<s>
The	O
Macintosh	B-Device
512K	I-Device
enhanced	O
(	O
512Ke	O
)	O
was	O
introduced	O
in	O
April	O
1986	O
as	O
a	O
cheaper	O
alternative	O
to	O
the	O
top-of-the-line	O
Macintosh	B-Device
Plus	I-Device
,	O
which	O
had	O
debuted	O
three	O
months	O
previously	O
.	O
</s>
<s>
It	O
is	O
the	O
same	O
as	O
the	O
Macintosh	B-Device
512K	I-Device
but	O
with	O
the	O
800K	O
disk	O
drive	O
and	O
128K	O
of	O
ROM	B-Device
used	O
in	O
the	O
Macintosh	B-Device
Plus	I-Device
.	O
</s>
<s>
But	O
like	O
the	O
Macintosh	B-Device
Plus	I-Device
,	O
in	O
1987	O
the	O
512Ke	O
adopted	O
the	O
standard	O
Apple	O
"	O
Platinum	O
"	O
color	O
,	O
as	O
well	O
as	O
the	O
same	O
case-front	O
design	O
as	O
the	O
Plus	O
(	O
without	O
the	O
name	O
)	O
,	O
though	O
keeping	O
its	O
original	O
rear	O
bucket	O
.	O
</s>
<s>
Later	O
in	O
its	O
lifespan	O
,	O
the	O
512Ke	O
was	O
discounted	O
and	O
offered	O
to	O
the	O
educational	O
market	O
,	O
badged	O
as	O
the	O
Macintosh	B-Device
ED	I-Device
(	O
M0001D	O
&	O
later	O
M0001ED	O
)	O
.	O
</s>
<s>
The	O
512Ke	O
shipped	O
with	O
the	O
original	O
short	O
Macintosh	O
Keyboard	O
,	O
but	O
the	O
extended	O
Macintosh	B-Device
Plus	I-Device
Keyboard	O
with	O
built-in	O
numeric	O
keypad	O
could	O
be	O
purchased	O
optionally	O
.	O
</s>
<s>
Although	O
the	O
512Ke	O
includes	O
the	O
same	O
128K	O
ROMs	O
and	O
800K	O
disk	O
drive	O
as	O
the	O
Mac	B-Device
Plus	I-Device
,	O
the	O
512Ke	O
retains	O
the	O
same	O
port	O
connectors	O
as	O
the	O
original	O
Mac	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
512Ke	O
users	O
 '	O
only	O
hard	O
disk	O
option	O
is	O
the	O
slower	O
,	O
floppy-port-based	O
Hard	B-Device
Disk	I-Device
20	I-Device
,	O
or	O
similar	O
products	O
for	O
the	O
serial	O
port	O
,	O
even	O
though	O
the	O
512Ke	O
ROMs	O
contain	O
the	O
"	O
SCSI	B-Architecture
Manager	O
"	O
software	O
that	O
enables	O
the	O
use	O
of	O
faster	O
SCSI	B-Architecture
hard	O
disks	O
(	O
because	O
the	O
ROMs	O
are	O
the	O
same	O
as	O
the	O
ones	O
used	O
in	O
the	O
Mac	B-Device
Plus	I-Device
,	O
which	O
does	O
have	O
a	O
SCSI	B-Architecture
port	O
)	O
.	O
</s>
<s>
Apple	O
did	O
point	O
users	O
to	O
certain	O
third-party	O
products	O
which	O
could	O
be	O
added	O
to	O
the	O
512Ke	O
to	O
provide	O
a	O
SCSI	B-Architecture
port	O
(	O
Apple	O
copied	O
the	O
MacSCSI	O
design	O
in	O
the	O
Mac	B-Device
Plus	I-Device
logic	B-Device
board	I-Device
)	O
.	O
</s>
<s>
A	O
Macintosh	B-Device
512K	I-Device
could	O
be	O
upgraded	O
to	O
a	O
512Ke	O
by	O
purchasing	O
and	O
installing	O
Apple	O
's	O
$299	O
Macintosh	B-Device
Plus	I-Device
Disk	O
Drive	O
Kit	O
.	O
</s>
<s>
One	O
further	O
upgrade	O
made	O
by	O
Apple	O
replaced	O
the	O
logic	B-Device
board	I-Device
and	O
the	O
rear	O
case	O
(	O
to	O
accommodate	O
the	O
different	O
port	O
configuration	O
)	O
with	O
those	O
of	O
the	O
Macintosh	B-Device
Plus	I-Device
,	O
providing	O
built-in	O
SCSI	B-Architecture
functionality	O
and	O
up	O
to	O
4	O
MB	O
RAM	B-Architecture
.	O
</s>
<s>
Because	O
Apple	O
's	O
official	O
upgrades	O
were	O
costly	O
,	O
many	O
third-party	O
manufacturers	O
offered	O
add-on	O
SCSI	B-Architecture
cards	O
,	O
as	O
well	O
as	O
RAM	B-Architecture
upgrades	O
,	O
to	O
achieve	O
the	O
same	O
functionality	O
.	O
</s>
<s>
The	O
new	O
ROM	B-Device
allowed	O
the	O
computer	O
to	O
run	O
much	O
newer	O
system	O
and	O
application	O
software	O
;	O
though	O
it	O
loaded	O
more	O
data	O
into	O
RAM	B-Architecture
,	O
it	O
only	O
slightly	O
decreased	O
the	O
amount	O
of	O
available	O
memory	O
–	O
by	O
1.5	O
KB	O
–	O
leaving	O
well	O
over	O
370	O
KB	O
available	O
for	O
applications	O
.	O
</s>
<s>
After	O
June	O
1986	O
,	O
the	O
512Ke	O
shipped	O
with	O
System	O
3.2	B-Application
.	O
</s>
<s>
After	O
it	O
was	O
discontinued	O
,	O
Apple	O
changed	O
the	O
recommended	O
OS	O
for	O
the	O
512Ke	O
to	O
System	O
4.1	B-Application
.	O
</s>
