<s>
CMS	B-Operating_System
Pipelines	I-Operating_System
is	O
a	O
feature	O
of	O
the	O
VM/CMS	B-Application
operating	O
system	O
that	O
allows	O
users	O
to	O
create	O
and	O
use	O
a	O
pipeline	B-Operating_System
.	O
</s>
<s>
The	O
programs	O
in	O
a	O
pipeline	B-Operating_System
operate	O
on	O
a	O
sequential	O
stream	O
of	O
records	O
.	O
</s>
<s>
A	O
program	O
writes	O
records	O
that	O
are	O
read	O
by	O
the	O
next	O
program	O
in	O
the	O
pipeline	B-Operating_System
.	O
</s>
<s>
CMS	B-Operating_System
Pipelines	I-Operating_System
provides	O
a	O
CMS	O
command	O
,	O
PIPE	O
.	O
</s>
<s>
The	O
argument	O
string	O
to	O
the	O
PIPE	O
command	O
is	O
the	O
pipeline	B-Operating_System
specification	O
.	O
</s>
<s>
PIPE	O
selects	O
programs	O
to	O
run	O
and	O
chains	O
them	O
together	O
in	O
a	O
pipeline	B-Operating_System
to	O
pump	O
data	O
through	O
.	O
</s>
<s>
Because	O
CMS	O
programs	O
and	O
utilities	O
do	O
n't	O
provide	O
a	O
device	O
independent	O
stdin	O
and	O
stdout	O
interface	O
,	O
CMS	B-Operating_System
Pipelines	I-Operating_System
has	O
a	O
built-in	O
library	O
of	O
programs	O
that	O
can	O
be	O
called	O
in	O
a	O
pipeline	B-Operating_System
specification	O
.	O
</s>
<s>
In	O
CMS	B-Operating_System
Pipelines	I-Operating_System
the	O
data	O
is	O
passed	O
between	O
the	O
stages	O
as	O
logical	O
records	O
.	O
</s>
<s>
CMS	B-Operating_System
Pipelines	I-Operating_System
users	O
issue	O
pipeline	B-Operating_System
commands	O
from	O
the	O
terminal	O
or	O
in	O
EXEC	O
procedures	O
.	O
</s>
<s>
Users	O
can	O
write	O
programs	O
in	O
REXX	B-Language
that	O
can	O
be	O
used	O
in	O
addition	O
to	O
the	O
built-in	O
programs	O
.	O
</s>
<s>
In	O
this	O
example	O
,	O
the	O
<	O
stage	O
reads	O
the	O
input	O
disk	O
file	O
and	O
passes	O
the	O
records	O
to	O
the	O
next	O
stage	O
in	O
the	O
pipeline	B-Operating_System
.	O
</s>
<s>
The	O
pipeline	B-Operating_System
topology	O
in	O
this	O
example	O
consists	O
of	O
two	O
connected	O
pipelines	B-Operating_System
.	O
</s>
<s>
in	O
this	O
example	O
)	O
separates	O
the	O
individual	O
pipelines	B-Operating_System
in	O
the	O
pipeline	B-Operating_System
set	O
.	O
</s>
<s>
Records	O
read	O
from	O
the	O
input	O
file	O
pass	O
through	O
either	O
of	O
the	O
two	O
routes	O
of	O
the	O
pipeline	B-Operating_System
topology	O
.	O
</s>
<s>
Because	O
neither	O
of	O
the	O
routes	O
contain	O
stages	O
that	O
need	O
to	O
buffer	O
records	O
,	O
CMS	B-Operating_System
Pipelines	I-Operating_System
ensures	O
that	O
records	O
arrive	O
at	O
faninany	O
in	O
the	O
order	O
in	O
which	O
they	O
passed	O
through	O
locate	O
.	O
</s>
<s>
The	O
example	O
pipeline	B-Operating_System
is	O
presented	O
in	O
'	O
portrait	O
form	O
 '	O
with	O
the	O
individual	O
stages	O
on	O
separate	O
lines	O
.	O
</s>
<s>
When	O
a	O
pipeline	B-Operating_System
is	O
typed	O
as	O
a	O
CMS	O
command	O
,	O
all	O
stages	O
are	O
written	O
on	O
a	O
single	O
line	O
.	O
</s>
<s>
The	O
concept	O
of	O
a	O
simple	O
pipeline	B-Operating_System
is	O
extended	O
in	O
these	O
ways	O
:	O
</s>
<s>
A	O
program	O
can	O
define	O
a	O
subroutine	O
pipeline	B-Operating_System
to	O
perform	O
a	O
function	O
on	O
all	O
or	O
part	O
of	O
its	O
input	O
data	O
.	O
</s>
<s>
A	O
network	O
of	O
intersecting	O
pipelines	B-Operating_System
can	O
be	O
defined	O
.	O
</s>
<s>
Programs	O
can	O
be	O
in	O
several	O
pipelines	B-Operating_System
concurrently	O
,	O
which	O
gives	O
the	O
program	O
access	O
to	O
multiple	O
data	O
streams	O
.	O
</s>
<s>
This	O
lock-step	O
approach	O
not	O
only	O
avoids	O
copying	O
the	O
data	O
from	O
one	O
buffer	O
to	O
the	O
next	O
;	O
it	O
also	O
makes	O
it	O
possible	O
to	O
predict	O
the	O
flow	O
of	O
records	O
in	O
multi-stream	O
pipelines	B-Operating_System
.	O
</s>
<s>
A	O
program	O
can	O
dynamically	O
redefine	O
the	O
pipeline	B-Operating_System
topology	O
.	O
</s>
<s>
It	O
can	O
replace	O
itself	O
with	O
another	O
pipeline	B-Operating_System
,	O
it	O
can	O
insert	O
a	O
pipeline	B-Operating_System
segment	O
before	O
or	O
after	O
itself	O
,	O
or	O
both	O
.	O
</s>
<s>
A	O
program	O
can	O
use	O
data	O
in	O
the	O
pipeline	B-Operating_System
to	O
build	O
pipeline	B-Operating_System
specifications	O
.	O
</s>
<s>
CMS	B-Operating_System
Pipelines	I-Operating_System
offers	O
several	O
features	O
to	O
improve	O
the	O
robustness	O
of	O
programs	O
:	O
</s>
<s>
A	O
syntax	O
error	O
in	O
the	O
overall	O
pipeline	B-Operating_System
structure	O
or	O
in	O
any	O
one	O
program	O
causes	O
the	O
entire	O
pipeline	B-Operating_System
to	O
be	O
suppressed	O
.	O
</s>
<s>
Startup	O
of	O
the	O
programs	O
in	O
the	O
pipeline	B-Operating_System
and	O
allocation	O
of	O
resources	O
is	O
coordinated	O
by	O
the	O
CMS	B-Operating_System
Pipelines	I-Operating_System
dispatcher	O
.	O
</s>
<s>
Individual	O
programs	O
can	O
participate	O
in	O
that	O
coordination	O
to	O
ensure	O
irreversible	O
actions	O
are	O
postponed	O
to	O
a	O
point	O
where	O
all	O
programs	O
in	O
the	O
pipelines	B-Operating_System
have	O
had	O
a	O
chance	O
to	O
verify	O
the	O
arguments	O
and	O
are	O
ready	O
to	O
process	O
data	O
.	O
</s>
<s>
When	O
the	O
pipeline	B-Operating_System
is	O
terminated	O
,	O
the	O
dispatcher	O
ensures	O
resources	O
are	O
released	O
again	O
.	O
</s>
<s>
Errors	O
that	O
occur	O
while	O
data	O
flow	O
in	O
the	O
pipeline	B-Operating_System
can	O
be	O
detected	O
by	O
all	O
participating	O
programs	O
.	O
</s>
<s>
John	O
Hartmann	O
,	O
of	O
IBM	O
Denmark	O
,	O
started	O
development	O
of	O
CMS	B-Operating_System
Pipelines	I-Operating_System
in	O
1980	O
.	O
</s>
<s>
The	O
product	O
was	O
marketed	O
by	O
IBM	O
as	O
a	O
separate	O
product	O
during	O
the	O
80	O
's	O
and	O
integrated	O
in	O
VM/ESA	B-Application
late	O
1991	O
.	O
</s>
<s>
With	O
each	O
release	O
of	O
VM	B-Application
,	O
the	O
CMS	B-Operating_System
Pipelines	I-Operating_System
code	O
was	O
upgraded	O
as	O
well	O
until	O
it	O
was	O
functionally	O
frozen	O
at	O
the	O
1.1.10	O
level	O
in	O
VM/ESA	B-Application
2.3	O
in	O
1997	O
.	O
</s>
<s>
Since	O
then	O
,	O
the	O
latest	O
level	O
of	O
CMS	B-Operating_System
Pipelines	I-Operating_System
has	O
been	O
available	O
for	O
download	O
from	O
the	O
for	O
users	O
who	O
wish	O
to	O
explore	O
new	O
function	O
.	O
</s>
<s>
The	O
current	O
level	O
of	O
CMS	B-Operating_System
Pipelines	I-Operating_System
is	O
included	O
in	O
the	O
z/VM	B-Application
releases	O
again	O
since	O
z/VM	B-Application
6.4	O
,	O
available	O
since	O
November	O
11	O
,	O
2016	O
.	O
</s>
<s>
An	O
implementation	O
of	O
CMS	B-Operating_System
Pipelines	I-Operating_System
for	O
TSO	B-Application
was	O
released	O
in	O
1995	O
as	O
BatchPipeWorks	O
in	O
the	O
BatchPipes/MVS	B-Application
product	O
.	O
</s>
<s>
The	O
up-to-date	O
TSO	B-Application
implementation	O
has	O
been	O
available	O
as	O
a	O
Service	O
Offering	O
from	O
IBM	O
Denmark	O
until	O
2010	O
.	O
</s>
<s>
Both	O
versions	O
are	O
maintained	O
from	O
a	O
single	O
source	O
code	O
base	O
and	O
commonly	O
referred	O
to	O
as	O
CMS/TSO	O
Pipelines	B-Operating_System
.	O
</s>
