<s>
Tabular	B-Protocol
Data	I-Protocol
Stream	I-Protocol
(	O
TDS	O
)	O
is	O
an	O
application	B-Application
layer	I-Application
protocol	O
used	O
to	O
transfer	O
data	O
between	O
a	O
database	B-Application
server	I-Application
and	O
a	O
client	B-Protocol
.	O
</s>
<s>
It	O
was	O
initially	O
designed	O
and	O
developed	O
by	O
Sybase	B-Application
Inc	O
.	O
for	O
their	O
Sybase	B-Application
SQL	I-Application
Server	I-Application
relational	B-Application
database	I-Application
engine	O
in	O
1984	O
,	O
and	O
later	O
by	O
Microsoft	O
in	O
Microsoft	B-Application
SQL	I-Application
Server	I-Application
.	O
</s>
<s>
During	O
the	O
early	O
development	O
of	O
Sybase	B-Application
SQL	I-Application
Server	I-Application
,	O
the	O
developers	O
at	O
Sybase	B-Application
perceived	O
the	O
lack	O
of	O
a	O
commonly	O
accepted	O
application	O
level	O
protocol	O
to	O
transfer	O
data	O
between	O
a	O
database	B-Application
server	I-Application
and	O
its	O
client	B-Protocol
.	O
</s>
<s>
In	O
order	O
to	O
encourage	O
the	O
use	O
of	O
its	O
products	O
,	O
Sybase	B-Application
promoted	O
the	O
use	O
of	O
a	O
flexible	O
pair	O
of	O
libraries	B-Library
,	O
called	O
netlib	O
and	O
db-lib	O
,	O
to	O
implement	O
standard	O
SQL	B-Language
.	O
</s>
<s>
While	O
netlib	O
's	O
job	O
is	O
to	O
ferry	O
data	O
between	O
the	O
two	O
computers	O
through	O
the	O
underlying	O
network	O
protocol	O
,	O
db-lib	O
provides	O
an	O
API	O
to	O
the	O
client	B-Protocol
program	I-Protocol
,	O
and	O
communicates	O
with	O
the	O
server	O
via	O
netlib	O
.	O
</s>
<s>
db-lib	O
sends	O
to	O
the	O
server	O
a	O
structured	O
stream	O
of	O
bytes	O
meant	O
for	O
tables	O
of	O
data	O
,	O
hence	O
a	O
Tabular	B-Protocol
Data	I-Protocol
Stream	I-Protocol
.	O
</s>
<s>
blk	O
provides	O
,	O
like	O
db-lib	O
,	O
an	O
API	O
to	O
the	O
client	B-Protocol
programs	I-Protocol
and	O
communicates	O
with	O
the	O
server	O
via	O
netlib	O
.	O
</s>
<s>
In	O
1990	O
Sybase	B-Application
entered	O
into	O
a	O
technology-sharing	O
agreement	O
with	O
Microsoft	O
which	O
resulted	O
in	O
Microsoft	O
marketing	O
its	O
own	O
SQL	B-Language
Server	O
—	O
Microsoft	B-Application
SQL	I-Application
Server	I-Application
—	O
based	O
on	O
Sybase	B-Application
's	O
code	O
.	O
</s>
<s>
Microsoft	O
kept	O
the	O
db-lib	O
API	O
and	O
added	O
ODBC	B-Application
.	O
</s>
<s>
At	O
about	O
the	O
same	O
time	O
,	O
Sybase	B-Application
introduced	O
a	O
more	O
powerful	O
successor	O
to	O
db-lib	O
,	O
called	O
ct-lib	O
,	O
and	O
called	O
the	O
pair	O
Open	O
Client	B-Protocol
.	O
</s>
<s>
The	O
TDS	O
protocol	O
comes	O
in	O
several	O
varieties	O
,	O
most	O
of	O
which	O
had	O
not	O
been	O
openly	O
documented	O
because	O
they	O
were	O
regarded	O
as	O
proprietary	B-Application
technology	I-Application
.	O
</s>
<s>
The	O
exception	O
was	O
TDS	O
5.0	O
,	O
used	O
exclusively	O
by	O
Sybase	B-Application
,	O
for	O
which	O
documentation	O
is	O
available	O
from	O
Sybase	B-Application
.	O
</s>
<s>
The	O
FreeTDS	B-Language
team	O
has	O
developed	O
a	O
free	O
native-library	O
implementation	O
of	O
the	O
TDS	O
protocol	O
,	O
licensed	O
under	O
the	O
LGPL	B-Application
license	I-Application
.	O
</s>
<s>
WireShark	B-Language
has	O
a	O
protocol	O
decoder	O
for	O
TDS	O
.	O
</s>
<s>
Oracle	B-Application
Corporation	I-Application
provides	O
Oracle	B-Application
Net	I-Application
-	O
software	O
analogous	O
to	O
TDS	O
.	O
</s>
