<s>
Zmacs	B-Operating_System
is	O
one	O
of	O
the	O
many	O
variants	O
of	O
the	O
Emacs	B-Application
text	B-Application
editor	I-Application
.	O
</s>
<s>
Zmacs	B-Operating_System
was	O
written	O
for	O
the	O
MIT	O
Lisp	B-Operating_System
machine	I-Operating_System
and	O
runs	O
on	O
its	O
descendants	O
(	O
Symbolics	O
Genera	O
,	O
LMI	O
Lambda	O
,	O
TI	B-Language
Explorer	I-Language
)	O
.	O
</s>
<s>
Zmacs	B-Operating_System
is	O
written	O
in	O
Lisp	B-Language
Machine	I-Language
Lisp	I-Language
(	O
called	O
ZetaLisp	B-Language
on	O
Symbolics	O
Lisp	B-Operating_System
Machines	I-Operating_System
)	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
the	O
ZWEI	B-Operating_System
programming	O
substrate	O
,	O
which	O
stands	O
for	O
"	O
Zwei	B-Operating_System
Was	O
EINE	B-Operating_System
Initially	O
"	O
;	O
Zwei	B-Operating_System
was	O
a	O
collection	O
of	O
routines	O
which	O
could	O
be	O
used	O
to	O
easily	O
implement	O
other	O
programs	O
,	O
like	O
the	O
Symbolics	O
mail	O
program	O
,	O
Zmail	O
.	O
</s>
<s>
A	O
distinctive	O
feature	O
of	O
Zmacs	B-Operating_System
,	O
which	O
can	O
also	O
be	O
found	O
in	O
Hemlock	B-Application
and	O
LispWorks	B-Language
,	O
is	O
that	O
commands	O
look	O
like	O
instead	O
of	O
as	O
modern	O
Emacsen	B-Application
,	O
like	O
GNU	B-Application
Emacs	I-Application
,	O
generally	O
format	O
commands	O
.	O
</s>
<s>
Zmacs	B-Operating_System
also	O
supports	O
buffers	O
and	O
modes	O
.	O
</s>
<s>
Zmacs	B-Operating_System
also	O
uses	O
the	O
window	O
system	O
of	O
the	O
Lisp	B-Operating_System
Machine	I-Operating_System
with	O
support	O
for	O
mouse	O
and	O
windows	O
.	O
</s>
<s>
Zmacs	B-Operating_System
supports	O
unlimited	O
backup	O
of	O
files	O
,	O
since	O
the	O
file	O
system	O
of	O
the	O
Lisp	B-Operating_System
Machine	I-Operating_System
supports	O
file	O
versions	O
.	O
</s>
<s>
It	O
is	O
not	O
compatible	O
with	O
GNU	B-Application
Emacs	I-Application
and	O
its	O
Emacs	B-Application
Lisp	O
.	O
</s>
