<s>
Remote	B-Application
Spooling	I-Application
Communications	I-Application
Subsystem	I-Application
or	O
RSCS	B-Application
is	O
a	O
subsystem	O
(	O
"	O
virtual	O
machine	O
"	O
in	O
VM	B-Application
terminology	O
)	O
of	O
IBM	O
's	O
VM/370	B-Application
operating	I-Application
system	I-Application
which	O
accepts	O
files	O
transmitted	O
to	O
it	O
from	O
local	O
or	O
remote	O
system	O
and	O
users	O
and	O
transmits	O
them	O
to	O
destination	O
local	O
or	O
remote	O
users	O
and	O
systems	O
.	O
</s>
<s>
RSCS	B-Application
also	O
transmits	O
commands	O
and	O
messages	O
among	O
users	O
and	O
systems	O
.	O
</s>
<s>
RSCS	B-Application
is	O
the	O
software	O
that	O
powered	O
the	O
world	O
’s	O
largest	O
network	O
(	O
or	O
network	O
of	O
networks	O
)	O
prior	O
to	O
the	O
Internet	O
and	O
directly	O
influenced	O
both	O
internet	O
development	O
and	O
user	O
acceptance	O
of	O
networking	O
between	O
independently	O
managed	O
organizations	O
.	O
</s>
<s>
RSCS	B-Application
was	O
developed	O
by	O
Edson	O
Hendricks	O
and	O
T.C.	O
</s>
<s>
Both	O
as	O
an	O
IBM	O
product	O
and	O
as	O
an	O
IBM	O
internal	O
network	O
,	O
it	O
later	O
became	O
known	O
as	O
VNET	B-General_Concept
.	O
</s>
<s>
The	O
network	O
interfaces	O
continued	O
to	O
be	O
called	O
the	O
RSCS	B-Application
compatible	O
protocols	O
and	O
were	O
used	O
to	O
interconnect	O
with	O
IBM	O
systems	O
other	O
than	O
VM	B-Application
systems	O
(	O
typically	O
MVS	B-Application
)	O
and	O
non-IBM	O
computers	O
.	O
</s>
<s>
Among	O
academic	O
users	O
,	O
the	O
same	O
software	O
was	O
employed	O
by	O
BITNET	B-General_Concept
and	O
related	O
networks	O
worldwide	O
.	O
</s>
<s>
RSCS	B-Application
arose	O
because	O
people	O
throughout	O
IBM	O
recognized	O
a	O
need	O
to	O
exchange	O
files	O
.	O
</s>
<s>
After	O
additional	O
iterations	O
,	O
based	O
on	O
feedback	O
from	O
real	O
users	O
and	O
contributed	O
suggestions	O
and	O
code	O
from	O
around	O
the	O
company	O
,	O
Hendricks	O
and	O
Tim	O
Hartmann	O
,	O
of	O
the	O
IBM	O
Technology	O
Data	O
Center	O
in	O
Poughkeepsie	O
,	O
NY	O
,	O
produced	O
RSCS	B-Application
,	O
which	O
went	O
into	O
operation	O
within	O
IBM	O
in	O
1973	O
.	O
</s>
<s>
The	O
first	O
version	O
of	O
RSCS	B-Application
distributed	O
outside	O
of	O
IBM	O
(	O
1975	O
)	O
was	O
not	O
a	O
complete	O
networking	O
package	O
.	O
</s>
<s>
It	O
included	O
uncalled	O
subroutines	O
for	O
functions	O
such	O
as	O
store-and-forward	B-Protocol
that	O
were	O
included	O
in	O
the	O
IBM	O
internal	O
version	O
.	O
</s>
<s>
The	O
store-and-forward	B-Protocol
function	O
was	O
added	O
in	O
the	O
VNET	B-General_Concept
PRPQ	O
,	O
first	O
for	O
files	O
,	O
and	O
then	O
for	O
messages	O
and	O
commands	O
.	O
</s>
<s>
At	O
SHARE	O
XLVI	O
,	O
in	O
February	O
,	O
1976	O
,	O
Hendricks	O
and	O
Hartmann	O
reported	O
that	O
the	O
network	O
,	O
which	O
was	O
now	O
beginning	O
to	O
be	O
called	O
VNET	B-General_Concept
,	O
spanned	O
the	O
continent	O
and	O
connected	O
50	O
systems	O
.	O
</s>
<s>
By	O
SHARE	O
52	O
,	O
in	O
March	O
,	O
1979	O
,	O
they	O
reported	O
that	O
VNET	B-General_Concept
connected	O
239	O
systems	O
,	O
in	O
38	O
U.S.	O
cities	O
and	O
10	O
other	O
countries	O
.	O
</s>
<s>
“	O
VNET	B-General_Concept
passed	O
1000	O
nodes	O
in	O
1983	O
and	O
3000	O
nodes	O
in	O
1989	O
.	O
</s>
<s>
Both	O
ARPANET	O
and	O
VNET	B-General_Concept
continued	O
to	O
grow	O
rapidly	O
.	O
</s>
<s>
By	O
1986	O
,	O
IBM	O
’s	O
Think	O
magazine	O
estimated	O
that	O
VNET	B-General_Concept
was	O
saving	O
the	O
company	O
$	O
150,000,000	O
per	O
year	O
as	O
the	O
result	O
of	O
increased	O
productivity	O
.	O
</s>
<s>
Due	O
to	O
the	O
key	O
role	O
RSCS	B-Application
played	O
in	O
building	O
networks	O
,	O
the	O
line	O
drivers	O
became	O
known	O
as	O
the	O
"	O
RSCS	B-Application
Protocols	O
"	O
.	O
</s>
<s>
To	O
expand	O
the	O
RSCS	B-Application
network	O
to	O
include	O
MVS	B-Application
,	O
Hartmann	O
reverse-engineered	O
the	O
HASP	B-Application
Network	O
Job	O
Interface	O
protocol	O
,	O
which	O
enabled	O
the	O
network	O
to	O
grow	O
rapidly	O
.	O
</s>
<s>
He	O
later	O
added	O
the	O
JES2	O
Network	O
Job	O
Entry	O
as	O
an	O
RSCS/VNET	O
line	O
driver	O
.	O
</s>
<s>
BITNET	B-General_Concept
was	O
a	O
cooperative	O
United	O
States	O
university	O
network	O
founded	O
in	O
1981	O
by	O
Ira	O
Fuchs	O
at	O
the	O
City	O
University	O
of	O
New	O
York	O
(	O
CUNY	O
)	O
and	O
Greydon	O
Freeman	O
at	O
Yale	O
University	O
which	O
was	O
based	O
on	O
VNET	B-General_Concept
.	O
</s>
<s>
The	O
BITNET	B-General_Concept
(	O
RSCS	B-Application
)	O
protocols	O
were	O
eventually	O
ported	O
to	O
non-IBM	O
computer	O
systems	O
,	O
and	O
became	O
widely	O
implemented	O
under	O
VAX/VMS	B-Operating_System
in	O
addition	O
to	O
DECnet	O
(	O
The	O
VAX/VMS	B-Operating_System
NJE	O
protocol	O
stack	O
was	O
known	O
as	O
Jnet	O
)	O
.	O
</s>
<s>
At	O
its	O
zenith	O
around	O
1991	O
,	O
BITNET	B-General_Concept
extended	O
to	O
almost	O
500	O
organizations	O
and	O
3,000	O
nodes	O
,	O
all	O
educational	O
institutions	O
.	O
</s>
<s>
BITNET	B-General_Concept
was	O
also	O
very	O
popular	O
in	O
other	O
parts	O
of	O
the	O
world	O
,	O
especially	O
in	O
South	O
America	O
,	O
where	O
about	O
200	O
nodes	O
were	O
implemented	O
and	O
heavily	O
used	O
in	O
the	O
late	O
1980s	O
and	O
early	O
1990s	O
.	O
</s>
<s>
Over	O
time	O
,	O
BITNET	B-General_Concept
was	O
eventually	O
merged	O
into	O
the	O
Internet	O
.	O
</s>
<s>
Newer	O
versions	O
of	O
RSCS	B-Application
,	O
as	O
well	O
as	O
Jnet	O
and	O
the	O
various	O
UNIX	O
NJE	O
stacks	O
,	O
provided	O
support	O
for	O
TCPNJE	O
line	O
drivers	O
.	O
</s>
<s>
Since	O
most	O
sites	O
that	O
were	O
on	O
BITNET	B-General_Concept
also	O
had	O
access	O
to	O
the	O
Internet	O
,	O
the	O
BITNET	B-General_Concept
links	O
that	O
were	O
once	O
ran	O
over	O
leased	O
lines	O
and	O
dialup	O
modems	O
were	O
tunneled	O
over	O
the	O
Internet	O
.	O
</s>
<s>
It	O
was	O
also	O
not	O
uncommon	O
to	O
run	O
NJE	O
over	O
SNA	B-Architecture
.	O
</s>
<s>
R	O
.	O
J	O
.	O
Creasy	O
described	O
RSCS	B-Application
as	O
an	O
operating	O
system	O
and	O
considered	O
it	O
an	O
essential	O
component	O
of	O
the	O
VM/370	B-Application
Time-Sharing	O
System	O
.	O
</s>
<s>
"	O
The	O
Virtual	O
Machine	O
Facility/370	O
,	O
VM/370	B-Application
for	O
short	O
,	O
is	O
a	O
convenient	O
name	O
for	O
three	O
different	O
operating	O
systems	O
:	O
the	O
Control	O
Program	O
(	O
CP	O
)	O
,	O
the	O
Conversational	O
Monitor	O
System	O
(	O
CMS	O
)	O
,	O
and	O
the	O
Remote	O
Spooling	O
and	O
Communications	O
Subsystem	O
(	O
RSCS	B-Application
)	O
.	O
</s>
<s>
RSCS	B-Application
...	O
is	O
the	O
operating	O
system	O
used	O
to	O
provide	O
information	O
transfer	O
among	O
machines	O
linked	O
with	O
communications	O
facilities.	O
"	O
</s>
<s>
Details	O
of	O
the	O
design	O
of	O
RSCS	B-Application
as	O
a	O
virtual	O
machine	O
subsystem	O
are	O
described	O
in	O
the	O
IBM	O
Systems	O
Journal	O
.	O
</s>
<s>
From	O
a	O
technical	O
point	O
of	O
view	O
,	O
RSCS	B-Application
differed	O
from	O
ARPANET	O
in	O
that	O
it	O
was	O
a	O
point-to-point	O
"	O
store	B-Protocol
and	I-Protocol
forward	I-Protocol
"	O
network	O
,	O
as	O
such	O
it	O
was	O
more	O
like	O
UUCP	B-Protocol
.	O
</s>
<s>
Unlike	O
ARPANET	O
,	O
it	O
did	O
not	O
require	O
dedicated	O
Interface	B-Protocol
Message	I-Protocol
Processor	I-Protocol
or	O
continuous	O
network	O
connections	O
.	O
</s>
<s>
In	O
case	O
of	O
a	O
broken	O
network	O
connection	O
RSCS	B-Application
would	O
retain	O
the	O
message	O
and	O
retry	O
transmission	O
when	O
the	O
remote	O
system	O
became	O
available	O
.	O
</s>
<s>
VNET	B-General_Concept
was	O
the	O
first	O
large-scale	O
connectionless	O
network	O
,	O
making	O
it	O
possible	O
for	O
a	O
computer	O
to	O
join	O
the	O
network	O
using	O
dial-up	O
lines	O
,	O
making	O
connection	O
inexpensive	O
while	O
ARPANET	O
required	O
dedicated	O
50kb	O
lines	O
at	O
first	O
(	O
later	O
raised	O
to	O
230KB	O
.	O
</s>
<s>
VNET	B-General_Concept
employed	O
a	O
vastly	O
simplified	O
routing	O
and	O
path	O
finding	O
approach	O
,	O
later	O
adopted	O
for	O
the	O
Internet	O
.	O
</s>
<s>
VNET	B-General_Concept
was	O
a	O
true	O
"	O
distributed	O
control	O
"	O
while	O
ARPANET	O
required	O
a	O
"	O
control	O
"	O
center	O
operated	O
at	O
Bolt	O
,	O
Beranek	O
,	O
and	O
Newman	O
in	O
Cambridge	O
,	O
MA	O
.	O
</s>
