<s>
The	O
MAC-16	O
(	O
or	O
LEC-16	O
)	O
was	O
a	O
16-bit	B-Device
minicomputer	B-Architecture
introduced	O
in	O
1969	O
by	O
Lockheed	O
Electronics	O
.	O
</s>
<s>
One	O
main	O
selling	O
point	O
of	O
the	O
MAC-16	O
was	O
a	O
dedicated	O
context	B-Operating_System
switching	I-Operating_System
system	O
that	O
completed	O
operations	O
in	O
two	O
machine	O
cycles	O
.	O
</s>
<s>
The	O
MAC-16	O
was	O
designed	O
to	O
support	O
various	O
high-performance	O
military	O
and	O
civilian	O
roles	O
,	O
and	O
thus	O
spent	O
a	O
considerable	O
amount	O
of	O
time	O
on	O
guaranteeing	O
high	O
speed	O
context	B-Operating_System
switching	I-Operating_System
to	O
support	O
real-time	B-General_Concept
computing	I-General_Concept
.	O
</s>
<s>
A	O
switch	O
to	O
and	O
from	O
an	O
interrupt	B-General_Concept
handler	I-General_Concept
took	O
only	O
2	O
cycles	O
.	O
</s>
<s>
The	O
original	O
MAC-16	O
operated	O
with	O
a	O
1μS	O
cycle	O
time	O
using	O
core	B-General_Concept
memory	I-General_Concept
and	O
TTL	O
integrated	O
circuits	O
.	O
</s>
<s>
Like	O
any	O
machine	O
based	O
on	O
a	O
16-bit	B-Device
instruction	B-General_Concept
register	I-General_Concept
,	O
the	O
original	O
MAC-16	O
was	O
able	O
to	O
address	O
up	O
to	O
64kilo-words	O
(	O
kW	O
,	O
128kB	O
)	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
At	O
the	O
time	O
,	O
RAM	B-Architecture
was	O
provided	O
in	O
the	O
form	O
of	O
hand-wired	O
core	B-General_Concept
memory	I-General_Concept
,	O
which	O
cost	O
about	O
$1	O
per	O
word	O
.	O
</s>
<s>
Most	O
MAC-16	O
machines	O
thus	O
featured	O
considerably	O
less	O
than	O
64kW	O
,	O
and	O
8kW	O
systems	O
were	O
common	O
as	O
this	O
was	O
all	O
that	O
was	O
needed	O
to	O
support	O
a	O
Fortran	B-Application
compiler	O
.	O
</s>
<s>
One	O
well-known	O
role	O
for	O
the	O
MAC-16	O
was	O
Lockheed	O
's	O
winning	O
entry	O
for	O
the	O
Federal	O
Aviation	O
Administration	O
's	O
"	O
ARTS	O
II	O
"	O
air-traffic	B-Application
control	I-Application
system	O
.	O
</s>
