<s>
Multics	B-Operating_System
Emacs	I-Operating_System
is	O
an	O
early	O
implementation	O
of	O
the	O
Emacs	B-Application
text	B-Application
editor	I-Application
.	O
</s>
<s>
It	O
was	O
written	O
in	O
Maclisp	B-Language
by	O
Bernard	O
Greenberg	O
at	O
Honeywell	O
's	O
Cambridge	O
Information	O
Systems	O
Lab	O
in	O
1978	O
,	O
as	O
a	O
successor	O
to	O
the	O
original	O
1976	O
TECO	B-Application
implementation	O
of	O
Emacs	B-Application
and	O
a	O
precursor	O
of	O
later	O
GNU	B-Application
Emacs	I-Application
.	O
</s>
<s>
It	O
has	O
been	O
claimed	O
to	O
be	O
the	O
first	O
version	O
of	O
Emacs	B-Application
to	O
be	O
written	O
in	O
the	O
Lisp	B-Language
programming	I-Language
language	I-Language
,	O
although	O
the	O
same	O
claim	O
has	O
also	O
been	O
made	O
for	O
the	O
Lisp	B-Operating_System
Machine	I-Operating_System
editors	O
EINE	B-Operating_System
and	I-Operating_System
ZWEI	I-Operating_System
,	O
also	O
written	O
in	O
the	O
late	O
1970s	O
.	O
</s>
<s>
As	O
well	O
as	O
the	O
editor	O
itself	O
being	O
written	O
in	O
Lisp	B-Language
,	O
user-supplied	O
extensions	O
were	O
also	O
written	O
in	O
Lisp	B-Language
.	O
</s>
<s>
The	O
choice	O
of	O
Lisp	B-Language
provided	O
more	O
extensibility	O
than	O
ever	O
before	O
,	O
and	O
has	O
been	O
followed	O
by	O
most	O
subsequent	O
Emacs	B-Application
implementations	O
.	O
</s>
<s>
Rather	O
than	O
using	O
TECO	B-Application
's	O
gap	B-Data_Structure
buffer	I-Data_Structure
representation	O
for	O
the	O
text	O
being	O
edited	O
,	O
it	O
used	O
a	O
doubly	B-Data_Structure
linked	I-Data_Structure
list	I-Data_Structure
of	O
lines	O
of	O
text	O
.	O
</s>
