<s>
Tkrzw	O
is	O
a	O
library	B-Library
of	O
routines	O
for	O
managing	O
key-value	B-Data_Structure
databases	I-Data_Structure
.	O
</s>
<s>
Tokyo	B-Application
Cabinet	I-Application
was	O
sponsored	O
by	O
the	O
Japanese	O
social	O
networking	O
site	O
Mixi	O
,	O
and	O
was	O
a	O
multithreaded	O
embedded	B-Application
database	I-Application
manager	O
and	O
was	O
announced	O
by	O
its	O
authors	O
as	O
"	O
a	O
modern	O
implementation	O
of	O
DBM	B-General_Concept
"	O
.	O
</s>
<s>
Kyoto	O
Cabinet	O
is	O
the	O
designated	O
successor	O
of	O
Tokyo	B-Application
Cabinet	I-Application
,	O
while	O
Tkrzw	O
is	O
a	O
recommended	O
successor	O
of	O
Kyoto	O
Cabinet	O
.	O
</s>
<s>
Tokyo	B-Application
Cabinet	I-Application
features	O
on-disk	O
B+	O
trees	O
and	O
hash	B-Algorithm
tables	I-Algorithm
for	O
key-value	B-Data_Structure
storage	O
,	O
with	O
"	O
some	O
"	O
support	O
for	O
transactions	B-General_Concept
.	O
</s>
