<s>
Concurrent	B-Language
Euclid	I-Language
(	O
ConEuc	O
)	O
is	O
a	O
concurrent	O
descendant	O
of	O
the	O
Euclid	B-Language
programming	I-Language
language	I-Language
designed	O
by	O
James	O
Cordy	O
and	O
Ric	O
Holt	O
,	O
then	O
at	O
the	O
University	O
of	O
Toronto	O
,	O
in	O
1980	O
.	O
</s>
<s>
ConEuc	O
was	O
designed	O
for	O
concurrent	O
,	O
high	O
performance	O
,	O
highly	O
reliable	O
system	B-Application
software	I-Application
,	O
such	O
as	O
operating	B-General_Concept
systems	I-General_Concept
,	O
compilers	B-Language
and	O
embedded	B-Architecture
microprocessor	I-Architecture
systems	O
.	O
</s>
<s>
The	O
TUNIS	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
a	O
Unix	B-Application
variant	O
,	O
was	O
implemented	O
entirely	O
in	O
Concurrent	B-Language
Euclid	I-Language
.	O
</s>
<s>
ConEuc	O
extends	O
a	O
core	O
subset	O
of	O
Euclid	B-Language
with	O
processes	B-Operating_System
and	O
monitors	O
(	O
as	O
specified	O
by	O
C.A.R.	O
</s>
<s>
Hoare	O
)	O
as	O
well	O
as	O
language	O
constructs	O
needed	O
for	O
systems	O
programming	O
including	O
separate	O
compilation	B-Language
,	O
variables	O
at	O
absolute	O
addresses	O
,	O
type	O
converters	O
,	O
long	O
integers	O
and	O
other	O
features	O
.	O
</s>
<s>
ConEuc	O
was	O
implemented	O
by	O
a	O
small	O
(	O
50k	O
bytes	O
)	O
,	O
fast	O
,	O
portable	O
compiler	B-Language
that	O
was	O
self-compiling	O
and	O
had	O
replaceable	O
code	O
generators	O
.	O
</s>
<s>
High	O
quality	O
code	O
generators	O
for	O
several	O
computers	O
,	O
including	O
the	O
PDP-11	B-Device
,	O
VAX-11	O
,	O
Motorola	B-Device
68000	I-Device
and	O
Motorola	B-Device
6809	I-Device
were	O
developed	O
that	O
produced	O
code	O
comparable	O
to	O
the	O
best	O
C	B-Language
compilers	B-Language
.	O
</s>
<s>
Concurrent	B-Language
Euclid	I-Language
programs	O
that	O
used	O
concurrency	O
could	O
be	O
run	O
on	O
a	O
bare	O
machine	O
(	O
supported	O
by	O
a	O
small	O
assembly	O
language	O
kernel	O
)	O
,	O
or	O
in	O
simulated	O
mode	O
as	O
an	O
ordinary	O
process	O
running	O
under	O
an	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
Turing	B-Language
programming	I-Language
language	I-Language
is	O
a	O
direct	O
descendant	O
of	O
Concurrent	B-Language
Euclid	I-Language
and	O
its	O
Turing	B-Language
Plus	I-Language
variant	O
eventually	O
replaced	O
ConEuc	O
in	O
most	O
applications	O
.	O
</s>
