<s>
The	O
DRTE	B-Device
Computer	I-Device
was	O
a	O
transistorized	B-Device
computer	I-Device
built	O
at	O
the	O
Defence	O
Research	O
Telecommunications	O
Establishment	O
(	O
DRTE	O
)	O
,	O
part	O
of	O
the	O
Canadian	O
Defence	O
Research	O
Board	O
.	O
</s>
<s>
Although	O
the	O
performance	O
was	O
quite	O
good	O
,	O
equal	O
to	O
that	O
of	O
contemporary	O
machines	O
like	O
the	O
PDP-1	B-Device
,	O
no	O
commercial	O
vendors	O
ever	O
took	O
up	O
the	O
design	O
,	O
and	O
the	O
only	O
potential	O
sale	O
to	O
the	O
Canadian	O
Navy	O
's	O
Pacific	O
Naval	O
Laboratories	O
,	O
fell	O
through	O
.	O
</s>
<s>
The	O
key	O
development	O
that	O
led	O
to	O
the	O
eventual	O
construction	O
of	O
the	O
computer	O
was	O
Moody	O
's	O
invention	O
of	O
a	O
new	O
type	O
of	O
flip-flop	B-General_Concept
circuit	O
,	O
a	O
key	O
component	O
of	O
all	O
computer	O
systems	O
.	O
</s>
<s>
Most	O
machines	O
of	O
the	O
era	O
used	O
Eccles-Jordan	O
flip-flops	B-General_Concept
;	O
this	O
was	O
originally	O
a	O
tube-based	O
concept	O
that	O
was	O
being	O
used	O
by	O
replacing	O
the	O
tubes	O
with	O
transistors	O
.	O
</s>
<s>
One	O
downside	O
,	O
only	O
realized	O
later	O
,	O
is	O
that	O
the	O
current	O
draw	O
of	O
Moody	O
's	O
flip-flop	B-General_Concept
was	O
not	O
balanced	O
,	O
so	O
storing	O
different	O
numbers	O
in	O
them	O
could	O
lead	O
to	O
dramatically	O
different	O
current	O
needs	O
on	O
the	O
power	O
supply	O
.	O
</s>
<s>
But	O
as	O
development	O
continued	O
,	O
many	O
of	O
the	O
engineers	O
involved	O
became	O
more	O
interested	O
in	O
computer	B-General_Concept
design	I-General_Concept
than	O
electronics	O
.	O
</s>
<s>
Starting	O
about	O
1955	O
,	O
David	O
Florida	O
drove	O
the	O
development	O
of	O
a	O
computer	O
using	O
Moody	O
's	O
flip-flop	B-General_Concept
design	O
.	O
</s>
<s>
He	O
examined	O
existing	O
computer	B-General_Concept
designs	I-General_Concept
and	O
concluded	O
that	O
the	O
main	O
limitation	O
in	O
computer	O
complexity	O
was	O
due	O
largely	O
to	O
the	O
burnout	O
rate	O
of	O
the	O
tubes	O
;	O
a	O
more	O
powerful	O
design	O
required	O
more	O
tubes	O
,	O
which	O
meant	O
more	O
frequent	O
burnouts	O
.	O
</s>
<s>
Although	O
a	O
number	O
of	O
truly	O
massive	O
machines	O
had	O
been	O
built	O
,	O
like	O
SAGE	B-Device
,	O
most	O
machines	O
were	O
much	O
smaller	O
in	O
order	O
to	O
improve	O
uptime	O
.	O
</s>
<s>
In	O
particular	O
,	O
the	O
design	O
ultimately	O
included	O
a	O
number	O
of	O
subsystems	O
for	O
input/output	B-General_Concept
,	O
a	O
hardware	O
binary/decimal	O
converter	O
,	O
</s>
<s>
floating-point	B-Algorithm
hardware	O
including	O
a	O
square	O
root	O
function	O
,	O
a	O
number	O
of	O
loop	O
instructions	O
and	O
index	B-General_Concept
registers	I-General_Concept
to	O
support	O
them	O
,	O
and	O
used	O
a	O
complex	O
three-address	O
instruction	O
format	O
.	O
</s>
<s>
Florida	O
had	O
previously	O
worked	O
with	O
the	O
team	O
building	O
the	O
Manchester	B-Device
Mark	I-Device
1	I-Device
,	O
and	O
following	O
their	O
lead	O
he	O
designed	O
the	O
DRTE	O
machine	O
with	O
40-bit	O
words	O
.	O
</s>
<s>
Integers	O
used	O
39	O
bits	O
and	O
one	O
bit	O
for	O
a	O
sign	O
,	O
while	O
floating	B-Algorithm
point	I-Algorithm
numbers	I-Algorithm
had	O
an	O
8-bit	O
exponent	O
with	O
one	O
bit	O
for	O
the	O
sign	O
and	O
a	O
32-bit	O
mantissa	O
with	O
one	O
bit	O
for	O
the	O
sign	O
.	O
</s>
<s>
A	O
floating	B-Algorithm
point	I-Algorithm
add	O
took	O
between	O
50	O
and	O
365	O
microseconds	O
( μS	O
)	O
.	O
</s>
<s>
The	O
longest	O
instructions	O
,	O
divide	O
or	O
square	O
root	O
,	O
took	O
5.3	O
milliseconds	O
(	O
ms	O
)	O
for	O
floating	B-Algorithm
point	I-Algorithm
.	O
</s>
<s>
The	O
computer	O
used	O
core	B-General_Concept
memory	I-General_Concept
for	O
all	O
storage	O
,	O
lacking	O
"	O
secondary	O
"	O
systems	O
such	O
as	O
a	O
memory	B-General_Concept
drum	I-General_Concept
.	O
</s>
<s>
I/O	B-General_Concept
device	I-General_Concept
on	O
the	O
DRTE	O
design	O
were	O
extremely	O
limited	O
,	O
consisting	O
of	O
a	O
Flexowriter	B-Application
for	O
output	O
,	O
and	O
a	O
paper	O
tape	O
reader	O
at	O
about	O
600	O
CPS	O
for	O
input	O
.	O
</s>
<s>
In	O
particular	O
,	O
the	O
system	O
added	O
a	O
hardware	O
binary-to-decimal/decimal	O
-to-binary	O
converter	O
that	O
was	O
implemented	O
inline	O
with	O
the	O
I/O	B-General_Concept
systems	O
.	O
</s>
<s>
The	O
system	O
also	O
offered	O
a	O
crude	O
sort	O
of	O
assembler	B-Language
language	I-Language
support	O
.	O
</s>
<s>
For	O
instance	O
,	O
the	O
letters	O
"	O
AA	O
"	O
would	O
add	O
two	O
floating	B-Algorithm
point	I-Algorithm
numbers	I-Algorithm
,	O
the	O
numbers	O
being	O
stored	O
in	O
the	O
two	O
decimal	O
addresses	O
following	O
.	O
</s>
<s>
If	O
one	O
assumed	O
that	O
all	O
the	O
data	O
being	O
read	O
and	O
written	O
was	O
a	O
decimal	O
representation	O
of	O
binary	O
data	O
the	O
system	O
made	O
perfect	O
sense	O
,	O
but	O
if	O
the	O
data	O
was	O
in	O
some	O
other	O
form	O
,	O
more	O
complex	O
assembler	B-Language
language	I-Language
character	O
codes	O
for	O
instance	O
,	O
it	O
ended	O
up	O
simply	O
adding	O
complexity	O
that	O
then	O
had	O
to	O
be	O
turned	O
off	O
.	O
</s>
<s>
The	O
system	O
was	O
eventually	O
removed	O
when	O
assembler	B-Language
programming	I-Language
became	O
common	O
.	O
</s>
<s>
This	O
improved	O
speeds	O
by	O
about	O
ten	O
times	O
,	O
for	O
instance	O
,	O
a	O
floating-point	B-Algorithm
add	O
improved	O
from	O
300	O
μs	O
to	O
only	O
40	O
,	O
multiplication	O
from	O
2200	O
to	O
180	O
μs	O
,	O
and	O
a	O
square	O
root	O
from	O
5300	O
to	O
510	O
microseconds	O
.	O
</s>
<s>
With	O
the	O
new	O
math	O
unit	O
the	O
machine	O
was	O
faster	O
than	O
the	O
average	O
contemporary	O
system	O
,	O
although	O
slower	O
than	O
"	O
high	O
end	O
"	O
machines	O
like	O
the	O
IBM	B-Device
7090	I-Device
by	O
about	O
two	O
to	O
five	O
times	O
.	O
</s>
<s>
These	O
included	O
tic-tac-toe	O
and	O
hangman	O
,	O
as	O
well	O
as	O
a	O
simple	O
music	O
generator	O
that	O
could	O
play	O
the	O
Colonel	O
Bogey	O
March	O
by	O
attaching	O
a	O
speaker	O
to	O
a	O
particular	O
flip-flop	B-General_Concept
.	O
</s>
<s>
In	O
the	O
late	O
1950s	O
the	O
US	O
was	O
in	O
the	O
midst	O
of	O
rolling	O
out	O
the	O
SAGE	B-Device
system	I-Device
,	O
and	O
became	O
interested	O
in	O
the	O
effects	O
of	O
aurora	O
borealis	O
on	O
radar	B-Application
operation	O
.	O
</s>
<s>
An	O
agreement	O
was	O
eventually	O
signed	O
between	O
the	O
DRB	O
and	O
US	O
Air	O
Force	O
,	O
with	O
the	O
Air	O
Force	O
providing	O
two	O
million	O
dollars	O
to	O
build	O
a	O
radar	B-Application
research	O
center	O
modelled	O
on	O
MIT	O
's	O
Lincoln	O
Laboratory	O
,	O
which	O
had	O
provided	O
much	O
of	O
the	O
US	O
technical	O
lead	O
in	O
radar	B-Application
systems	I-Application
.	O
</s>
<s>
Such	O
a	O
location	O
would	O
allow	O
the	O
radars	B-Application
to	O
directly	O
measure	O
the	O
effects	O
of	O
aurora	O
on	O
radar	B-Application
by	O
tracking	O
the	O
rocket	O
launches	O
.	O
</s>
<s>
The	O
new	O
site	O
was	O
opened	O
in	O
June	O
1959	O
,	O
known	O
as	O
the	O
Prince	O
Albert	O
Radar	B-Application
Laboratory	O
,	O
or	O
PARL	O
.	O
</s>
<s>
DAR	O
was	O
a	O
fairly	O
high-priority	O
project	O
,	O
and	O
some	O
of	O
the	O
manpower	O
originally	O
working	O
on	O
the	O
DRTE	B-Device
computer	I-Device
were	O
put	O
on	O
DAR	O
instead	O
.	O
</s>
<s>
The	O
machine	O
itself	O
consisted	O
of	O
a	O
non-programmable	O
computer	O
that	O
read	O
the	O
data	O
into	O
40,000	O
bits	O
of	O
core	B-General_Concept
memory	I-General_Concept
,	O
tagged	O
it	O
with	O
timecode	O
and	O
other	O
information	O
,	O
and	O
then	O
wrote	O
it	O
to	O
magnetic	O
tape	O
.	O
</s>
<s>
While	O
Alouette	O
was	O
being	O
designed	O
,	O
a	O
major	O
question	O
about	O
the	O
lifetime	O
of	O
the	O
solar	O
cells	O
powering	O
the	O
system	O
came	O
to	O
be	O
solved	O
on	O
the	O
DRTE	B-Device
computer	I-Device
.	O
</s>
