<s>
The	O
Macintosh	B-Device
Quadra	I-Device
900	I-Device
is	O
a	O
personal	B-Device
computer	I-Device
designed	O
,	O
manufactured	O
,	O
and	O
sold	O
by	O
Apple	O
Computer	O
from	O
October	O
1991	O
to	O
May	O
1992	O
.	O
</s>
<s>
It	O
was	O
introduced	O
alongside	O
the	O
Quadra	B-Device
700	I-Device
as	O
the	O
first	O
computers	O
in	O
the	O
Quadra	B-Device
family	O
of	O
Macintosh	B-Device
computers	O
using	O
the	O
Motorola	B-Device
68040	I-Device
processor	O
.	O
</s>
<s>
The	O
Quadra	B-Device
900	I-Device
had	O
a	O
short	O
lifespan	O
;	O
it	O
was	O
discontinued	O
about	O
six	O
months	O
after	O
the	O
first	O
shipments	O
in	O
favor	O
of	O
the	O
more	O
powerful	O
Quadra	B-Device
950	I-Device
.	O
</s>
<s>
The	O
Quadra	B-Device
900	I-Device
was	O
more	O
expandable	O
than	O
the	O
Quadra	B-Device
700	I-Device
but	O
cost	O
US$	O
7,200	O
.	O
</s>
<s>
The	O
Quadra	B-Device
900	I-Device
could	O
be	O
upgraded	O
to	O
256megabytes	O
of	O
RAM	O
,	O
an	O
astronomical	O
amount	O
for	O
the	O
time	O
,	O
when	O
a	O
typical	O
midrange	O
system	O
would	O
come	O
equipped	O
with	O
2	O
–	O
4MB	O
.	O
</s>
<s>
The	O
high	O
RAM	O
and	O
storage	O
capacity	O
,	O
along	O
with	O
the	O
expandability	O
of	O
five	O
NuBus	B-Device
90	I-Device
slots	O
and	O
fast	O
25MHz	O
processor	O
,	O
made	O
it	O
a	O
very	O
useful	O
computer	O
for	O
scientific	O
or	O
design	O
work	O
.	O
</s>
<s>
The	O
mid-tower	O
case	O
design	O
features	O
a	O
single	O
5.25-inch	O
drive	B-Device
bay	I-Device
initially	O
intended	O
to	O
hold	O
a	O
tape	O
backup	O
drive	O
,	O
but	O
was	O
often	O
repurposed	O
to	O
hold	O
a	O
CD-ROM	O
or	O
SyQuest	O
drive	O
during	O
the	O
model	O
's	O
operational	O
lifespan	O
.	O
</s>
<s>
Featuring	O
16	O
slots	O
for	O
30-pin	O
SIMMs	O
(	O
installed	O
in	O
groups	O
of	O
four	O
)	O
,	O
Quadra	B-Device
900s	I-Device
with	O
full	O
complements	O
of	O
RAM	O
were	O
exceedingly	O
rare	O
due	O
to	O
the	O
high	O
cost	O
(	O
many	O
thousands	O
of	O
dollars	O
)	O
of	O
the	O
SIMMs	O
at	O
the	O
time	O
.	O
</s>
<s>
In	O
Secure	O
mode	O
,	O
the	O
floppy	O
drive	O
and	O
ADB	B-Device
port	I-Device
are	O
disabled	O
,	O
offering	O
a	O
degree	O
of	O
local	O
protection	O
.	O
</s>
<s>
System	B-Operating_System
7.0.1	I-Operating_System
was	O
included	O
and	O
supports	O
up	O
to	O
Mac	B-Operating_System
OS	I-Operating_System
8.1	I-Operating_System
.	O
</s>
<s>
It	O
is	O
the	O
earliest	O
Macintosh	B-Device
model	O
with	O
the	O
ability	O
to	O
run	O
Mac	B-Operating_System
OS	I-Operating_System
8	I-Operating_System
.	O
</s>
<s>
With	O
the	O
Power	O
Macintosh	B-Device
Upgrade	O
Card	O
installed	O
,	O
the	O
Quadra	B-Device
900	I-Device
runs	O
at	O
and	O
its	O
name	O
is	O
reported	O
in	O
the	O
System	O
Profiler	O
as	O
the	O
Power	O
Macintosh	B-Device
900	O
.	O
</s>
