<s>
The	O
AT&T	B-Device
UNIX	I-Device
PC	I-Device
is	O
a	O
Unix	B-Application
desktop	B-Device
computer	I-Device
originally	O
developed	O
by	O
Convergent	O
Technologies	O
(	O
later	O
acquired	O
by	O
Unisys	O
)	O
,	O
and	O
marketed	O
by	O
AT&T	O
Information	O
Systems	O
in	O
the	O
mid	O
-	O
to	O
late-1980s	O
.	O
</s>
<s>
The	O
system	O
was	O
codenamed	O
"	O
Safari	O
4	O
"	O
and	O
is	O
also	O
known	O
as	O
the	O
PC	O
7300	O
,	O
and	O
often	O
dubbed	O
the	O
"	O
3B1	B-Device
"	O
.	O
</s>
<s>
Despite	O
the	O
latter	O
name	O
,	O
the	O
system	O
had	O
little	O
in	O
common	O
with	O
T	O
's	O
line	O
of	O
3B	B-Device
series	I-Device
computers	I-Device
.	O
</s>
<s>
The	O
initial	O
PC	O
7300	O
model	O
offered	O
a	O
modest	O
512KB	O
of	O
memory	O
and	O
a	O
small	O
,	O
low	O
performance	O
10MB	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
This	O
model	O
,	O
although	O
progressive	O
in	O
offering	O
a	O
Unix	B-Application
system	I-Application
for	O
desktop	O
office	O
operation	O
,	O
was	O
underpowered	O
and	O
produced	O
considerable	O
fan	O
and	O
drive	O
bearing	O
noise	O
even	O
when	O
idling	O
.	O
</s>
<s>
An	O
enhanced	O
model	O
,	O
"	O
3B/1	O
"	O
,	O
was	O
introduced	O
in	O
October	O
1985	O
starting	O
at	O
.	O
</s>
<s>
The	O
cover	O
was	O
redesigned	O
to	O
accommodate	O
a	O
full-height	B-Device
67	O
MB	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
British	O
Olivetti	O
released	O
the	O
"	O
Olivetti	O
AT&T	B-Device
3B1	I-Device
Computer	O
"	O
in	O
Europe	O
.	O
</s>
<s>
The	O
operating	O
system	O
is	O
based	O
on	O
Unix	B-Operating_System
System	I-Operating_System
V	I-Operating_System
Release	O
2	O
,	O
with	O
extensions	O
from	O
4.1	O
and	O
4.2	O
BSD	B-Operating_System
,	O
System	B-Operating_System
V	I-Operating_System
Release	I-Operating_System
3	I-Operating_System
and	O
Convergent	O
Technologies	O
.	O
</s>
<s>
The	O
UNIX	B-Device
PC	I-Device
has	O
three	O
proprietary	O
S4BUS	O
slots	O
for	O
expansion	O
cards	O
:	O
</s>
<s>
DOS-73	O
8086	B-General_Concept
co-processor	B-General_Concept
card	O
running	O
at	O
8	O
MHz	O
,	O
Hercules	O
graphics-compatible	O
,	O
with	O
512	O
KB	O
RAM	B-Architecture
,	O
an	O
RS-232	O
COM2	O
port	O
and	O
optional	O
8087	B-Device
math	B-General_Concept
co-processor	I-General_Concept
.	O
</s>
<s>
Mouse	B-Device
,	O
floppy	B-Device
,	O
modem	B-Application
(	O
on	O
COM1	O
)	O
,	O
and	O
printer	O
are	O
shared	O
in	O
a	O
DOS	O
session	O
.	O
</s>
<s>
RAM	B-Architecture
could	O
be	O
added	O
using	O
512	O
KB	O
RAM	B-Architecture
or	O
2	O
MB	O
RAM	B-Architecture
cards	O
,	O
up	O
to	O
a	O
maximum	O
of	O
4	O
MB	O
(	O
2	O
MB	O
on	O
the	O
motherboard	O
and	O
2	O
MB	O
on	O
expansion	O
cards	O
)	O
.	O
</s>
<s>
EIA/RAM	O
combo	O
cards	O
contained	O
extra	O
RAM	B-Architecture
(	O
512	O
KB	O
,	O
1	O
MB	O
,	O
or	O
1.5	O
MB	O
)	O
and	O
two	O
RS-232	O
serial	B-Protocol
ports	I-Protocol
.	O
</s>
<s>
This	O
was	O
an	O
option	O
of	O
the	O
"	O
Integrated	O
Solution	O
"	O
package	O
for	O
the	O
AT&T	O
System	O
25	O
PBX	B-Device
where	O
the	O
UNIX	B-Device
PC	I-Device
served	O
as	O
the	O
"	O
Master	O
Controller	O
"	O
.	O
</s>
<s>
Floppy	B-Device
Tape	O
card	O
provided	O
interface	O
for	O
23	O
MB	O
MFM	B-Protocol
Tape	O
Cartridge	O
Drive	O
(	O
e.g.	O
</s>
<s>
was	O
a	O
public	B-Application
domain	I-Application
software	I-Application
repository	O
provided	O
by	O
AT&T	O
and	O
accessible	O
via	O
dialup	O
UUCP	B-Protocol
.	O
</s>
