<s>
The	O
Cray	B-Operating_System
Time	I-Operating_System
Sharing	I-Operating_System
System	I-Operating_System
,	O
also	O
known	O
in	O
the	O
Cray	O
user	O
community	O
as	O
CTSS	O
,	O
was	O
developed	O
as	O
an	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
Cray-1	B-Device
or	O
Cray	B-Device
X-MP	I-Device
line	O
of	O
supercomputers	B-Architecture
in	O
1978	O
.	O
</s>
<s>
CTSS	O
was	O
popular	O
with	O
Cray	O
sites	O
in	O
the	O
United	O
States	O
Department	O
of	O
Energy	O
(	O
DOE	O
)	O
,	O
but	O
was	O
used	O
by	O
several	O
other	O
Cray	O
sites	O
,	O
such	O
as	O
the	O
San	O
Diego	O
Supercomputing	B-Architecture
Center	O
.	O
</s>
<s>
The	O
predecessor	O
of	O
CTSS	O
was	O
the	O
Livermore	B-Operating_System
Time	I-Operating_System
Sharing	I-Operating_System
System	I-Operating_System
(	O
LTSS	O
)	O
which	O
ran	O
on	O
Control	O
Data	O
CDC	B-Device
7600	I-Device
line	O
of	O
supercomputers	B-Architecture
.	O
</s>
<s>
The	O
first	O
compiler	B-Language
was	O
known	O
as	O
LRLTRAN	O
,	O
for	O
Lawrence	O
Radiation	O
Laboratory	O
forTRAN	O
,	O
a	O
FORTRAN	O
66	O
programming	O
language	O
but	O
with	O
dynamic	B-General_Concept
memory	I-General_Concept
and	O
other	O
features	O
.	O
</s>
<s>
The	O
Cray	O
version	O
,	O
including	O
automatic	B-General_Concept
vectorization	I-General_Concept
,	O
was	O
known	O
as	O
CVC	O
,	O
pronounced	O
"	O
Civic	O
"	O
like	O
the	O
Honda	O
car	O
of	O
the	O
period	O
,	O
for	O
Cray	O
Vector	O
Compiler	B-Language
.	O
</s>
<s>
Some	O
controversy	O
existed	O
at	O
LASL	O
with	O
the	O
first	O
attempt	O
to	O
develop	O
an	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
Cray-1	B-Device
named	O
DEIMOS	O
,	O
a	O
message-passing	O
,	O
Unix-like	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
by	O
Forrest	O
Basket	O
.	O
</s>
<s>
DEIMOS	O
had	O
initial	O
"	O
teething	O
"	O
problems	O
common	O
to	O
the	O
performance	O
of	O
all	O
early	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
This	O
left	O
a	O
bad	O
taste	O
for	O
Unix-like	B-Operating_System
systems	I-Operating_System
at	O
the	O
National	O
Laboratories	O
and	O
with	O
the	O
manufacturer	O
,	O
Cray	O
Research	O
,	O
Inc.	O
,	O
of	O
the	O
hardware	O
who	O
went	O
on	O
to	O
develop	O
their	O
own	O
batch	O
oriented	O
operating	B-General_Concept
system	I-General_Concept
,	O
COS	O
(	O
Cray	B-Operating_System
Operating	I-Operating_System
System	I-Operating_System
)	O
and	O
their	O
own	O
vectorizing	O
Fortran	O
compiler	B-Language
named	O
"	O
CFT	O
"	O
(	O
Cray	O
ForTran	O
)	O
both	O
written	O
in	O
the	O
Cray	O
Assembly	O
Language	O
(	O
CAL	O
)	O
.	O
</s>
<s>
CTSS	O
had	O
the	O
misfortune	O
to	O
have	O
certain	O
constants	O
,	O
structures	O
,	O
and	O
lacking	O
certain	O
networking	O
facilities	O
(	O
TCP/IP	B-Protocol
)	O
which	O
were	O
optimized	O
to	O
be	O
Cray-1	B-Device
architecture-dependent	O
without	O
extensive	O
rework	O
when	O
larger	O
memory	O
supercomputers	B-Architecture
like	O
the	O
Cray-2	O
and	O
the	O
Cray	O
Y-MP	O
came	O
into	O
use	O
.	O
</s>
<s>
An	O
attempt	O
to	O
succeed	O
CTSS	O
was	O
started	O
by	O
LLNL	O
named	O
NLTSS	B-Operating_System
(	O
New	B-Operating_System
Livermore	I-Operating_System
Time	I-Operating_System
Sharing	I-Operating_System
System	I-Operating_System
)	O
to	O
embody	O
advanced	O
concepts	O
for	O
operating	B-General_Concept
systems	I-General_Concept
to	O
better	O
integrate	O
communication	O
using	O
a	O
new	O
network	O
protocol	O
named	O
LINCS	B-Device
while	O
also	O
keeping	O
the	O
best	O
features	O
of	O
CTSS	O
.	O
</s>
<s>
NLTSS	B-Operating_System
followed	O
the	O
development	O
fate	O
of	O
many	O
operating	B-General_Concept
systems	I-General_Concept
and	O
only	O
briefly	O
ran	O
on	O
period	O
Cray	O
hardware	O
of	O
the	O
late	O
1980s	O
.	O
</s>
<s>
on	O
Operating	B-General_Concept
Systems	I-General_Concept
Proceedings	O
)	O
.	O
</s>
