
</s>
<s>
Seltzer	O
and	O
Yigit	O
created	O
a	O
new	O
database	O
,	O
unencumbered	O
by	O
any	O
AT&T	O
patents	O
:	O
an	O
on-disk	O
hash	B-Algorithm
table	I-Algorithm
that	O
outperformed	O
the	O
existing	O
dbm	B-General_Concept
libraries	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
itself	O
was	O
first	O
released	O
in	O
1991	O
and	O
later	O
included	O
with	O
4.4BSD	O
.	O
</s>
<s>
In	O
1996	O
Netscape	B-Protocol
requested	O
that	O
the	O
authors	O
of	O
Berkeley	B-Language
DB	I-Language
improve	O
and	O
extend	O
the	O
library	B-Library
,	O
then	O
at	O
version	O
1.86	O
,	O
to	O
suit	O
Netscape	B-Protocol
's	O
requirements	O
for	O
an	O
LDAP	B-Protocol
server	O
and	O
for	O
use	O
in	O
the	O
Netscape	B-Protocol
browser	I-Protocol
.	O
</s>
<s>
This	O
company	O
was	O
acquired	O
by	O
Oracle	B-Application
Corporation	I-Application
in	O
February	O
2006	O
.	O
</s>
<s>
Berkley	O
DB	O
1.x	O
releases	O
focused	O
on	O
managing	O
key/value	B-Data_Structure
data	O
storage	O
and	O
are	O
referred	O
to	O
as	O
"	O
Data	O
Store	O
"	O
(	O
DS	O
)	O
.	O
</s>
<s>
The	O
2.x	O
releases	O
added	O
a	O
locking	B-Operating_System
system	O
enabling	O
concurrent	O
access	O
to	O
data	O
.	O
</s>
<s>
The	O
3.x	O
releases	O
added	O
a	O
logging	O
system	O
for	O
transactions	B-General_Concept
and	O
recovery	O
,	O
called	O
"	O
Transactional	O
Data	O
Store	O
"	O
(	O
TDS	O
)	O
.	O
</s>
<s>
The	O
4.x	O
releases	O
added	O
the	O
ability	O
to	O
replicate	O
log	O
records	O
and	O
create	O
a	O
distributed	O
highly	O
available	O
single-master	O
multi-replica	O
database	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
's	O
evolution	O
has	O
sometimes	O
led	O
to	O
minor	O
API	B-Application
changes	O
or	O
log	O
format	O
changes	O
,	O
but	O
very	O
rarely	O
have	O
database	O
formats	O
changed	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
HA	O
supports	O
online	O
upgrades	O
from	O
one	O
version	O
to	O
the	O
next	O
by	O
maintaining	O
the	O
ability	O
to	O
read	O
and	O
apply	O
the	O
prior	O
release	O
's	O
log	O
records	O
.	O
</s>
<s>
Starting	O
with	O
the	O
6.0.21	O
(	O
Oracle	B-Application
12c	O
)	O
release	O
,	O
all	O
Berkeley	B-Language
DB	I-Language
products	O
are	O
licensed	O
under	O
the	O
GNU	B-Application
AGPL	I-Application
.	O
</s>
<s>
Previously	O
,	O
Berkeley	B-Language
DB	I-Language
was	O
redistributed	O
under	O
the	O
4-clause	O
BSD	B-Operating_System
license	I-Operating_System
(	O
before	O
version	O
2.0	O
)	O
,	O
and	O
the	O
Sleepycat	O
Public	O
License	O
,	O
which	O
is	O
an	O
OSI-approved	O
open-source	B-Application
license	O
as	O
well	O
as	O
an	O
FSF-approved	O
free	B-License
software	I-License
license	I-License
.	O
</s>
<s>
The	O
comprehensive	O
feature	O
along	O
with	O
the	O
licensing	O
terms	O
have	O
led	O
to	O
its	O
use	O
in	O
a	O
multitude	O
of	O
free	B-License
and	I-License
open-source	I-License
software	I-License
.	O
</s>
<s>
Those	O
who	O
do	O
not	O
wish	O
to	O
abide	O
by	O
the	O
terms	O
of	O
the	O
GNU	B-Application
AGPL	I-Application
,	O
or	O
use	O
an	O
older	O
version	O
with	O
the	O
Sleepycat	O
Public	O
License	O
,	O
have	O
the	O
option	O
of	O
purchasing	O
another	O
proprietary	B-Application
license	I-Application
for	O
redistribution	O
from	O
Oracle	B-Application
Corporation	I-Application
.	O
</s>
<s>
This	O
technique	O
is	O
called	O
dual	B-License
licensing	I-License
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
includes	O
compatibility	O
interfaces	O
for	O
some	O
historic	O
Unix	B-Application
database	O
libraries	O
:	O
dbm	B-General_Concept
,	O
ndbm	O
and	O
hsearch	O
(	O
a	O
System	B-Operating_System
V	I-Operating_System
and	O
POSIX	O
library	B-Library
for	O
creating	O
in-memory	O
hash	B-Algorithm
tables	I-Algorithm
)	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
has	O
an	O
architecture	O
notably	O
simpler	O
than	O
relational	B-Application
database	I-Application
management	I-Application
systems	I-Application
.	O
</s>
<s>
Like	O
SQLite	B-Language
and	O
LMDB	B-Language
,	O
it	O
is	O
not	O
based	O
on	O
a	O
server/client	B-Operating_System
model	O
,	O
and	O
does	O
not	O
provide	O
support	O
for	O
network	O
access	O
programs	O
access	O
the	O
database	O
using	O
in-process	O
API	B-Application
calls	O
.	O
</s>
<s>
Oracle	B-Application
added	O
support	O
for	O
SQL	O
in	O
11g	O
R2	O
release	O
based	O
on	O
the	O
popular	O
SQLite	B-Language
API	B-Application
by	O
including	O
a	O
version	O
of	O
SQLite	B-Language
in	O
Berkeley	B-Language
DB	I-Language
(	O
it	O
uses	O
Berkeley	B-Language
DB	I-Language
for	O
storage	O
)	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
puts	O
no	O
constraints	O
on	O
the	O
record	O
's	O
data	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
supports	O
database	O
features	O
such	O
as	O
ACID	O
transactions	B-General_Concept
,	O
fine-grained	O
locking	B-Operating_System
,	O
hot	O
backups	B-Protocol
and	O
replication	B-Architecture
.	O
</s>
<s>
The	O
name	O
"	O
Berkeley	B-Language
DB	I-Language
"	O
is	O
used	O
by	O
Oracle	B-Application
Corporation	I-Application
for	O
three	O
different	O
products	O
,	O
only	O
one	O
of	O
which	O
is	O
BDB	O
:	O
</s>
<s>
Notable	O
software	O
that	O
still	O
uses	O
Berkeley	B-Language
DB	I-Language
for	O
data	O
storage	O
include	O
:	O
</s>
<s>
Open	O
Source	O
operating	B-General_Concept
systems	I-General_Concept
,	O
and	O
languages	O
such	O
as	O
Perl	B-Language
and	O
Python	B-Language
still	O
support	O
old	O
BerkelyDB	O
interfaces	O
.	O
</s>
<s>
The	O
FreeBSD	B-Operating_System
and	O
OpenBSD	B-Operating_System
operating	B-General_Concept
systems	I-General_Concept
ship	O
Berkeley	B-Language
DB	I-Language
1.8x	O
to	O
support	O
the	O
dbopen( )	O
operating	B-General_Concept
system	I-General_Concept
call	O
used	O
by	O
password	O
programs	O
such	O
as	O
pwb_mkdb	O
.	O
</s>
<s>
Linux	O
operating	B-General_Concept
systems	I-General_Concept
including	O
those	O
based	O
on	O
Debian	O
and	O
Fedora	O
ship	O
Berkeley	B-Language
DB	I-Language
5.3	O
libraries	O
.	O
</s>
<s>
Berkeley	B-Language
DB	I-Language
V2.0	O
and	O
higher	O
is	O
available	O
under	O
a	O
dual	B-License
license	I-License
:	O
</s>
<s>
The	O
GNU	B-Application
AGPL	I-Application
v3	I-Application
.	O
</s>
<s>
Switching	O
the	O
open	O
source	O
license	O
in	O
2013	O
from	O
the	O
to	O
the	O
AGPL	B-Application
had	O
a	O
major	O
effect	O
on	O
open	B-Application
source	I-Application
software	I-Application
.	O
</s>
<s>
Since	O
BDB	O
is	O
a	O
library	B-Library
,	O
any	O
application	O
linking	O
to	O
it	O
must	O
be	O
under	O
an	O
AGPL-compatible	O
license	O
.	O
</s>
<s>
Many	O
open	O
source	O
applications	O
and	O
all	O
closed	B-Application
source	I-Application
applications	O
would	O
need	O
to	O
be	O
relicensed	O
to	O
become	O
AGPL-compatible	O
,	O
which	O
was	O
not	O
acceptable	O
to	O
many	O
developers	O
and	O
open	O
source	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
By	O
2013	O
there	O
were	O
many	O
alternatives	O
to	O
BDB	O
,	O
and	O
Debian	O
Linux	O
was	O
typical	O
in	O
their	O
decision	O
to	O
completely	O
phase	O
out	O
Berkeley	B-Language
DB	I-Language
,	O
with	O
a	O
preference	O
for	O
the	O
Lightning	B-Language
Memory-Mapped	I-Language
Database	I-Language
(	O
LMDB	B-Language
)	O
.	O
</s>
