<s>
The	O
Apple	O
Hard	B-Device
Disk	I-Device
20SC	I-Device
is	O
Apple	O
's	O
first	O
SCSI	B-Architecture
based	O
hard	O
drive	O
for	O
the	O
Apple	B-Device
II	I-Device
family	O
as	O
well	O
as	O
the	O
Macintosh	B-Device
and	O
other	O
third	O
party	O
computers	O
using	O
an	O
industry	O
standard	O
SCSI	B-Architecture
interface	O
.	O
</s>
<s>
Released	O
in	O
September	O
1986	O
along	O
with	O
the	O
Apple	B-Device
IIGS	I-Device
(	O
which	O
required	O
an	O
optional	O
SCSI	B-Architecture
interface	O
card	O
to	O
use	O
it	O
)	O
,	O
it	O
debuted	O
over	O
9	O
months	O
after	O
the	O
introduction	O
of	O
the	O
Macintosh	B-Device
Plus	I-Device
,	O
the	O
first	O
to	O
include	O
Apple	O
's	O
SCSI	B-Architecture
interface	O
.	O
</s>
<s>
The	O
20SC	O
originally	O
contained	O
a	O
half	O
height	O
5.25	O
"	O
Seagate	O
ST-225N	O
20MB	O
SCSI	B-Architecture
hard	O
drive	O
,	O
but	O
was	O
later	O
manufactured	O
with	O
a	O
full-height	O
3.5	O
"	O
MiniScribe	O
8425SA	O
20MB	O
SCSI	B-Architecture
hard	O
drive	O
.	O
</s>
<s>
The	O
latter	O
drive	O
was	O
the	O
same	O
size	O
as	O
the	O
drive	O
inside	O
the	O
Macintosh	B-Device
Hard	O
Disk	O
20	O
,	O
but	O
10	O
to	O
15	O
MB	O
over	O
what	O
had	O
previously	O
been	O
offered	O
by	O
Apple	O
for	O
the	O
II	O
family	O
.	O
</s>
<s>
The	O
same	O
drive	O
mechanism	O
would	O
also	O
be	O
offered	O
6	O
months	O
later	O
as	O
a	O
built-in	O
drive	O
option	O
on	O
the	O
Macintosh	B-Device
II	I-Device
and	O
SE	B-Device
.	O
</s>
<s>
It	O
had	O
two	O
standard	O
Centronics	O
50-pin	O
connectors	O
,	O
one	O
for	O
the	O
System	O
and	O
one	O
for	O
daisy-chaining	B-Application
additional	O
SCSI	B-Architecture
devices	O
and	O
a	O
SCSI	B-Architecture
ID	O
selection	O
switch	O
.	O
</s>
<s>
An	O
external	O
terminator	O
was	O
required	O
if	O
it	O
was	O
the	O
only	O
SCSI	B-Architecture
device	O
connected	O
.	O
</s>
<s>
While	O
the	O
transfer	O
rates	O
were	O
significantly	O
higher	O
due	O
to	O
the	O
faster	O
SCSI	B-Architecture
bus	O
technology	O
,	O
the	O
actual	O
transfer	O
rate	O
varied	O
from	O
computer	O
to	O
computer	O
thanks	O
to	O
different	O
SCSI	B-Architecture
implementation	O
based	O
on	O
developing	O
industry	O
standards	O
.	O
</s>
<s>
Notably	O
,	O
it	O
was	O
the	O
only	O
Snow	O
White	O
product	O
to	O
use	O
the	O
Macintosh	B-Device
beige	O
color	O
and	O
one	O
of	O
the	O
few	O
Apple	O
products	O
to	O
be	O
introduced	O
in	O
two	O
different	O
colors	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Since	O
the	O
Apple	B-Device
IIGS	I-Device
was	O
the	O
first	O
Apple	O
product	O
to	O
debut	O
in	O
the	O
new	O
gray	O
color	O
they	O
called	O
Platinum	O
,	O
the	O
20SC	O
had	O
to	O
both	O
match	O
it	O
and	O
the	O
beige	O
color	O
of	O
the	O
Macintosh	B-Device
Plus	I-Device
,	O
which	O
it	O
is	O
designed	O
to	O
sit	O
perfectly	O
beneath	O
.	O
</s>
