<s>
The	O
system	O
used	O
the	O
new	O
OC71	O
transistors	B-Application
from	O
Mullard	O
,	O
originally	O
designed	O
for	O
use	O
in	O
hearing	O
aids	O
.	O
</s>
<s>
Among	O
these	O
was	O
the	O
introduction	O
of	O
interrupts	B-Application
to	O
better	O
handle	O
timing	O
of	O
various	O
events	O
.	O
</s>
<s>
These	O
sorts	O
of	O
tasks	O
were	O
now	O
controlled	O
by	O
interrupts	B-Application
,	O
so	O
the	O
device	O
could	O
indicate	O
when	O
its	O
data	O
was	O
ready	O
to	O
be	O
processed	O
.	O
</s>
<s>
The	O
system	O
added	O
core	B-General_Concept
memory	I-General_Concept
for	O
temporary	O
storage	O
,	O
replacing	O
the	O
flip-flops	B-General_Concept
from	O
the	O
earlier	O
system	O
,	O
and	O
a	O
plugboard	O
for	O
programming	O
.	O
</s>
<s>
The	O
Argus	O
circuitry	O
was	O
based	O
on	O
germanium	O
transistors	B-Application
with	O
0	O
and	O
-6	O
volts	O
representing	O
binary	O
1	O
and	O
0	O
,	O
respectively	O
.	O
</s>
<s>
Additions	O
in	O
the	O
ALU	B-General_Concept
took	O
12	O
µs	O
,	O
but	O
adding	O
in	O
the	O
memory	O
access	O
time	O
meant	O
simple	O
instructions	O
took	O
about	O
20	O
µs	O
.	O
</s>
<s>
Data	O
memory	O
was	O
supplied	O
in	O
a	O
12-bit	O
,	O
4096	O
word	O
,	O
core	B-General_Concept
memory	I-General_Concept
store	O
,	O
while	O
up	O
to	O
64	O
instruction	O
words	O
were	O
stored	O
in	O
a	O
separate	O
plugboard	O
tray	O
then	O
8	O
trays	O
to	O
a	O
box	O
and	O
4	O
boxes	O
in	O
a	O
rack	O
giving	O
2048	O
lines	O
of	O
program	O
,	O
using	O
ferrite	O
pegs	O
dropped	O
into	O
holes	O
to	O
create	O
a	O
"	O
1	O
"	O
.	O
</s>
<s>
He	O
suggested	O
placing	O
the	O
computers	O
at	O
the	O
Orange	B-Algorithm
Yeoman	I-Algorithm
radar	O
sites	O
as	O
calculation	O
centers	O
that	O
would	O
feed	O
this	O
information	O
to	O
the	O
missile	O
batteries	O
.	O
</s>
<s>
The	O
original	O
design	O
was	O
followed	O
in	O
1963	O
by	O
the	O
single-ALU	O
Argus	O
100	O
,	O
which	O
cost	O
around	O
£	O
20,000	O
(	O
equivalent	O
to	O
approximately	O
£	O
430,000	O
)	O
.	O
</s>
<s>
The	O
single	O
ALU	B-General_Concept
and	O
other	O
changes	O
resulted	O
in	O
a	O
basic	O
operation	O
time	O
of	O
72	O
μs	O
.	O
</s>
<s>
This	O
was	O
a	O
much	O
faster	O
machine	O
featuring	O
a	O
fully	O
parallel-architecture	O
arithmetic	B-General_Concept
logic	I-General_Concept
unit	I-General_Concept
,	O
as	O
opposed	O
to	O
the	O
earlier	O
and	O
much	O
slower	O
serial	O
units	O
.	O
</s>
<s>
A	O
variant	O
of	O
the	O
300	O
was	O
the	O
Argus	O
350	O
,	O
which	O
allowed	O
external	O
access	O
to	O
its	O
core	O
to	O
allow	O
direct	B-General_Concept
memory	I-General_Concept
access	I-General_Concept
.	O
</s>
<s>
This	O
improved	O
performance	O
of	O
input/output	B-General_Concept
,	O
avoiding	O
having	O
to	O
move	O
data	O
via	O
code	O
running	O
on	O
the	O
processor	O
.	O
</s>
<s>
Previous	O
machines	O
used	O
germanium	O
transistors	B-Application
to	O
form	O
the	O
logic	O
gates	O
.	O
</s>
<s>
The	O
Argus	O
400	O
used	O
silicon	O
transistors	B-Application
in	O
a	O
NOR-logic	O
designed	O
by	O
Ferranti	O
Wythenshawe	O
called	O
MicroNOR	O
II''	O
,	O
with	O
more	O
"	O
conventional	O
"	O
logic	O
where	O
0	O
and	O
+	O
4.5	O
represented	O
binary	O
1	O
and	O
0	O
,	O
respectively	O
.	O
</s>
<s>
The	O
Argus	O
400	O
was	O
repackaged	O
to	O
be	O
the	O
same	O
as	O
the	O
Argus	O
500	O
and	O
the	O
two	O
machines	O
were	O
plug	B-Device
compatible	I-Device
.	O
</s>
<s>
The	O
500	O
added	O
new	O
instructions	O
that	O
used	O
three-bits	O
of	O
the	O
accumulator	B-General_Concept
for	O
offset	O
indexing	O
as	O
well	O
.	O
</s>
<s>
Both	O
used	O
core	B-General_Concept
memory	I-General_Concept
which	O
was	O
available	O
in	O
two	O
cycle	O
times	O
.	O
</s>
<s>
The	O
difference	O
between	O
the	O
400	O
and	O
500	O
was	O
similar	O
to	O
the	O
split	O
between	O
the	O
100	O
and	O
300	O
,	O
in	O
that	O
the	O
500	O
had	O
a	O
parallel	O
ALU	B-General_Concept
and	O
the	O
400	O
was	O
serial	O
.	O
</s>
<s>
A	O
CORAL	B-Language
66	I-Language
high-level	O
programming	O
language	O
compiler	O
for	O
the	O
Argus	O
500	O
was	O
developed	O
by	O
the	O
Royal	O
Signals	O
and	O
Radar	O
Establishment	O
under	O
contract	O
to	O
Ferranti	O
for	O
use	O
in	O
industrial	O
control	O
and	O
automation	O
projects	O
.	O
</s>
<s>
This	O
removed	O
the	O
multiply	O
and	O
divide	O
functions	O
as	O
these	O
used	O
a	O
significant	O
number	O
of	O
expensive	O
JK	O
flip-flops	B-General_Concept
and	O
it	O
was	O
cost	O
effective	O
at	O
the	O
time	O
to	O
save	O
these	O
24	O
and	O
a	O
few	O
other	O
components	O
.	O
</s>
<s>
It	O
possessed	O
a	O
basic	O
core	B-General_Concept
memory	I-General_Concept
of	O
1,024	O
words	O
,	O
expandable	O
in	O
blocks	O
of	O
the	O
same	O
size	O
up	O
to	O
a	O
maximum	O
of	O
8,192	O
words	O
.	O
</s>
<s>
The	O
Argus	O
700F	O
used	O
500	O
ns	O
cycle	O
time	O
MOS	B-Architecture
memory	I-Architecture
of	O
up	O
to	O
64k	O
16-bit	O
words	O
.	O
</s>
<s>
The	O
Argus	O
700G	O
supported	O
a	O
virtual	B-General_Concept
address	I-General_Concept
space	I-General_Concept
with	O
up	O
to	O
256k	O
words	O
of	O
memory	O
.	O
</s>
<s>
The	O
Argus	O
700S	O
had	O
the	O
option	O
of	O
faster	O
150	O
ns	O
bipolar	B-Architecture
memory	I-Architecture
with	O
independent	O
access	O
for	O
input-output	B-General_Concept
processors	O
.	O
</s>
<s>
The	O
Argus	O
700	O
also	O
played	O
an	O
important	O
historical	O
role	O
in	O
the	O
development	O
of	O
packet	B-Protocol
switching	I-Protocol
networks	O
in	O
the	O
UK	O
.	O
</s>
<s>
These	O
machines	O
were	O
used	O
by	O
Ferranti	O
during	O
early	O
experiments	O
at	O
the	O
General	O
Post	O
Office	O
as	O
the	O
basis	O
for	O
early	O
routers	B-Protocol
.	O
</s>
<s>
In	O
this	O
respect	O
they	O
are	O
similar	O
to	O
the	O
Interface	B-Protocol
Message	I-Protocol
Processors	I-Protocol
built	O
in	O
the	O
US	O
to	O
serve	O
a	O
similar	O
role	O
during	O
the	O
development	O
of	O
the	O
Internet	O
.	O
</s>
<s>
When	O
first	O
installed	O
it	O
was	O
probably	O
the	O
most	O
sophisticated	O
and	O
complex	O
computerised	O
control	O
system	O
for	O
a	O
nuclear	O
power	O
station	O
worldwide	O
;	O
the	O
system	O
was	O
implemented	O
using	O
the	O
CORAL	B-Language
high-level	I-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
The	O
M700	O
series	O
of	O
computers	O
was	O
based	O
on	O
the	O
architecture	O
and	O
instruction	O
set	O
of	O
the	O
Ferranti	B-Device
Argus	I-Device
700	O
computer	O
series	O
.	O
</s>
