<s>
This	O
article	O
covers	O
the	O
History	B-Application
of	I-Application
CP/CMS	I-Application
—	O
the	O
historical	O
context	O
in	O
which	O
the	O
IBM	O
time-sharing	B-General_Concept
virtual	B-Architecture
machine	I-Architecture
operating	B-General_Concept
system	I-General_Concept
was	O
built	O
.	O
</s>
<s>
CP/CMS	B-Application
development	O
occurred	O
in	O
a	O
complex	O
political	O
and	O
technical	O
milieu	O
.	O
</s>
<s>
The	O
seminal	O
first-generation	O
time-sharing	B-General_Concept
system	I-General_Concept
was	O
CTSS	B-Operating_System
,	O
first	O
demonstrated	O
at	O
MIT	O
in	O
1961	O
and	O
in	O
production	O
use	O
from	O
1964	O
to	O
1974	O
.	O
</s>
<s>
It	O
paved	O
the	O
way	O
for	O
Multics	B-Application
,	O
CP/CMS	B-Application
,	O
and	O
all	O
other	O
time-sharing	B-General_Concept
environments	O
.	O
</s>
<s>
Time-sharing	B-General_Concept
concepts	O
were	O
first	O
articulated	O
in	O
the	O
late	O
50s	O
,	O
particularly	O
as	O
a	O
way	O
to	O
meet	O
the	O
needs	O
of	O
scientific	O
computing	O
.	O
</s>
<s>
At	O
the	O
time	O
,	O
computers	O
were	O
primarily	O
used	O
for	O
batch	B-General_Concept
processing	I-General_Concept
—	O
where	O
jobs	O
were	O
submitted	O
on	O
punch	O
cards	O
,	O
and	O
run	O
in	O
sequence	O
.	O
</s>
<s>
Time-sharing	B-General_Concept
let	O
users	O
interact	O
directly	O
with	O
a	O
computer	O
,	O
so	O
that	O
calculation	O
and	O
simulation	O
results	O
could	O
be	O
seen	O
immediately	O
.	O
</s>
<s>
Scientific	O
users	O
quickly	O
embraced	O
the	O
concept	O
of	O
time-sharing	B-General_Concept
,	O
and	O
pressured	O
computer	O
vendors	O
such	O
as	O
IBM	O
for	O
improved	O
time-sharing	B-General_Concept
capabilities	O
.	O
</s>
<s>
MIT	O
researchers	O
spearheaded	O
this	O
effort	O
,	O
launching	O
Project	O
MAC	O
,	O
which	O
was	O
intended	O
to	O
develop	O
the	O
next	O
generation	O
of	O
time-sharing	B-General_Concept
technology	O
and	O
which	O
would	O
ultimately	O
build	O
Multics	B-Application
,	O
an	O
extremely	O
feature-rich	B-Architecture
time-sharing	B-General_Concept
system	I-General_Concept
that	O
would	O
later	O
inspire	O
the	O
initial	O
development	O
of	O
UNIX	B-Application
.	O
</s>
<s>
Most	O
early	O
time-sharing	B-General_Concept
systems	I-General_Concept
sidestepped	O
these	O
problems	O
by	O
giving	O
users	O
new	O
or	O
modified	O
languages	O
,	O
such	O
as	O
Dartmouth	B-Language
BASIC	I-Language
,	O
which	O
were	O
accessed	O
through	O
interpreters	O
or	O
restricted	O
execution	O
contexts	O
.	O
</s>
<s>
However	O
,	O
IBM	O
's	O
proposal	O
was	O
not	O
well	O
received	O
:	O
To	O
IBM	O
's	O
surprise	O
,	O
MIT	O
chose	O
General	O
Electric	O
as	O
the	O
Multics	B-Application
system	O
vendor	O
.	O
</s>
<s>
The	O
fallout	O
from	O
this	O
event	O
led	O
directly	O
to	O
CP/CMS	B-Application
.	O
</s>
<s>
IBM	O
embarked	O
on	O
a	O
very	O
risky	O
undertaking	O
:	O
the	O
System/360	B-Application
.	O
</s>
<s>
This	O
product	O
line	O
was	O
intended	O
to	O
replace	O
IBM	O
's	O
diverse	O
earlier	O
offerings	O
,	O
including	O
the	O
IBM	B-Device
7000	I-Device
series	I-Device
,	O
the	O
canceled	O
IBM	B-Device
8000	I-Device
series	O
,	O
the	O
IBM	B-Device
1130	I-Device
series	O
,	O
and	O
various	O
other	O
specialized	O
machines	O
used	O
for	O
scientific	O
and	O
other	O
applications	O
.	O
</s>
<s>
The	O
System/360	B-Application
would	O
span	O
an	O
unprecedented	O
range	O
of	O
processing	O
power	O
,	O
memory	O
size	O
,	O
device	O
support	O
,	O
and	O
cost	O
;	O
and	O
more	O
important	O
,	O
it	O
was	O
based	O
on	O
a	O
pledge	O
of	O
backward	B-General_Concept
compatibility	I-General_Concept
,	O
such	O
that	O
any	O
customer	O
could	O
move	O
software	O
to	O
a	O
new	O
system	O
without	O
modification	O
.	O
</s>
<s>
Before	O
System/360	B-Application
,	O
each	O
computer	O
model	O
often	O
had	O
its	O
own	O
specific	O
devices	O
and	O
programs	O
that	O
could	O
not	O
be	O
used	O
with	O
other	O
systems	O
.	O
</s>
<s>
With	O
the	O
S/360	B-Application
,	O
IBM	O
wanted	O
to	O
offer	O
a	O
huge	O
range	O
of	O
computer	O
systems	O
,	O
all	O
sharing	O
a	O
single	O
processor	O
architecture	O
,	O
instruction	O
set	O
,	O
I/O	O
interface	O
,	O
and	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
At	O
the	O
start	O
of	O
the	O
System/360	B-Application
project	O
,	O
IBM	O
did	O
not	O
fully	O
appreciate	O
the	O
amount	O
of	O
risk	O
involved	O
.	O
</s>
<s>
System/360	B-Application
ultimately	O
gave	O
IBM	O
total	O
dominance	O
over	O
the	O
computer	O
industry	O
;	O
but	O
at	O
first	O
,	O
it	O
nearly	O
put	O
IBM	O
out	O
of	O
business	O
.	O
</s>
<s>
It	O
was	O
during	O
the	O
period	O
of	O
System/360	B-Application
panic	O
that	O
Project	O
MAC	O
asked	O
IBM	O
to	O
provide	O
computers	O
with	O
extensive	O
time-sharing	B-General_Concept
capabilities	O
.	O
</s>
<s>
This	O
was	O
not	O
the	O
direction	O
the	O
System/360	B-Application
project	O
was	O
going	O
.	O
</s>
<s>
Time-sharing	B-General_Concept
was	O
n't	O
seen	O
as	O
important	O
to	O
IBM	O
's	O
main	O
customer	O
base	O
;	O
batch	B-General_Concept
processing	I-General_Concept
was	O
key	O
.	O
</s>
<s>
Moreover	O
,	O
time-sharing	B-General_Concept
was	O
new	O
ground	O
.	O
</s>
<s>
Many	O
of	O
the	O
concepts	O
involved	O
,	O
such	O
as	O
virtual	B-Architecture
memory	I-Architecture
,	O
remained	O
unproven	O
.	O
</s>
<s>
For	O
example	O
:	O
At	O
the	O
time	O
,	O
nobody	O
could	O
explain	O
why	O
the	O
troubled	O
Manchester/Ferranti	B-Device
Atlas	I-Device
virtual	B-Architecture
memory	I-Architecture
"	O
did	O
n't	O
work	O
"	O
.	O
</s>
<s>
This	O
was	O
later	O
explained	O
as	O
due	O
to	O
thrashing	B-General_Concept
,	O
based	O
on	O
CP/CMS	B-Application
and	O
M44/44X	B-Device
research	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
IBM	O
's	O
System/360	B-Application
announcement	O
in	O
April	O
1964	O
did	O
not	O
include	O
key	O
elements	O
sought	O
by	O
the	O
time-sharing	B-General_Concept
advocates	O
,	O
particularly	O
virtual	B-Architecture
memory	I-Architecture
capabilities	O
.	O
</s>
<s>
The	O
System/360	B-Application
design	O
team	O
met	O
with	O
Project	O
MAC	O
researchers	O
,	O
and	O
listened	O
to	O
their	O
objections	O
;	O
but	O
IBM	O
chose	O
another	O
path	O
.	O
</s>
<s>
IBM	O
fully	O
expected	O
to	O
win	O
the	O
Project	O
MAC	O
competition	O
,	O
and	O
to	O
retain	O
its	O
perceived	O
lead	O
in	O
scientific	O
computing	O
and	O
time-sharing	B-General_Concept
.	O
</s>
<s>
IBM	O
had	O
received	O
intelligence	O
that	O
MIT	O
was	O
leaning	O
toward	O
the	O
GE	O
proposal	O
,	O
which	O
was	O
for	O
a	O
modified	O
600-series	O
computer	O
with	O
virtual	B-Architecture
memory	I-Architecture
hardware	O
and	O
other	O
enhancements	O
;	O
this	O
would	O
eventually	O
become	O
the	O
GE	B-Device
645	I-Device
.	O
</s>
<s>
IBM	O
proposed	O
a	O
modified	O
S/360	B-Application
that	O
would	O
include	O
a	O
virtual	B-Architecture
memory	I-Architecture
device	O
called	O
the	O
"	O
Blaauw	O
Box	O
"	O
a	O
component	O
that	O
had	O
been	O
designed	O
for	O
,	O
but	O
not	O
included	O
in	O
,	O
the	O
S/360	B-Application
.	O
</s>
<s>
The	O
modified	O
S/360	B-Application
was	O
seen	O
as	O
too	O
different	O
from	O
the	O
rest	O
of	O
the	O
S/360	B-Application
line	O
;	O
MIT	O
did	O
not	O
want	O
to	O
use	O
a	O
customized	O
or	O
special-purpose	O
computer	O
for	O
MULTICS	B-Application
,	O
but	O
sought	O
hardware	O
that	O
would	O
be	O
widely	O
available	O
.	O
</s>
<s>
GE	O
was	O
prepared	O
to	O
make	O
a	O
large	O
commitment	O
to	O
time-sharing	B-General_Concept
,	O
while	O
IBM	O
was	O
seen	O
as	O
obstructive	O
.	O
</s>
<s>
Bell	O
Laboratories	O
,	O
another	O
important	O
IBM	O
customer	O
,	O
soon	O
made	O
the	O
same	O
decision	O
,	O
and	O
rejected	O
the	O
S/360	B-Application
for	O
time-sharing	B-General_Concept
.	O
</s>
<s>
Rasmussen	O
remained	O
committed	O
to	O
time-sharing	B-General_Concept
,	O
and	O
wanted	O
to	O
earn	O
back	O
the	O
confidence	O
of	O
MIT	O
and	O
other	O
researchers	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
he	O
made	O
a	O
bold	O
decision	O
:	O
The	O
now-idle	O
CSC	O
team	O
would	O
build	O
a	O
time-sharing	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
for	O
the	O
S/360	B-Application
.	O
</s>
<s>
Robert	O
Creasy	O
left	O
Project	O
MAC	O
to	O
lead	O
the	O
CSC	O
team	O
,	O
which	O
promptly	O
began	O
work	O
on	O
what	O
was	O
to	O
become	O
CP-40	B-Application
,	O
the	O
first	O
successful	O
virtual	B-Architecture
machine	I-Architecture
operating	B-General_Concept
system	I-General_Concept
based	O
on	O
fully	O
virtualized	O
hardware	O
.	O
</s>
<s>
IBM	O
created	O
a	O
corporate	O
task	O
force	O
to	O
find	O
a	O
satisfactory	O
way	O
to	O
meet	O
customer	O
time-sharing	B-General_Concept
requirements	O
.	O
</s>
<s>
The	O
team	O
,	O
which	O
included	O
key	O
staff	O
from	O
CSC	O
,	O
designed	O
a	O
new	O
S/360	B-Application
model	O
that	O
was	O
closer	O
to	O
the	O
goals	O
of	O
the	O
MIT	O
researchers	O
.	O
</s>
<s>
This	O
was	O
to	O
become	O
the	O
IBM	B-Device
System/360	I-Device
-67	I-Device
,	O
announced	O
in	O
August	O
1965	O
and	O
shipped	O
in	O
July	O
1966	O
.	O
</s>
<s>
IBM	O
's	O
announcement	O
also	O
included	O
a	O
new	O
time-sharing	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
,	O
TSS/360	B-Application
,	O
optimistically	O
scheduled	O
for	O
June	O
1967	O
release	O
.	O
</s>
<s>
CSC	O
soon	O
submitted	O
a	O
successful	O
proposal	O
to	O
MIT	O
's	O
Lincoln	O
Laboratory	O
for	O
a	O
S/360	B-Device
-67	I-Device
,	O
marking	O
an	O
improvement	O
in	O
IBM	O
's	O
credibility	O
at	O
MIT	O
.	O
</s>
<s>
By	O
committing	O
to	O
a	O
"	O
real	O
"	O
time-sharing	B-General_Concept
product	O
,	O
rather	O
than	O
a	O
customized	O
RPQ	O
system	O
,	O
IBM	O
was	O
showing	O
the	O
kind	O
of	O
commitment	O
MIT	O
found	O
with	O
GE	O
.	O
</s>
<s>
CSC	O
also	O
continued	O
work	O
on	O
CP-40	B-Application
,	O
ostensibly	O
to	O
provide	O
research	O
input	O
to	O
the	O
S/360	B-Device
-67	I-Device
team	O
—	O
but	O
also	O
because	O
the	O
CSC	O
team	O
had	O
grown	O
skeptical	O
about	O
the	O
TSS	B-Application
project	O
,	O
which	O
faced	O
a	O
very	O
aggressive	O
schedule	O
and	O
lofty	O
goals	O
.	O
</s>
<s>
Since	O
a	O
S/360	B-Device
-67	I-Device
would	O
not	O
be	O
available	O
to	O
CSC	O
for	O
some	O
time	O
,	O
the	O
team	O
conceived	O
an	O
ingenious	O
stopgap	O
measure	O
:	O
building	O
their	O
own	O
virtual-memory	O
S/360	B-Application
.	O
</s>
<s>
They	O
designed	O
a	O
set	O
of	O
custom	O
hardware	O
and	O
microcode	O
changes	O
that	O
could	O
be	O
implemented	O
on	O
a	O
S/360	B-Application
-40	O
,	O
providing	O
a	O
comparable	O
platform	O
capable	O
of	O
supporting	O
CP-40	B-Application
'	O
s	O
virtual	B-Architecture
machine	I-Architecture
architecture	O
.	O
</s>
<s>
Actual	O
CP-40	B-Application
and	O
CMS	O
development	O
began	O
in	O
mid	O
1965	O
,	O
even	O
before	O
the	O
arrival	O
of	O
their	O
modified	O
S/360	B-Application
-40	O
.	O
</s>
<s>
First	O
production	O
use	O
of	O
CP-40	B-Application
was	O
in	O
January	O
1967	O
.	O
</s>
<s>
The	O
TSS	B-Application
project	O
,	O
in	O
the	O
meantime	O
,	O
was	O
running	O
late	O
and	O
struggling	O
with	O
problems	O
.	O
</s>
<s>
CSC	O
personnel	O
became	O
increasingly	O
convinced	O
that	O
CP/CMS	B-Application
was	O
the	O
correct	O
architecture	O
for	O
S/360	B-Application
time-sharing	B-General_Concept
.	O
</s>
<s>
In	O
September	O
1966	O
,	O
CSC	O
staff	O
began	O
the	O
conversion	O
of	O
CP-40	B-Application
and	O
CMS	O
to	O
run	O
on	O
the	O
S/360	B-Device
-67	I-Device
.	O
</s>
<s>
CP-67	O
was	O
a	O
significant	O
reimplementation	O
of	O
CP-40	B-Application
;	O
Varian	O
reports	O
that	O
the	O
design	O
was	O
"	O
generalized	O
substantially	O
,	O
to	O
allow	O
a	O
variable	O
number	O
of	O
virtual	B-Architecture
machines	I-Architecture
,	O
with	O
larger	O
virtual	B-Architecture
memories	I-Architecture
"	O
,	O
that	O
new	O
data	O
structures	O
replaced	O
"	O
the	O
control	O
blocks	O
describing	O
the	O
virtual	B-Architecture
machines	I-Architecture
 [ which ] 	O
had	O
been	O
a	O
hard-coded	O
part	O
of	O
the	O
nucleus	B-Operating_System
"	O
,	O
that	O
CP-67	O
added	O
"	O
the	O
concept	O
of	O
free	O
storage	O
,	O
so	O
that	O
control	O
blocks	O
could	O
be	O
allocated	O
dynamically	O
"	O
,	O
and	O
that	O
"	O
the	O
inter-module	O
linkage	O
was	O
also	O
reworked	O
,	O
and	O
the	O
code	O
was	O
made	O
re-entrant.	O
"	O
</s>
<s>
Since	O
CSC	O
's	O
-67	O
would	O
not	O
arrive	O
for	O
some	O
time	O
,	O
CSC	O
further	O
modified	O
the	O
microcode	O
on	O
its	O
own	O
customized	O
S/360	B-Application
-40	O
to	O
simulate	O
the	O
S/360	B-Device
-67	I-Device
particularly	O
its	O
different	O
approach	O
to	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
CSC	O
repeatedly	O
and	O
successfully	O
used	O
simulation	O
to	O
work	O
around	O
the	O
absence	O
of	O
hardware	O
:	O
when	O
waiting	O
for	O
its	O
modified	O
S/360	B-Application
-40	O
,	O
for	O
its	O
S/360	B-Device
-67	I-Device
,	O
and	O
later	O
for	O
the	O
first	O
S/370	B-Device
prototypes	O
.	O
</s>
<s>
This	O
can	O
be	O
seen	O
as	O
a	O
logical	O
outgrowth	O
of	O
"	O
virtual	B-Architecture
machine	I-Architecture
"	O
thinking	O
.	O
</s>
<s>
During	O
this	O
period	O
,	O
early	O
testing	O
of	O
CP-67	O
was	O
also	O
done	O
at	O
sites	O
where	O
S/360	B-Device
-67	I-Device
hardware	O
was	O
available	O
notably	O
IBM	O
's	O
Yorktown	O
Heights	O
lab	O
and	O
MIT	O
's	O
Lincoln	O
Laboratory	O
.	O
</s>
<s>
Observers	O
of	O
CP-67	O
at	O
Lincoln	O
Labs	O
,	O
already	O
frustrated	O
with	O
severe	O
TSS	B-Application
problems	O
,	O
were	O
very	O
impressed	O
by	O
CP-67	O
.	O
</s>
<s>
They	O
insisted	O
that	O
IBM	O
provide	O
them	O
a	O
copy	O
of	O
CP/CMS	B-Application
.	O
</s>
<s>
According	O
to	O
Varian	O
,	O
this	O
demand	O
"	O
rocked	O
the	O
whole	O
company	O
"	O
,	O
which	O
had	O
invested	O
so	O
heavily	O
in	O
TSS	B-Application
.	O
</s>
<s>
Varian	O
and	O
others	O
speculate	O
that	O
this	O
chain	O
of	O
events	O
could	O
have	O
been	O
"	O
engineered	O
"	O
by	O
Rasmussen	O
,	O
as	O
a	O
"	O
subterfuge	O
"	O
to	O
motivate	O
IBM	O
's	O
continued	O
funding	O
CSC	O
's	O
work	O
on	O
the	O
"	O
counter-strategic	O
"	O
CP/CMS	B-Application
,	O
which	O
he	O
"	O
was	O
told	O
several	O
times	O
to	O
kill	O
"	O
.	O
</s>
<s>
By	O
April	O
1967	O
just	O
a	O
few	O
months	O
after	O
CP-40	B-Application
went	O
into	O
production	O
CP/CMS	B-Application
was	O
already	O
in	O
daily	O
use	O
at	O
Lincoln	O
Labs	O
.	O
</s>
<s>
Lincoln	O
Lab	O
personnel	O
worked	O
closely	O
with	O
CSC	O
in	O
improving	O
CP/CMS	B-Application
.	O
</s>
<s>
At	O
around	O
the	O
same	O
time	O
,	O
Union	O
Carbide	O
,	O
another	O
influential	O
IBM	O
customer	O
,	O
followed	O
the	O
same	O
path	O
deciding	O
to	O
run	O
CP/CMS	B-Application
,	O
to	O
send	O
personnel	O
to	O
work	O
with	O
CSC	O
,	O
and	O
to	O
contribute	O
to	O
the	O
CP/CMS	B-Application
development	O
effort	O
.	O
</s>
<s>
CP-40	B-Application
,	O
CP-67	O
,	O
and	O
CMS	O
were	O
essentially	O
research	O
systems	O
at	O
the	O
time	O
,	O
built	O
away	O
from	O
IBM	O
's	O
mainstream	O
product	O
organizations	O
,	O
with	O
active	O
involvement	O
of	O
outside	O
researchers	O
.	O
</s>
<s>
Robert	O
Creasy	O
,	O
the	O
CP-40	B-Application
project	O
leader	O
,	O
later	O
wrote	O
:	O
</s>
<s>
<	O
blockquote>The	O
design	O
of	O
CP/CMS	B-Application
 [ was ] 	O
by	O
a	O
small	O
and	O
varied	O
software	O
research	O
and	O
development	O
group	O
for	O
its	O
own	O
use	O
and	O
support	O
…	O
 [ and ] 	O
for	O
experimenting	O
with	O
time-sharing	B-General_Concept
system	I-General_Concept
design	O
....	O
</s>
<s>
TSS	B-Application
,	O
in	O
the	O
meantime	O
,	O
described	O
by	O
Varian	O
as	O
an	O
"	O
elegant	O
and	O
very	O
ambitious	O
system	O
,	O
"	O
was	O
exhibiting	O
"	O
serious	O
stability	O
and	O
performance	O
problems	O
,	O
for	O
it	O
had	O
been	O
snatched	O
from	O
its	O
nest	O
too	O
young	O
.	O
</s>
<s>
cit.	O
,	O
p	O
.	O
17	O
—	O
TSS	B-Application
"	O
snatched	O
from	O
its	O
nest	O
too	O
young	O
"	O
In	O
February	O
1968	O
,	O
at	O
the	O
time	O
of	O
SHARE	O
30	O
,	O
there	O
were	O
eighteen	O
S/360	B-Device
-67	I-Device
sites	O
attempting	O
to	O
run	O
TSS	B-Application
.	O
</s>
<s>
During	O
the	O
conference	O
,	O
IBM	O
announced	O
via	O
"	O
blue	O
letter	O
"	O
that	O
TSS	B-Application
was	O
being	O
decommitted	O
—	O
a	O
great	O
blow	O
to	O
the	O
time-sharing	B-General_Concept
community	O
.	O
</s>
<s>
This	O
decision	O
would	O
be	O
temporarily	O
reversed	O
,	O
and	O
TSS	B-Application
would	O
not	O
be	O
scrapped	O
until	O
1971	O
.	O
</s>
<s>
However	O
,	O
CP/CMS	B-Application
soon	O
began	O
gaining	O
attention	O
as	O
a	O
viable	O
alternative	O
.	O
</s>
<s>
May	O
1968	O
:	O
Version	O
1	O
of	O
CP/CMS	B-Application
was	O
released	O
to	O
eight	O
installations	O
.	O
</s>
<s>
It	O
was	O
made	O
available	O
as	O
part	O
of	O
the	O
IBM	B-Application
Type-III	I-Application
Library	I-Application
in	O
June	O
.	O
</s>
<s>
Shortly	O
thereafter	O
,	O
two	O
time-sharing	B-General_Concept
businesses	O
were	O
launched	O
based	O
on	O
the	O
resale	O
of	O
CP/CMS	B-Application
:	O
National	O
CSS	O
and	O
IDC	O
.	O
</s>
<s>
These	O
ventures	O
took	O
key	O
personnel	O
from	O
CSC	O
,	O
Lincoln	O
Labs	O
,	O
and	O
Union	O
Carbide	O
;	O
and	O
they	O
drew	O
attention	O
to	O
the	O
viability	O
of	O
CP/CMS	B-Application
,	O
the	O
S/360	B-Device
-67	I-Device
,	O
and	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
April	O
1969	O
:	O
CP/CMS	B-Application
had	O
been	O
installed	O
at	O
fifteen	O
sites	O
.	O
</s>
<s>
June	O
1969	O
:	O
Version	O
2	O
of	O
CP/CMS	B-Application
was	O
released	O
.	O
</s>
<s>
November	O
1971	O
:	O
Version	O
3.1	O
of	O
CP/CMS	B-Application
was	O
released	O
,	O
capable	O
of	O
supporting	O
sixty	O
CMS	O
users	O
on	O
a	O
-67	O
–	O
impressive	O
performance	O
.	O
</s>
<s>
Early	O
1972	O
:	O
CP/CMS	B-Application
Version	O
3.2	O
was	O
released	O
,	O
a	O
maintenance	O
release	O
with	O
no	O
new	O
functions	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
the	O
S/360	B-Device
-67	I-Device
,	O
software	O
was	O
"	O
bundled	O
"	O
into	O
computer	O
hardware	O
purchases	O
;	O
see	O
"	O
IBM	O
's	O
unbundling	O
of	O
software	O
and	O
services	O
"	O
.	O
</s>
<s>
In	O
particular	O
,	O
IBM	O
operating	B-General_Concept
systems	I-General_Concept
were	O
available	O
without	O
additional	O
charge	O
to	O
IBM	O
customers	O
.	O
</s>
<s>
CP/CMS	B-Application
was	O
unusual	O
in	O
that	O
it	O
was	O
delivered	O
as	O
unsupported	O
Type-III	B-Application
software	I-Application
in	O
source	O
code	O
form	O
–	O
meaning	O
that	O
CP/CMS	B-Application
sites	O
ran	O
an	O
unsupported	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
need	O
for	O
self-support	O
and	O
community	O
support	O
helped	O
lead	O
to	O
the	O
creation	O
of	O
a	O
strong	O
S/360	B-Device
-67	I-Device
and	O
CP/CMS	B-Application
user	O
communities	O
,	O
precursors	O
to	O
the	O
open	B-License
source	I-License
movement	O
.	O
</s>
<s>
In	O
the	O
summer	O
of	O
1970	O
,	O
the	O
CP/CMS	B-Application
team	O
had	O
begun	O
work	O
on	O
a	O
System/370	B-Device
version	O
of	O
CP/CMS	B-Application
;	O
this	O
would	O
become	O
VM/370	B-Application
.	O
</s>
<s>
CP-370	B-Application
proved	O
vital	O
to	O
the	O
S/370	B-Device
project	O
,	O
by	O
providing	O
a	O
usable	O
simulation	O
of	O
a	O
S/370	B-Device
on	O
S/360	B-Device
-67	I-Device
hardware	O
–	O
a	O
reprise	O
of	O
CSC	O
's	O
earlier	O
hardware	O
simulation	O
strategies	O
.	O
</s>
<s>
This	O
approach	O
enabled	O
S/370	B-Device
development	O
and	O
testing	O
before	O
S/370	B-Device
hardware	O
was	O
available	O
.	O
</s>
<s>
A	O
shortage	O
of	O
prototype	O
S/370s	B-Device
was	O
causing	O
critical	O
delays	O
for	O
the	O
MVS	O
project	O
,	O
in	O
particular	O
.	O
</s>
<s>
This	O
remarkable	O
technical	O
feat	O
transformed	O
MVS	O
development	O
,	O
won	O
an	O
award	O
for	O
the	O
CP-370	B-Application
developers	O
,	O
and	O
probably	O
rescued	O
the	O
CP	O
project	O
from	O
extinction	O
,	O
despite	O
aggressive	O
efforts	O
to	O
cancel	O
the	O
project	O
.	O
</s>
<s>
August	O
1972	O
marked	O
the	O
end	O
of	O
CP/CMS	B-Application
,	O
with	O
IBM	O
's	O
"	O
System/370	B-Device
Advanced	O
Function	O
"	O
announcement	O
.	O
</s>
<s>
This	O
included	O
:	O
the	O
new	O
S/370	B-Device
-158	O
and	O
-168	O
;	O
address	O
relocation	O
hardware	O
on	O
all	O
S/370s	B-Device
;	O
and	O
four	O
new	O
operating	B-General_Concept
systems	I-General_Concept
:	O
DOS/VS	O
(	O
DOS	O
with	O
virtual	B-Architecture
storage	I-Architecture
)	O
,	O
OS/VS1	O
(	O
OS/MFT	O
with	O
virtual	B-Architecture
storage	I-Architecture
)	O
,	O
OS/VS2	O
(	O
OS/MVT	O
with	O
virtual	B-Architecture
storage	I-Architecture
,	O
which	O
would	O
grow	O
into	O
SVS	O
and	O
MVS	O
)	O
,	O
and	O
VM/370	B-Application
—	O
the	O
re-implemented	O
CP/CMS	B-Application
.	O
</s>
<s>
By	O
this	O
time	O
the	O
VM	B-Application
and	O
CP/CMS	B-Application
development	O
team	O
had	O
swelled	O
to	O
110	O
people	O
,	O
including	O
documenters	O
.	O
</s>
<s>
VM/370	B-Application
was	O
now	O
a	O
real	O
IBM	O
system	O
,	O
no	O
longer	O
part	O
of	O
the	O
IBM	B-Application
Type-III	I-Application
Library	I-Application
.	O
</s>
<s>
Source	O
code	O
distribution	O
continued	O
for	O
several	O
releases	O
,	O
however	O
;	O
see	O
CP/CMS	B-Application
as	O
free	O
software	O
for	O
details	O
.	O
</s>
<s>
In	O
1968	O
,	O
the	O
principals	O
of	O
a	O
small	O
consulting	O
firm	O
in	O
Connecticut	O
called	O
Computer	O
Software	O
Systems	O
had	O
the	O
audacious	O
idea	O
of	O
leasing	O
an	O
IBM	B-Device
System/360	I-Device
-67	I-Device
to	O
run	O
CP/CMS	B-Application
and	O
reselling	O
computer	O
time	O
.	O
</s>
<s>
The	O
third	O
and	O
fourth	O
employees	O
were	O
Dick	O
Orenstein	O
,	O
one	O
of	O
the	O
authors	O
of	O
CTSS	B-Operating_System
,	O
and	O
Dick	O
Bayles	O
,	O
from	O
CSC	O
–	O
the	O
primary	O
architect	O
of	O
CP-67	O
.	O
</s>
<s>
Other	O
key	O
hires	O
from	O
the	O
CP/CMS	B-Application
world	O
included	O
Harold	O
Feinleib	O
,	O
Mike	O
Field	O
,	O
and	O
Robert	O
Jesurum	O
(	O
Bob	O
Jay	O
)	O
.	O
</s>
<s>
By	O
late	O
November	O
1968	O
,	O
having	O
persuaded	O
IBM	O
to	O
accept	O
the	O
order	O
(	O
no	O
small	O
feat	O
)	O
and	O
secured	O
initial	O
funding	O
,	O
CSS	O
took	O
delivery	O
on	O
their	O
first	O
S/360	B-Device
-67	I-Device
.	O
</s>
<s>
CSS	O
quickly	O
discovered	O
that	O
,	O
by	O
selling	O
every	O
available	O
virtual	B-Architecture
machine	I-Architecture
minute	O
at	O
published	O
prices	O
,	O
they	O
could	O
barely	O
take	O
in	O
enough	O
revenue	O
to	O
pay	O
the	O
machine	O
lease	O
.	O
</s>
<s>
A	O
whirlwind	O
development	O
program	O
followed	O
,	O
ramping	O
up	O
CP/CMS	B-Application
performance	O
to	O
the	O
point	O
where	O
it	O
could	O
be	O
resold	O
profitably	O
.	O
</s>
<s>
This	O
began	O
a	O
fork	B-Application
of	O
CP/CMS	B-Application
source	O
code	O
that	O
evolved	O
independently	O
for	O
some	O
fifteen	O
years	O
.	O
</s>
<s>
This	O
operating	B-General_Concept
system	I-General_Concept
was	O
soon	O
renamed	O
VP/CSS	B-Application
;	O
the	O
company	O
went	O
public	O
,	O
and	O
was	O
renamed	O
National	O
CSS	O
.	O
</s>
<s>
Although	O
VP/CSS	B-Application
shared	O
much	O
with	O
its	O
CP/CMS	B-Application
parent	O
and	O
its	O
VM/370	B-Application
sibling	O
,	O
it	O
diverged	O
from	O
them	O
in	O
many	O
important	O
ways	O
.	O
</s>
<s>
VP/CSS	B-Application
soon	O
became	O
known	O
for	O
routinely	O
supporting	O
two	O
to	O
three	O
times	O
as	O
many	O
interactive	O
users	O
as	O
on	O
comparable	O
VM	B-Application
systems	O
.	O
</s>
<s>
Early	O
NCSS	O
enhancements	O
involved	O
such	O
areas	O
as	O
page	O
migration	O
,	O
dispatching	O
,	O
file	O
system	O
,	O
device	O
support	O
,	O
and	O
efficient	O
fast-path	O
hypervisor	B-Operating_System
functions	O
accessed	O
via	O
the	O
diagnose	O
(	O
DIAG	O
)	O
instruction	O
.	O
</s>
<s>
Later	O
features	O
included	O
a	O
packet-switched	B-Protocol
network	I-Protocol
,	O
FILEDEF-level	O
(	O
pipe	B-Operating_System
)	O
interprocess/intermachine	O
communication	O
,	O
and	O
database	O
integration	O
.	O
</s>
<s>
Similar	O
features	O
also	O
appeared	O
in	O
the	O
VM	B-Application
implementation	O
.	O
</s>
<s>
The	O
VP/CSS	B-Application
platform	O
remained	O
in	O
use	O
through	O
at	O
least	O
the	O
mid-80s	O
.	O
</s>
<s>
NCSS	O
was	O
acquired	O
by	O
Dun	O
&	O
Bradstreet	O
in	O
1979	O
;	O
renamed	O
DBCS	O
(	O
Dun	O
&	O
Bradstreet	O
Computer	O
Services	O
)	O
;	O
increased	O
its	O
focus	O
on	O
the	O
NOMAD	B-Application
product	O
;	O
changed	O
its	O
business	O
strategy	O
to	O
embrace	O
VM	B-Application
and	O
other	O
platforms	O
;	O
and	O
in	O
the	O
process	O
discontinued	O
support	O
and	O
development	O
of	O
VP/CSS	B-Application
,	O
probably	O
the	O
last	O
non-VM	O
fork	B-Application
of	O
CP/CMS	B-Application
.	O
</s>
<s>
Interactive	O
Data	O
Corporation	O
(	O
IDC	O
)	O
followed	O
a	O
plan	O
similar	O
to	O
that	O
of	O
National	O
CSS	O
,	O
selling	O
time-sharing	B-General_Concept
services	O
based	O
on	O
the	O
CP/CMS	B-Application
platform	O
.	O
</s>
<s>
Varian	O
reports	O
that	O
IDC	O
had	O
"	O
several	O
"	O
S/360	B-Device
-67	I-Device
systems	O
running	O
CP/CMS	B-Application
and	O
one	O
of	O
IBM	O
's	O
"	O
first	O
relocating	O
S/370	B-Device
"	O
,	O
presumably	O
referring	O
to	O
the	O
S/370	B-Device
-145	O
of	O
1971	O
,	O
with	O
the	O
first	O
DAT	O
box	O
;	O
but	O
perhaps	O
to	O
the	O
systems	O
announced	O
in	O
1972	O
with	O
the	O
"	O
System/370	B-Device
Advanced	O
Function	O
"	O
announcement	O
,	O
including	O
the	O
S/370	B-Device
-158	O
and	O
-168.Varian	O
,	O
op	O
.	O
</s>
<s>
[	O
Further	O
details	O
and	O
citations	O
are	O
sought	O
on	O
the	O
history	O
of	O
IDC	O
and	O
CP/CMS	B-Application
time-sharing.	O
]	O
</s>
<s>
The	O
following	O
notes	O
provide	O
brief	O
quotes	O
,	O
primarily	O
from	O
Pugh	O
and	O
Varian	O
[	O
see	O
references ]	O
,	O
illustrating	O
the	O
development	O
context	O
of	O
CP/CMS	B-Application
.	O
</s>
<s>
Early	O
time-sharing	B-General_Concept
and	O
CTSS	B-Operating_System
:	O
Christopher	O
Strachey	O
filed	O
a	O
patent	O
application	O
for	O
"	O
time-sharing	B-General_Concept
"	O
in	O
February	O
1959	O
.	O
</s>
<s>
He	O
gave	O
a	O
paper	O
"	O
Time	B-General_Concept
Sharing	I-General_Concept
in	O
Large	O
Fast	O
Computers	O
"	O
at	O
the	O
first	O
UNESCO	O
Information	O
Processing	O
Conference	O
in	O
Paris	O
in	O
June	O
that	O
year	O
,	O
where	O
he	O
passed	O
the	O
concept	O
on	O
to	O
J	O
.	O
C	O
.	O
R	O
.	O
Licklider.C.	O
</s>
<s>
Strachey	O
,	O
"	O
Time	B-General_Concept
Sharing	I-General_Concept
in	O
Large	O
Fast	O
Computers	O
,	O
"	O
Proceedings	O
of	O
the	O
International	O
Conference	O
on	O
Information	O
Processing	O
,	O
Paper	O
B.2.19	O
,	O
UNESCO	O
,	O
New	O
York	O
,	O
June	O
,	O
1959	O
[	O
cited	O
in	O
Varian	O
,	O
op	O
.	O
</s>
<s>
CTSS	B-Operating_System
was	O
the	O
seminal	O
system	O
that	O
"	O
taught	O
the	O
world	O
how	O
to	O
do	O
time-sharing.	O
"	O
</s>
<s>
MIT	O
developers	O
asked	O
for	O
and	O
received	O
considerable	O
assistance	O
from	O
IBM	O
in	O
making	O
hardware	O
modifications	O
to	O
facilitate	O
CTSS	B-Operating_System
processing.Varian	O
,	O
op	O
.	O
</s>
<s>
Korn	O
,	O
The	O
Compatible	B-Operating_System
Time-Sharing	I-Operating_System
System	I-Operating_System
:	O
A	O
Programmer	O
’s	O
Guide	O
,	O
The	O
MIT	O
Press	O
,	O
Cambridge	O
,	O
MA	O
,	O
1963	O
[	O
cited	O
in	O
Varian	O
,	O
op	O
.	O
</s>
<s>
Creasy	O
describes	O
the	O
important	O
influence	O
of	O
CTSS	B-Operating_System
on	O
CP/CMS	B-Application
:	O
"	O
CTSS	B-Operating_System
…	O
most	O
strongly	O
influenced	O
the	O
CP/CMS	B-Application
system	O
design.	O
…	O
 [ It ] 	O
provided	O
a	O
subset	O
of	O
the	O
machine	O
for	O
use	O
by	O
normal	O
batch	B-General_Concept
programs	I-General_Concept
…	O
run	O
without	O
modification	O
as	O
with	O
a	O
normal	O
system	O
.	O
</s>
<s>
The	O
time-sharing	B-General_Concept
supervisor	O
would	O
steal	O
and	O
restore	O
the	O
machine	O
without	O
their	O
knowledge	O
.	O
</s>
<s>
This	O
technique	O
was	O
extended	O
to	O
its	O
fullest	O
in	O
CP/CMS	B-Application
.	O
</s>
<s>
Many	O
other	O
CTSS	B-Operating_System
design	O
elements	O
and	O
system	O
facilities	O
,	O
like	O
the	O
user	O
interface	O
,	O
terminal	O
control	O
,	O
disk	O
file	O
system	O
,	O
and	O
attachment	O
of	O
other	O
computers	O
,	O
served	O
as	O
operational	O
prototypes.	O
…	O
The	O
necessity	O
of	O
compatibility	O
for	O
evolutionary	O
growth	O
of	O
software	O
was	O
demonstrated	O
by	O
CTSS	B-Operating_System
;	O
for	O
hardware	O
,	O
by	O
the	O
IBM	B-Application
System/360	I-Application
family	O
.	O
</s>
<s>
485	O
–	O
87	O
—	O
influence	O
of	O
CTSS	B-Operating_System
.	O
</s>
<s>
Role	O
of	O
John	O
McCarthy	O
(	O
of	O
LISP	B-Language
fame	O
)	O
in	O
timesharing	B-General_Concept
:	O
"	O
At	O
about	O
this	O
time	O
[	O
April	O
1961 ]	O
John	O
McCarthy	O
…	O
gave	O
a	O
special	O
evening	O
lecture	O
[	O
stressing	O
the	O
future	O
importance	O
of	O
time-sharing	B-General_Concept
that ]	O
ended	O
on	O
the	O
speculative	O
note	O
that	O
computation	O
might	O
eventually	O
'	O
be	O
organized	O
as	O
a	O
public	O
utility	O
,	O
just	O
as	O
the	O
telephone	O
system	O
is	O
a	O
public	O
utility.	O
'	O
</s>
<s>
Project	O
MAC	O
and	O
MULTICS	B-Application
:	O
MIT	O
's	O
Project	O
MAC	O
was	O
launched	O
in	O
1963	O
to	O
build	O
a	O
new	O
time-sharing	B-General_Concept
system	I-General_Concept
following	O
in	O
the	O
footsteps	O
of	O
CTSS	B-Operating_System
.	O
</s>
<s>
IBM	O
submitted	O
a	O
bid	O
to	O
provide	O
a	O
modified	O
S/360	B-Application
with	O
address	O
translation	O
(	O
the	O
"	O
Blaauw	O
Box	O
"	O
)	O
,	O
which	O
was	O
also	O
bid	O
to	O
Bell	O
Labs	O
around	O
the	O
same	O
time	O
.	O
</s>
<s>
MULTICS	B-Application
and	O
UNIX	B-Application
(	O
plus	O
various	O
other	O
minicomputer	O
platforms	O
)	O
became	O
the	O
de	O
facto	O
research	O
systems.Varian	O
,	O
op	O
.	O
</s>
<s>
MIT	O
input	O
to	O
S/360	B-Application
:	O
IBM	O
personnel	O
with	O
close	O
ties	O
to	O
MIT	O
became	O
"	O
strong	O
proponents	O
of	O
time-sharing	B-General_Concept
"	O
and	O
kept	O
System/360	B-Application
designers	O
aware	O
of	O
work	O
at	O
MIT	O
,	O
including	O
the	O
purpose	O
of	O
the	O
CTSS	B-Operating_System
hardware	O
enhancements	O
.	O
</s>
<s>
System/360	B-Application
architects	O
visited	O
MIT	O
and	O
talked	O
with	O
Professor	O
Corbató	O
.	O
</s>
<s>
Nevertheless	O
,	O
the	O
IBM	O
belief	O
was	O
now	O
that	O
"	O
time-sharing	B-General_Concept
would	O
never	O
amount	O
to	O
anything	O
and	O
that	O
what	O
the	O
world	O
needed	O
was	O
faster	O
batch	O
processing.	O
"	O
</s>
<s>
When	O
the	O
System/360	B-Application
was	O
announced	O
in	O
1964	O
without	O
address	O
relocation	O
,	O
MIT	O
and	O
other	O
time-sharing	B-General_Concept
advocates	O
felt	O
betrayed.Varian	O
,	O
op	O
.	O
</s>
<s>
Virtual	B-Architecture
memory	I-Architecture
and	O
timesharing	B-General_Concept
:	O
"	O
In	O
June	O
[	O
1964 ]	O
...	O
[	O
MIT	O
was ]	O
adamant	O
that	O
hardware-aided	O
dynamic	O
address	O
translation	O
(	O
DAT	O
)	O
was	O
essential	O
"	O
for	O
time-sharing	B-General_Concept
,	O
a	O
"	O
still-experimental	O
mode	O
of	O
operation	O
whereby	O
users	O
at	O
several	O
consoles	O
could	O
share	O
the	O
facilities	O
of	O
a	O
computer	O
....	O
</s>
<s>
MIT	O
would	O
n't	O
back	O
down	O
on	O
this	O
position	O
,	O
felt	O
betrayed	O
by	O
IBM	O
,	O
and	O
ultimiately	O
turned	O
away	O
from	O
IBM	O
to	O
GE	O
for	O
a	O
MULTICS	B-Application
platform.Pugh	O
et	O
al.	O
,	O
op	O
.	O
</s>
<s>
Cambridge	O
Scientific	O
Center	O
(	O
CSC	O
)	O
:	O
Established	O
in	O
1964	O
by	O
Norm	O
Rasmussen	O
,	O
in	O
the	O
same	O
building	O
with	O
Project	O
MAC	O
(	O
a	O
location	O
with	O
"	O
ten	O
or	O
fifteen	O
time-sharing	B-General_Concept
systems	I-General_Concept
being	O
coded	O
or	O
tested	O
or	O
accessed	O
"	O
in	O
the	O
mid	O
60s	O
)	O
,	O
CSC	O
developed	O
and	O
maintained	O
close	O
ties	O
with	O
MIT	O
researchers	O
.	O
</s>
<s>
This	O
was	O
the	O
environment	O
where	O
CP-40	B-Application
came	O
to	O
life.Varian	O
,	O
op	O
.	O
</s>
<s>
timesharing	B-General_Concept
,	O
championed	O
by	O
MIT	O
researchers	O
working	O
closely	O
with	O
IBM	O
)	O
.	O
</s>
<s>
Divided	O
opinion	O
about	O
the	O
S/360	B-Application
:	O
CSC	O
staff	O
became	O
champions	O
of	O
the	O
System/360	B-Application
architecture	O
,	O
in	O
the	O
face	O
of	O
deep	O
skepticism	O
in	O
the	O
scientific	O
community	O
.	O
</s>
<s>
Creasy	O
notes	O
:	O
"	O
The	O
family	O
concept	O
of	O
the	O
IBM	B-Application
System/360	I-Application
…	O
was	O
a	O
most	O
amazing	O
turning	O
point	O
in	O
computer	O
development	O
,	O
one	O
which	O
was	O
not	O
universally	O
greeted	O
with	O
enthusiasm	O
.	O
</s>
<s>
We	O
believed	O
[	O
at	O
CSC ]	O
that	O
the	O
architecture	O
of	O
System/360	B-Application
,	O
combining	O
scientific	O
and	O
commercial	O
instruction	O
sets	O
,	O
would	O
be	O
around	O
for	O
a	O
significant	O
period	O
of	O
time	O
.	O
</s>
<s>
 [ Eliminating ] 	O
the	O
trauma	O
associated	O
with	O
widespread	O
recoding	O
of	O
programs	O
[	O
via	O
the	O
S/360	B-Application
promise	O
of	O
backward	O
compatibility ]	O
also	O
pointed	O
to	O
a	O
long	O
life	O
.	O
</s>
<s>
In	O
addition	O
,	O
we	O
speculated	O
that	O
many	O
operating	B-General_Concept
systems	I-General_Concept
and	O
a	O
large	O
number	O
of	O
application	O
programs	O
would	O
be	O
produced	O
over	O
the	O
lifetime	O
of	O
that	O
machine	O
design	O
.	O
</s>
<s>
cit.	O
,	O
p	O
.	O
486	O
—	O
CSC	O
view	O
of	O
S/360	B-Application
These	O
proved	O
to	O
be	O
good	O
predictions	O
.	O
</s>
<s>
IBM	O
's	O
1965	O
reorganization	O
:	O
The	O
two	O
IBM	O
product	O
divisions	O
pursuing	O
time-sharing	B-General_Concept
development	O
—	O
Advanced	O
Systems	O
Development	O
Division	O
(	O
ASDD	O
)	O
and	O
Data	O
Systems	O
Division	O
(	O
DSD	O
)	O
—	O
were	O
"	O
phased	O
out	O
;	O
their	O
…	O
resources	O
were	O
assigned	O
to	O
the	O
new	O
Systems	O
Development	O
Division	O
(	O
SDD	O
)	O
…	O
and	O
the	O
new	O
Systems	O
Manufacturing	O
Division	O
[( 	O
SMD	O
)	O
]	O
.	O
"	O
</s>
<s>
The	O
disbanding	O
of	O
large	O
organizations	O
previously	O
responsible	O
for	O
time-sharing	B-General_Concept
efforts	O
suggests	O
the	O
political	O
forces	O
at	O
work.Pugh	O
et	O
al.	O
,	O
op	O
.	O
</s>
<s>
360/67	B-Device
and	O
TSS	B-Application
:	O
Rasmussen	O
felt	O
betrayed	O
by	O
IBM	O
's	O
decision	O
to	O
ignore	O
time-sharing	B-General_Concept
,	O
and	O
he	O
decided	O
"	O
that	O
the	O
Cambridge	O
Scientific	O
Center	O
would	O
write	O
a	O
time-sharing	B-General_Concept
system	I-General_Concept
for	O
System/360.	O
"	O
</s>
<s>
Rough	O
specifications	O
were	O
prepared	O
for	O
the	O
new	O
S/360	B-Device
-67	I-Device
,	O
which	O
would	O
incorporate	O
address	O
translation	O
(	O
via	O
the	O
"	O
DAT	O
Box	O
"	O
,	O
which	O
unlike	O
the	O
"	O
Blaauw	O
Box	O
"	O
,	O
supported	O
both	O
segment	O
and	O
page	O
tables	O
)	O
and	O
a	O
new	O
operating	B-General_Concept
system	I-General_Concept
:	O
TSS	B-Application
.	O
</s>
<s>
TSS	B-Application
was	O
announced	O
in	O
August	O
1965	O
,	O
an	O
"	O
elegant	O
and	O
very	O
ambitious	O
system	O
"	O
but	O
"	O
snatched	O
from	O
its	O
nest	O
too	O
young	O
"	O
with	O
"	O
serious	O
stability	O
and	O
performance	O
problems	O
.	O
</s>
<s>
CSC	O
financial	O
resources	O
:	O
Rasmussen	O
used	O
creative	O
accounting	O
to	O
fund	O
the	O
creation	O
of	O
CP-40	B-Application
.	O
</s>
<s>
He	O
traded	O
part	O
of	O
that	O
time	O
to	O
the	O
 [ MIT ] 	O
Computation	O
Center	O
for	O
CTSS	B-Operating_System
time	O
for	O
his	O
programmers	O
to	O
use	O
in	O
doing	O
their	O
development	O
work	O
.	O
</s>
<s>
He	O
'	O
sold	O
 '	O
the	O
remainder	O
[	O
of	O
the	O
7094	O
time ]	O
to	O
IBM	O
hardware	O
developers	O
in	O
Poughkeepsie	O
,	O
who	O
badly	O
needed	O
7094	O
time	O
to	O
run	O
a	O
design	O
automation	O
program	O
that	O
was	O
critical	O
for	O
System/360	B-Application
hardware	O
development	O
.	O
</s>
<s>
Rasmussen	O
also	O
sold	O
spare	O
time	O
on	O
another	O
,	O
temporary	O
S/360	B-Application
-40	O
,	O
provided	O
by	O
IBM	O
to	O
CSC	O
while	O
they	O
waited	O
for	O
their	O
modified	O
virtual	B-Architecture
memory	I-Architecture
system	O
.	O
</s>
<s>
If	O
there	O
was	O
a	O
perception	O
at	O
MIT	O
that	O
MIT	O
funds	O
went	O
into	O
CP/CMS	B-Application
,	O
it	O
may	O
have	O
come	O
from	O
these	O
complicated	O
transactions	O
.	O
</s>
<s>
Anti-timesharing	O
decisions	O
:	O
"	O
During	O
1961	O
and	O
1962	O
time-sharing	B-General_Concept
[	O
efforts	O
had	O
involved ]	O
close	O
contact	O
with	O
the	O
MIT	O
Computation	O
Center	O
through	O
sales	O
and	O
special	O
engineering	O
personnel.	O
"	O
</s>
<s>
After	O
MIT	O
's	O
criticisms	O
,	O
and	O
their	O
ultimate	O
choice	O
of	O
GE	O
for	O
MULTICS	B-Application
,	O
an	O
IBM	O
task	O
force	O
"	O
made	O
useful	O
suggestions	O
but	O
effectively	O
endorsed	O
the	O
work	O
of	O
the	O
360	O
designers	O
by	O
reporting	O
that	O
too	O
little	O
was	O
known	O
about	O
the	O
time-sharing	B-General_Concept
mode	O
of	O
operation	O
to	O
justify	O
[	O
its	O
pursuit ]	O
.	O
…	O
In	O
1967	O
,	O
an	O
industry	O
observerJ	O
.	O
</s>
<s>
J	O
.	O
Glauthier	O
,	O
"	O
Computer	O
time	B-General_Concept
sharing	I-General_Concept
,	O
its	O
origins	O
and	O
development	O
,	O
"	O
Computers	O
and	O
automation	O
,	O
October	O
1967	O
,	O
pp	O
.	O
</s>
<s>
counted	O
about	O
forty	O
general-purpose	O
time-sharing	B-General_Concept
installations	O
in	O
the	O
United	O
States	O
–	O
up	O
from	O
ten	O
in	O
1965	O
and	O
up	O
from	O
one	O
(	O
the	O
MIT	O
demonstration	O
)	O
in	O
1961	O
.	O
</s>
<s>
Informal	O
release	O
of	O
CP/CMS	B-Application
:	O
CP-67/CMS	O
"	O
was	O
announced	O
informally	O
because	O
it	O
was	O
developed	O
outside	O
of	O
the	O
product	O
development	O
organizations	O
in	O
the	O
product	O
and	O
marketing	O
divisions	O
.	O
</s>
<s>
Relationship	O
of	O
early	O
time-sharing	B-General_Concept
to	O
introduction	O
of	O
HP-35	O
:	O
Before	O
the	O
availability	O
of	O
powerful	O
handheld	O
calculators	O
in	O
1972	O
,	O
during	O
the	O
"	O
first	O
decade	O
of	O
time-sharing	B-General_Concept
,	O
one	O
use	O
for	O
a	O
terminal	O
was	O
to	O
request	O
minor	O
calculations	O
that	O
needed	O
to	O
be	O
carried	O
to	O
more	O
decimal	O
places	O
than	O
possible	O
with	O
a	O
slide	O
rule.	O
"	O
</s>
<s>
This	O
was	O
one	O
reason	O
time-sharing	B-General_Concept
was	O
so	O
important	O
to	O
scientific	O
and	O
academic	O
users.Pugh	O
et	O
al.	O
,	O
op	O
.	O
</s>
<s>
Virtual	B-Architecture
memory	I-Architecture
,	O
and	O
IBM	O
's	O
fear	O
of	O
risk	O
:	O
"	O
In	O
the	O
aftermath	O
of	O
the	O
System/360	B-Application
trauma	O
,	O
"	O
a	O
reference	O
to	O
large-project	O
woes	O
such	O
as	O
those	O
described	O
by	O
Fred	O
Brooks	O
,	O
IBM	O
executives	O
"	O
took	O
steps	O
to	O
ensure	O
that	O
the	O
company	O
would	O
never	O
again	O
become	O
committed	O
to	O
such	O
a	O
high-risk	O
program.	O
"	O
</s>
<s>
At	O
the	O
height	O
of	O
this	O
loin-girding	O
is	O
when	O
timesharing	B-General_Concept
and	O
virtual	B-Architecture
memory	I-Architecture
were	O
shunted	O
aside	O
by	O
IBM	O
,	O
in	O
favor	O
of	O
mainstream	O
commercial	O
batch	B-General_Concept
processing	I-General_Concept
.	O
</s>
<s>
It	O
is	O
ironic	O
that	O
,	O
by	O
1970	O
–	O
71	O
,	O
other	O
forces	O
within	O
IBM	O
"	O
set	O
in	O
motion	O
an	O
effort	O
to	O
create	O
the	O
Future	O
System	O
(	O
FS	O
)	O
[	O
project	O
with ]	O
technological	O
objectives	O
at	O
least	O
as	O
risky	O
as	O
those	O
of	O
System/360.	O
…	O
Three	O
and	O
a	O
half	O
years	O
later	O
,	O
the	O
project	O
was	O
abandoned.	O
"	O
</s>
<s>
Intent	O
and	O
use	O
of	O
CP/CMS	B-Application
:	O
Creasy	O
provides	O
this	O
insight	O
:	O
"	O
CMS	O
was	O
developed	O
…	O
to	O
support	O
its	O
own	O
development	O
and	O
maintenance	O
…	O
 [ and ] 	O
maintain	O
the	O
other	O
components	O
of	O
VM/370.	O
…	O
In	O
most	O
cases	O
,	O
a	O
subset	O
of	O
features	O
was	O
selected	O
[	O
to	O
implement	O
,	O
]	O
with	O
the	O
expectation	O
of	O
future	O
work	O
.	O
</s>
<s>
We	O
expected	O
many	O
operating	B-General_Concept
systems	I-General_Concept
to	O
flourish	O
in	O
the	O
virtual	B-Architecture
machine	I-Architecture
environment	O
.	O
</s>
<s>
cit.	O
,	O
p	O
.	O
489	O
—	O
disappointed	O
expectation	O
of	O
building	O
an	O
OS	O
incubator	O
A	O
generation	O
later	O
,	O
as	O
we	O
face	O
a	O
diversity	O
of	O
platforms	O
built	O
in	O
the	O
collaborative	O
open	B-License
source	I-License
world	O
,	O
it	O
is	O
easy	O
to	O
understand	O
Creasy	O
's	O
hopes	O
for	O
CP/CMS	B-Application
as	O
a	O
development	O
incubator	O
,	O
and	O
his	O
disappointment	O
in	O
what	O
must	O
have	O
seemed	O
missed	O
opportunities	O
.	O
</s>
<s>
This	O
has	O
been	O
the	O
fate	O
of	O
many	O
research	O
systems	O
,	O
but	O
few	O
share	O
the	O
40+	O
year	O
arc	O
of	O
the	O
concepts	O
launched	O
with	O
CP-40	B-Application
.	O
</s>
<s>
Peter	O
J	O
.	O
Denning	O
,	O
"	O
Performance	O
Modeling	O
:	O
Experimental	O
Computer	O
Science	O
at	O
its	O
Best	O
"	O
,	O
Communications	O
of	O
the	O
ACM	O
,	O
President	O
's	O
Letter	O
(	O
November	O
1981	O
)	O
―	O
Cites	O
the	O
following	O
papers	O
relating	O
to	O
the	O
IBM	B-Device
M44/44X	I-Device
:	O
</s>
<s>
L	O
.	O
Belady	O
,	O
"	O
A	O
study	O
of	O
replacement	O
algorithms	O
for	O
virtual	B-Architecture
storage	I-Architecture
computers	O
,	O
"	O
IBM	O
Systems	O
Journal	O
Vol	O
.	O
</s>
<s>
PDF	B-Application
.	O
</s>
<s>
W	O
.	O
O'Neill	O
,	O
"	O
Experience	O
using	O
a	O
time	B-General_Concept
sharing	I-General_Concept
multiprogramming	O
system	O
with	O
dynamic	O
address	O
relocation	O
hardware	O
,	O
"	O
Proc	O
.	O
</s>
<s>
611	O
–	O
21	O
―	O
[	O
Describes	O
the	O
experimental	O
IBM	B-Device
M44/44X	I-Device
,	O
reports	O
performance	O
measurements	O
related	O
to	O
memory	O
and	O
paging	O
,	O
and	O
discusses	O
performance	O
impact	O
of	O
multiprogramming	O
and	O
time-sharing.	O
]	O
</s>
<s>
D	O
.	O
Sayre	O
,	O
On	O
Virtual	O
Systems	O
,	O
''	O
IBM	O
Thomas	O
J	O
.	O
Watson	O
Research	O
Center	O
(	O
April	O
15	O
,	O
1966	O
)	O
―	O
An	O
early	O
virtual	B-Architecture
machine	I-Architecture
paper	O
,	O
describing	O
multiprogramming	O
with	O
the	O
IBM	B-Device
M44/44X	I-Device
,	O
an	O
experimental	O
paging	O
system	O
.	O
</s>
