<s>
The	O
Directory	B-Protocol
Assistance	I-Protocol
Service	I-Protocol
(	O
DAS	O
)	O
is	O
an	O
obsolete	O
protocol	O
and	O
service	O
for	O
accessing	O
X.500	B-Protocol
directory	I-Protocol
services	O
.	O
</s>
<s>
means	O
for	O
clients	O
to	O
access	O
X.500	B-Protocol
directory	I-Protocol
services	O
via	O
a	O
split-Directory	O
User	O
Agent	O
model	O
.	O
</s>
<s>
The	O
directory	O
user	O
would	O
interact	O
with	O
the	O
DA-client	O
,	O
the	O
DA-Client	O
would	O
communicate	O
with	O
the	O
Directory	O
Assistant	O
using	O
the	O
DA	O
protocol	O
,	O
and	O
the	O
Directory	O
Assistant	O
would	O
communicate	O
with	O
the	O
Directory	O
Service	O
using	O
the	O
X.500	B-Protocol
Directory	I-Protocol
Access	O
Protocol	O
(	O
DAP	O
)	O
.	O
</s>
<s>
The	O
Directory	B-Protocol
Assistance	I-Protocol
Service	I-Protocol
was	O
created	O
in	O
1990	O
by	O
Marshall	O
Rose	O
while	O
at	O
Performance	O
Systems	O
International	O
,	O
Inc.	O
,	O
and	O
formally	O
specified	O
in	O
RFC	O
1202	O
(	O
published	O
in	O
1991	O
)	O
.	O
</s>
<s>
These	O
and	O
related	O
efforts	O
,	O
such	O
as	O
DIXIE	B-Protocol
,	O
led	O
to	O
the	O
development	O
of	O
the	O
Lightweight	B-Protocol
Directory	I-Protocol
Access	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
LDAP	B-Protocol
replaced	O
the	O
Directory	B-Protocol
Assistance	I-Protocol
Service	I-Protocol
.	O
</s>
