<s>
MachTen	B-Operating_System
is	O
a	O
Unix-like	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
from	O
Tenon	O
Intersystems	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
4.4BSD	B-Operating_System
and	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
,	O
and	O
features	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
and	O
GNU	B-Operating_System
programming	O
tools	O
.	O
</s>
<s>
It	O
runs	O
only	O
as	O
a	O
classic	B-Application
Mac	I-Application
OS	I-Application
application	O
program	O
(	O
in	O
a	O
virtual	B-Architecture
machine	I-Architecture
)	O
on	O
Macintosh	B-Device
computers	O
.	O
</s>
<s>
MachTen	B-Operating_System
development	O
started	O
in	O
1989	O
,	O
culminating	O
in	O
the	O
first	O
release	O
in	O
1991	O
.	O
</s>
<s>
The	O
Professional	O
MachTen	B-Operating_System
branch	O
,	O
intended	O
for	O
Motorola	O
68000-based	O
Macintoshes	B-Device
,	O
ended	O
with	O
release	O
2.3	O
.	O
</s>
<s>
The	O
Power	O
MachTen	B-Operating_System
branch	O
,	O
which	O
is	O
Power	B-Device
Macintosh	I-Device
compatible	O
,	O
lacks	O
some	O
of	O
the	O
features	O
of	O
Professional	O
MachTen	B-Operating_System
(	O
including	O
true	O
virtual	B-Architecture
and	O
protected	B-General_Concept
memory	I-General_Concept
models	O
)	O
,	O
but	O
takes	O
full	O
advantage	O
of	O
the	O
PowerPC	B-Architecture
processor	I-Architecture
and	O
is	O
compatible	O
with	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
through	O
its	O
final	O
version	O
,	O
4.1.4	O
.	O
</s>
<s>
MachTen	B-Operating_System
is	O
no	O
longer	O
developed	O
,	O
and	O
is	O
functionally	O
superseded	O
by	O
macOS	B-Application
.	O
</s>
