<s>
The	O
PERQ	B-Device
,	O
also	O
referred	O
to	O
as	O
the	O
Three	B-Device
Rivers	I-Device
PERQ	I-Device
or	O
ICL	B-Device
PERQ	I-Device
,	O
was	O
a	O
pioneering	O
workstation	B-Device
computer	I-Device
produced	O
in	O
the	O
late	O
1970s	O
through	O
the	O
early	O
1980s	O
.	O
</s>
<s>
It	O
was	O
the	O
first	O
commercially	O
produced	O
personal	B-Device
workstation	I-Device
with	O
a	O
Graphical	B-Application
User	I-Application
Interface	I-Application
.	O
</s>
<s>
The	O
design	O
was	O
heavily	O
influenced	O
by	O
the	O
original	O
workstation	B-Device
computer	I-Device
,	O
the	O
Xerox	B-Device
Alto	I-Device
,	O
which	O
was	O
never	O
commercially	O
produced	O
.	O
</s>
<s>
The	O
origin	O
of	O
the	O
name	O
"	O
PERQ	B-Device
"	O
was	O
chosen	O
both	O
as	O
an	O
acronym	O
of	O
"	O
Pascal	B-Application
Engine	O
that	O
Runs	O
Quicker	O
,	O
"	O
and	O
to	O
evoke	O
the	O
word	O
perquisite	O
commonly	O
called	O
perks	O
,	O
that	O
is	O
employee	O
additional	O
benefits	O
.	O
</s>
<s>
The	O
workstation	B-Device
was	O
conceived	O
by	O
six	O
former	O
Carnegie	O
Mellon	O
University	O
alumni	O
and	O
employees	O
,	O
Brian	O
S	O
.	O
Rosen	O
,	O
James	O
R	O
.	O
Teter	O
,	O
William	O
H	O
.	O
Broadley	O
,	O
J	O
.	O
Stanley	O
Kriz	O
,	O
Raj	O
Reddy	O
and	O
Paul	O
G	O
.	O
Newbury	O
,	O
who	O
formed	O
the	O
startup	O
Three	O
Rivers	O
Computer	O
Corporation	O
(	O
3RCC	O
)	O
in	O
1974	O
.	O
</s>
<s>
Brian	O
Rosen	O
also	O
worked	O
at	O
Xerox	O
PARC	O
on	O
the	O
Dolphin	O
workstation	B-Device
.	O
</s>
<s>
The	O
PERQ	B-Device
was	O
used	O
in	O
a	O
number	O
of	O
academic	O
research	O
projects	O
in	O
the	O
UK	O
during	O
the	O
1980s	O
.	O
</s>
<s>
3RCC	O
was	O
renamed	O
PERQ	B-Device
System	O
Corporation	O
in	O
1984	O
.	O
</s>
<s>
It	O
went	O
out	O
of	O
business	O
in	O
1986	O
,	O
largely	O
due	O
to	O
competition	O
from	O
other	O
workstation	B-Device
manufacturers	O
such	O
as	O
Sun	O
Microsystems	O
,	O
Apollo	O
Computer	O
and	O
Silicon	O
Graphics	O
.	O
</s>
<s>
The	O
PERQ	B-Device
CPU	B-General_Concept
was	O
a	O
microcoded	B-Device
discrete	B-General_Concept
logic	I-General_Concept
design	O
,	O
rather	O
than	O
a	O
microprocessor	B-Architecture
.	O
</s>
<s>
It	O
was	O
based	O
around	O
74S181	O
bit-slice	B-General_Concept
ALUs	I-General_Concept
and	O
an	O
Am2910	B-General_Concept
microcode	B-Device
sequencer	O
.	O
</s>
<s>
The	O
PERQ	B-Device
CPU	B-General_Concept
was	O
unusual	O
in	O
having	O
20-bit	O
wide	O
registers	B-General_Concept
and	O
a	O
writable	O
control	B-General_Concept
store	I-General_Concept
(	O
WCS	O
)	O
,	O
allowing	O
the	O
microcode	B-Device
to	O
be	O
redefined	O
.	O
</s>
<s>
The	O
CPU	B-General_Concept
had	O
a	O
microinstruction	B-Device
cycle	O
period	O
of	O
170	O
ns	O
(	O
5.88MHz	O
)	O
.	O
</s>
<s>
The	O
original	O
PERQ	B-Device
(	O
also	O
known	O
as	O
the	O
PERQ	B-Device
1	O
)	O
,	O
launched	O
in	O
1980	O
,	O
was	O
housed	O
in	O
a	O
pedestal-type	O
cabinet	O
with	O
a	O
brown	O
fascia	O
and	O
an	O
8-inch	B-Device
floppy	I-Device
disk	O
drive	O
mounted	O
horizontally	O
at	O
the	O
top	O
.	O
</s>
<s>
The	O
PERQ	B-Device
1	O
CPU	B-General_Concept
had	O
a	O
WCS	O
comprising	O
4k	O
words	O
of	O
48-bit	O
microcode	B-Device
memory	O
.	O
</s>
<s>
The	O
later	O
PERQ	B-Device
1A	O
CPU	B-General_Concept
extended	O
the	O
WCS	O
to	O
16k	O
words	O
.	O
</s>
<s>
The	O
PERQ	B-Device
1	O
could	O
be	O
configured	O
with	O
256	O
kB	O
,	O
1MB	O
or	O
2	O
MB	O
of	O
64-bit-wide	O
RAM	B-Architecture
(	O
accessed	O
via	O
a	O
16-bit	O
bus	O
)	O
,	O
a	O
12	O
or	O
24	O
MB	O
,	O
14-inch	O
Shugart	O
SA-4000-series	O
hard	B-Device
disk	I-Device
,	O
and	O
an	O
8-inch	B-Device
floppy	I-Device
disk	O
drive	O
.	O
</s>
<s>
The	O
internal	O
layout	O
of	O
the	O
PERQ	B-Device
1	O
was	O
dominated	O
by	O
the	O
vertically	O
mounted	O
hard	B-Device
disk	I-Device
drive	I-Device
.	O
</s>
<s>
A	O
basic	O
PERQ	B-Device
1	O
system	O
comprised	O
a	O
CPU	B-General_Concept
board	O
,	O
a	O
memory	O
board	O
(	O
incorporating	O
the	O
framebuffer	B-Algorithm
and	O
monitor	O
interface	O
)	O
and	O
an	O
I/O	B-General_Concept
board	O
(	O
IOB	O
,	O
also	O
called	O
CIO	O
)	O
.	O
</s>
<s>
The	O
IOB	O
included	O
a	O
Zilog	B-General_Concept
Z80	I-General_Concept
microprocessor	B-Architecture
,	O
an	O
IEEE-488	O
interface	O
,	O
an	O
RS-232	O
serial	B-Protocol
port	I-Protocol
,	O
hard	O
and	O
floppy	B-Device
disk	I-Device
interfaces	O
and	O
speech	B-Application
synthesis	I-Application
hardware	O
.	O
</s>
<s>
PERQ	B-Device
1s	O
also	O
had	O
a	O
spare	O
Optional	O
I/O	B-General_Concept
(	O
OIO	O
)	O
board	O
slot	O
for	O
additional	O
interfaces	O
such	O
as	O
Ethernet	O
.	O
</s>
<s>
A	O
graphics	B-Device
tablet	I-Device
was	O
standard	O
.	O
</s>
<s>
Most	O
PERQ	B-Device
1s	O
were	O
supplied	O
with	O
an	O
8½	O
×	O
11-inch	O
,	O
768×1024	O
pixel	O
portrait	O
orientation	O
white	O
phosphor	O
monochrome	O
monitor	O
.	O
</s>
<s>
The	O
PERQ	B-Device
2	O
(	O
codenamed	O
Kristmas	O
during	O
development	O
)	O
was	O
announced	O
in	O
1983	O
.	O
</s>
<s>
The	O
PERQ	B-Device
2	O
could	O
be	O
distinguished	O
from	O
the	O
PERQ	B-Device
1	O
by	O
its	O
wider	O
,	O
ICL-designed	O
cabinet	O
,	O
with	O
a	O
lighter-coloured	O
fascia	O
,	O
vertical	O
floppy	B-Device
disk	I-Device
drive	I-Device
and	O
three-digit	O
diagnostic	O
display	O
.	O
</s>
<s>
The	O
PERQ	B-Device
2	O
used	O
the	O
same	O
16k	O
WCS	O
CPU	B-General_Concept
as	O
the	O
PERQ	B-Device
1A	O
and	O
had	O
a	O
3-button	O
mouse	B-Device
in	O
place	O
of	O
the	O
graphics	B-Device
tablet	I-Device
.	O
</s>
<s>
It	O
was	O
configured	O
with	O
a	O
quieter	O
8-inch	O
35	O
MB	O
Micropolis	O
Corporation	O
1201	O
hard	B-Device
disk	I-Device
,	O
1	O
or	O
2	O
MB	O
of	O
RAM	B-Architecture
and	O
had	O
the	O
option	O
of	O
the	O
PERQ	B-Device
1	O
's	O
portrait	O
monitor	O
or	O
a	O
19-inch	O
,	O
1280×1024	O
landscape	O
orientation	O
monitor	O
.	O
</s>
<s>
Due	O
to	O
manufacturing	O
problems	O
with	O
the	O
original	O
3RCC	B-Device
PERQ	I-Device
2	O
(	O
also	O
known	O
as	O
the	O
K1	O
)	O
,	O
ICL	O
revised	O
the	O
hardware	O
design	O
,	O
resulting	O
in	O
the	O
PERQ	B-Device
2	O
T1	O
(	O
or	O
ICL	O
8222	O
)	O
.	O
</s>
<s>
The	O
later	O
PERQ	B-Device
2	O
T2	O
(	O
ICL	O
8223	O
)	O
and	O
PERQ	B-Device
2	O
T4	O
models	O
replaced	O
the	O
8-inch	O
hard	B-Device
disk	I-Device
with	O
a	O
5¼-inch	O
hard	B-Device
disk	I-Device
,	O
which	O
also	O
allowed	O
for	O
a	O
second	O
disk	O
to	O
be	O
installed	O
internally	O
.	O
</s>
<s>
The	O
T4	O
model	O
(	O
of	O
which	O
only	O
around	O
10	O
are	O
thought	O
to	O
have	O
been	O
produced	O
)	O
had	O
an	O
extended	O
24-bit	O
CPU	B-General_Concept
and	O
backplane	B-Architecture
bus	O
,	O
allowing	O
the	O
use	O
of	O
a	O
4MB	O
RAM	B-Architecture
board	O
.	O
</s>
<s>
The	O
PERQ	B-Device
2	O
retained	O
the	O
PERQ	B-Device
1	O
's	O
OIO	O
slot	O
,	O
but	O
replaced	O
the	O
IOB	O
with	O
either	O
an	O
EIO	O
(	O
Ethernet	O
I/O	B-General_Concept
)	O
or	O
NIO	O
(	O
Non-Ethernet	O
I/O	B-General_Concept
)	O
boards	O
.	O
</s>
<s>
These	O
were	O
similar	O
to	O
the	O
IOB	O
,	O
with	O
the	O
addition	O
of	O
a	O
non-volatile	B-General_Concept
real-time	O
clock	O
,	O
a	O
second	O
RS-232	O
port	O
,	O
and	O
(	O
on	O
the	O
EIO	O
board	O
)	O
an	O
Ethernet	O
interface	O
.	O
</s>
<s>
The	O
PERQ	B-Device
3A	O
(	O
otherwise	O
known	O
as	O
the	O
ICL	O
3300	O
Advanced	O
Graphics	O
Workstation	B-Device
)	O
was	O
developed	O
by	O
ICL	O
as	O
a	O
replacement	O
for	O
the	O
PERQ	B-Device
2	O
.	O
</s>
<s>
The	O
PERQ	B-Device
3A	O
had	O
an	O
all-new	O
hardware	O
architecture	O
based	O
around	O
a	O
12.5MHz	O
Motorola	B-Device
68020	I-Device
microprocessor	B-Architecture
,	O
68881	B-General_Concept
floating-point	B-General_Concept
unit	I-General_Concept
and	O
68450	O
Direct	O
Memory	O
Access	O
Controller	O
,	O
plus	O
two	O
AMD	B-General_Concept
29116A	I-General_Concept
32-bit	O
bit	B-General_Concept
slice	I-General_Concept
processors	I-General_Concept
which	O
acted	O
as	O
graphics	O
co-processors	O
.	O
</s>
<s>
It	O
also	O
had	O
up	O
to	O
2	O
MB	O
of	O
RAM	B-Architecture
,	O
a	O
SCSI	B-Architecture
hard	B-Device
disk	I-Device
and	O
was	O
housed	O
in	O
a	O
desktop	O
"	O
mini-tower	O
"	O
-style	O
enclosure	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
was	O
a	O
port	O
of	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
Release	O
2	O
called	O
PNX	O
300	O
.	O
</s>
<s>
Prototype	O
units	O
were	O
produced	O
in	O
1985	O
,	O
but	O
the	O
project	O
was	O
cancelled	O
before	O
full	O
production	O
commenced	O
(	O
the	O
project	O
had	O
run	O
late	O
and	O
ICL	O
decided	O
it	O
was	O
a	O
solution	O
provider	O
-	O
it	O
would	O
sell	O
Sun	O
workstations	B-Device
as	O
part	O
of	O
the	O
solution	O
)	O
.	O
</s>
<s>
Another	O
workstation	B-Device
design	O
under	O
development	O
at	O
the	O
time	O
of	O
the	O
company	O
's	O
demise	O
,	O
the	O
PERQ	B-Device
3B	O
was	O
a	O
colour	O
model	O
(	O
sometimes	O
referred	O
to	O
as	O
the	O
PERQ	B-Device
5	O
)	O
was	O
taken	O
over	O
by	O
Crosfield	O
Electronics	O
for	O
its	O
Crosfield	O
Studio	O
9500	O
page	O
layout	O
workstation	B-Device
.	O
</s>
<s>
The	O
workstation	B-Device
was	O
also	O
known	O
internally	O
as	O
Python	O
,	O
was	O
developed	O
in	O
1986	O
jointly	O
by	O
MegaScan	O
and	O
Conner	O
Scelza	O
Associates	O
(	O
both	O
in	O
Gibsonia	O
,	O
Pittsburgh	O
)	O
and	O
the	O
Crosfield	O
team	O
(	O
in	O
Hemel	O
Hempstead	O
,	O
England	O
)	O
.	O
</s>
<s>
MegaScan	O
,	O
led	O
by	O
Brian	O
Rosen	O
,	O
developed	O
the	O
workstation	B-Device
electronics	O
and	O
Conner	O
Scelza	O
Associates	O
(	O
led	O
by	O
Jerry	O
Conner	O
and	O
Don	O
Scelza	O
)	O
ported	O
UNIX	B-Application
and	O
wrote	O
all	O
the	O
other	O
supporting	O
software	O
.	O
</s>
<s>
The	O
Crosfield	O
team	O
in	O
Hemel	O
Hempstead	O
developed	O
an	O
early	O
RAID	B-Architecture
solution	O
that	O
supported	O
up	O
to	O
8	O
SCSI	B-Architecture
controllers	O
operating	O
in	O
parallel	O
with	O
data	O
streaming	O
from	O
5¼-inch	O
full-height	B-Device
drives	I-Device
and	O
a	O
fast	O
fibre-optic	B-Architecture
network	I-Architecture
known	O
as	O
GALAN	O
.	O
</s>
<s>
Various	O
optional	O
OIO	O
boards	O
were	O
produced	O
for	O
the	O
PERQ	B-Device
1	O
and	O
2	O
:	O
3RCC	O
OIO	O
boards	O
provided	O
a	O
16-bit	O
parallel	O
PERQlink	O
interface	O
(	O
intended	O
for	O
downloading	O
microcode	B-Device
from	O
another	O
PERQ	B-Device
at	O
boot	O
time	O
)	O
plus	O
Ethernet	O
and/or	O
a	O
Canon	O
CX	O
laser	O
printer	O
controller	O
.	O
</s>
<s>
Thus	O
,	O
a	O
PERQ	B-Device
2	O
could	O
be	O
configured	O
with	O
two	O
Ethernet	O
ports	O
(	O
EIO	O
plus	O
OIO	O
)	O
.	O
</s>
<s>
Other	O
third-party	O
OIO	O
boards	O
were	O
produced	O
to	O
interface	O
to	O
other	O
devices	O
,	O
such	O
as	O
QIC-02	O
tape	O
drives	O
or	O
video	O
cameras	O
.	O
</s>
<s>
The	O
PERQ	B-Device
's	O
original	O
p-Code-like	O
instruction	O
set	O
(	O
called	O
Q-Code	O
)	O
was	O
optimized	O
for	O
Pascal	B-Application
(	O
specifically	O
,	O
an	O
extended	O
PERQ	B-Device
Pascal	B-Application
)	O
.	O
</s>
<s>
This	O
gave	O
rise	O
to	O
the	O
alternative	O
definition	O
of	O
the	O
PERQ	B-Device
name	O
:	O
Pascal	B-Application
Evaluation	O
Real	O
Quick	O
.	O
</s>
<s>
In	O
fact	O
it	O
was	O
generally	O
more	O
efficient	O
to	O
use	O
Pascal	B-Application
than	O
to	O
attempt	O
to	O
create	O
"	O
assembly	B-Language
language	I-Language
"	O
programs	O
directly	O
with	O
Q-Code	O
.	O
</s>
<s>
A	O
variety	O
of	O
operating	B-General_Concept
systems	I-General_Concept
were	O
developed	O
for	O
the	O
PERQ	B-Device
.	O
</s>
<s>
POS	O
(	O
PERQ	B-Device
Operating	B-General_Concept
System	I-General_Concept
)	O
The	O
initial	O
single-task	O
operating	B-General_Concept
system	I-General_Concept
for	O
PERQ	B-Device
workstations	I-Device
,	O
developed	O
by	O
3RCC	O
.	O
</s>
<s>
POS	O
and	O
its	O
utilities	O
were	O
written	O
in	O
PERQ	B-Device
Pascal	B-Application
.	O
</s>
<s>
MPOS	O
(	O
Multitasking	B-Operating_System
POS	O
)	O
A	O
multitasking	B-Operating_System
version	O
of	O
POS	O
,	O
not	O
officially	O
released	O
by	O
3RCC	O
.	O
</s>
<s>
Accent	B-Operating_System
A	O
multitasking	B-Operating_System
research	O
operating	B-General_Concept
system	I-General_Concept
developed	O
at	O
CMU	O
,	O
with	O
a	O
window	B-Application
manager	I-Application
called	O
Sapphire	O
.	O
</s>
<s>
Accent	B-Operating_System
was	O
a	O
predecessor	O
of	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
which	O
many	O
later	O
operating	B-General_Concept
systems	I-General_Concept
would	O
use	O
.	O
</s>
<s>
A	O
UNIX	O
System	O
V-compatible	O
environment	O
running	O
under	O
Accent	B-Operating_System
in	O
a	O
Sapphire	O
window	O
,	O
called	O
QNIX	O
,	O
was	O
developed	O
by	O
Spider	O
Systems	O
.	O
</s>
<s>
PNX	O
(	O
)	O
A	O
port	O
of	O
Unix	B-Application
for	O
the	O
PERQ	B-Device
,	O
based	O
on	O
Seventh	B-Operating_System
Edition	I-Operating_System
Unix	I-Operating_System
and	O
UNIX	B-Operating_System
System	I-Operating_System
III	I-Operating_System
.	O
</s>
<s>
PNX	O
used	O
its	O
own	O
microcode	B-Device
,	O
more	O
appropriate	O
for	O
the	O
C	B-Language
programming	I-Language
language	I-Language
,	O
called	O
C-Code	O
.	O
</s>
<s>
FLEX	B-Device
Developed	O
by	O
the	O
Royal	O
Signals	O
and	O
Radar	O
Establishment	O
,	O
FLEX	B-Device
was	O
implemented	O
in	O
microcode	B-Device
and	O
similar	O
to	O
other	O
early	O
workstation	B-Device
systems	O
such	O
as	O
Lisp	B-Operating_System
machines	I-Operating_System
,	O
UCSD	B-Language
Pascal	I-Language
or	O
Modula-2	B-Language
,	O
except	O
that	O
the	O
language	O
of	O
choice	O
was	O
ALGOL	B-Language
68	I-Language
.	O
</s>
<s>
By	O
1987	O
,	O
maintenance	O
of	O
the	O
PERQ	B-Device
compiler	O
suite	O
had	O
been	O
taken	O
over	O
by	O
a	O
commercial	O
spin-off	O
group	O
of	O
ex-ERCC	O
employees	O
,	O
Edinburgh	O
Portable	O
Compilers	O
Ltd	O
(	O
EPCL	O
)	O
.	O
</s>
<s>
The	O
PERQ	B-Device
was	O
a	O
popular	O
early	O
graphical	O
workstation	B-Device
;	O
therefore	O
,	O
it	O
helped	O
spawn	O
many	O
early	O
third-party	O
applications	O
that	O
took	O
advantage	O
of	O
the	O
graphical	B-Application
user	I-Application
interface	I-Application
and	O
bitmapped	B-Algorithm
graphics	I-Algorithm
.	O
</s>
<s>
The	O
PERQ	B-Device
also	O
served	O
as	O
a	O
dedicated	O
platform	O
for	O
several	O
pioneering	O
hypertext	O
programs	O
,	O
such	O
as	O
ZOG	B-Application
,	O
KMS	O
,	O
and	O
Guide	O
.	O
</s>
<s>
DP	O
(	O
"	O
Drawing	O
Program	O
"	O
)	O
,	O
a	O
CAD	B-Application
system	O
used	O
for	O
creating	O
circuit	B-Application
diagrams	I-Application
on	O
the	O
PERQ	B-Device
,	O
was	O
written	O
by	O
Dario	O
Giuse	O
at	O
CMU	O
.	O
</s>
