<s>
z/OS	B-Application
is	O
a	O
64-bit	B-Device
operating	B-General_Concept
system	I-General_Concept
for	O
IBM	B-Device
z/Architecture	I-Device
mainframes	O
,	O
introduced	O
by	O
IBM	O
in	O
October	O
2000	O
.	O
</s>
<s>
It	O
derives	O
from	O
and	O
is	O
the	O
successor	O
to	O
OS/390	B-Application
,	O
which	O
in	O
turn	O
was	O
preceded	O
by	O
a	O
string	O
of	O
MVS	B-Application
versions	O
.	O
</s>
<s>
Like	O
OS/390	B-Application
,	O
z/OS	B-Application
combines	O
a	O
number	O
of	O
formerly	O
separate	O
,	O
related	O
products	O
,	O
some	O
of	O
which	O
are	O
still	O
optional	O
.	O
</s>
<s>
z/OS	B-Application
has	O
the	O
attributes	O
of	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
,	O
but	O
also	O
retains	O
much	O
of	O
the	O
older	O
functionality	O
originated	O
in	O
the	O
1960s	O
and	O
still	O
in	O
regular	O
use	O
—	O
z/OS	B-Application
is	O
designed	O
for	O
backward	B-General_Concept
compatibility	I-General_Concept
.	O
</s>
<s>
z/OS	B-Application
supports	O
stable	O
mainframe	O
facilities	O
such	O
as	O
CICS	B-Application
,	O
COBOL	B-Application
,	O
IMS	B-Application
,	O
PL/I	B-Language
,	O
IBM	B-Application
Db2	I-Application
,	O
RACF	B-Application
,	O
SNA	B-Architecture
,	O
IBM	B-Application
MQ	I-Application
,	O
record-oriented	O
data	O
access	B-Application
methods	I-Application
,	O
REXX	B-Language
,	O
CLIST	B-Operating_System
,	O
SMP/E	B-Application
,	O
JCL	B-Application
,	O
TSO/E	B-Application
,	O
and	O
ISPF	B-Operating_System
,	O
among	O
others	O
.	O
</s>
<s>
However	O
,	O
z/OS	B-Application
also	O
implements	O
64-bit	B-Device
Java	B-Language
,	O
C	B-Language
,	O
C++	B-Language
,	O
and	O
UNIX	O
(	O
Single	O
UNIX	O
Specification	O
)	O
APIs	O
and	O
applications	O
through	O
UNIX	B-Operating_System
System	I-Operating_System
Services	I-Operating_System
–	O
The	B-Application
Open	I-Application
Group	I-Application
certifies	O
z/OS	B-Application
as	O
a	O
compliant	O
UNIX	O
operating	B-General_Concept
system	I-General_Concept
–	O
with	O
UNIX/Linux	O
-style	O
hierarchical	O
HFS	B-Application
and	O
zFS	B-Application
file	B-Application
systems	I-Application
.	O
</s>
<s>
These	O
compatibilities	O
make	O
z/OS	B-Application
capable	O
of	O
running	O
a	O
range	O
of	O
commercial	O
and	O
open	B-Application
source	I-Application
software	I-Application
.	O
</s>
<s>
z/OS	B-Application
can	O
communicate	O
directly	O
via	O
TCP/IP	B-Protocol
,	O
including	O
IPv6	B-Protocol
,	O
and	O
includes	O
standard	O
HTTP	B-Application
servers	I-Application
(	O
one	O
from	O
Lotus	O
,	O
the	O
other	O
Apache-derived	O
)	O
along	O
with	O
other	O
common	O
services	O
such	O
as	O
SSH	B-Protocol
,	O
FTP	B-Protocol
,	O
NFS	B-Protocol
,	O
and	O
CIFS/SMB	B-Operating_System
.	O
</s>
<s>
z/OS	B-Application
is	O
designed	O
for	O
high	O
quality	O
of	O
service	O
(	O
QoS	O
)	O
,	O
even	O
within	O
a	O
single	O
operating	B-General_Concept
system	I-General_Concept
instance	O
,	O
and	O
has	O
built-in	O
Parallel	B-Operating_System
Sysplex	I-Operating_System
clustering	O
capability	O
.	O
</s>
<s>
z/OS	B-Application
has	O
a	O
Workload	B-Application
Manager	I-Application
(	O
WLM	O
)	O
and	O
dispatcher	O
which	O
automatically	O
manages	O
numerous	O
concurrently	O
hosted	O
units	O
of	O
work	O
running	O
in	O
separate	O
key-protected	O
address	O
spaces	O
according	O
to	O
dynamically	O
adjustable	O
goals	O
.	O
</s>
<s>
This	O
capability	O
inherently	O
supports	O
multi-tenancy	O
within	O
a	O
single	O
operating	B-General_Concept
system	I-General_Concept
image	O
.	O
</s>
<s>
However	O
,	O
modern	O
IBM	B-Device
mainframes	I-Device
also	O
offer	O
two	O
additional	O
levels	O
of	O
virtualization	O
:	O
LPARs	B-Device
and	O
(	O
optionally	O
)	O
z/VM	B-Application
.	O
</s>
<s>
From	O
its	O
inception	O
z/OS	B-Application
has	O
had	O
tri-modal	O
addressing	O
(	O
24-bit	O
,	O
31-bit	O
,	O
and	O
64-bit	B-Device
)	O
.	O
</s>
<s>
Up	O
through	O
Version	O
1.5	O
,	O
z/OS	B-Application
itself	O
could	O
start	O
in	O
either	O
31-bit	O
ESA/390	O
or	O
64-bit	B-Device
z/Architecture	B-Device
mode	O
,	O
so	O
it	O
could	O
function	O
on	O
older	O
hardware	O
,	O
albeit	O
without	O
the	O
ability	O
to	O
run	O
64-bit	B-Device
applications	O
on	O
those	O
machines	O
.	O
</s>
<s>
(	O
Only	O
the	O
newer	O
z/Architecture	B-Device
hardware	O
manufactured	O
starting	O
in	O
the	O
year	O
2000	O
can	O
run	O
64-bit	B-Device
code	O
.	O
)	O
</s>
<s>
IBM	O
support	O
for	O
z/OS	B-Application
1.5	O
ended	O
on	O
March	O
31	O
,	O
2007	O
,	O
and	O
since	O
then	O
,	O
z/OS	B-Application
is	O
supported	O
only	O
on	O
z/Architecture	B-Device
mainframes	O
and	O
runs	O
only	O
in	O
64-bit	B-Device
mode	O
.	O
</s>
<s>
Application	O
programmers	O
can	O
still	O
use	O
any	O
addressing	O
mode	O
:	O
all	O
applications	O
,	O
regardless	O
of	O
their	O
addressing	O
mode(s )	O
,	O
can	O
coexist	O
without	O
modification	O
,	O
and	O
IBM	O
maintains	O
commitment	O
to	O
tri-modal	O
backward	B-General_Concept
compatibility	I-General_Concept
.	O
</s>
<s>
However	O
,	O
increasing	O
numbers	O
of	O
middleware	O
products	O
and	O
applications	O
,	O
such	O
as	O
DB2	B-Application
Version	O
8	O
and	O
above	O
,	O
now	O
require	O
and	O
exploit	O
64-bit	B-Device
addressing	O
.	O
</s>
<s>
IBM	O
markets	O
z/OS	B-Application
as	O
its	O
flagship	O
operating	B-General_Concept
system	I-General_Concept
,	O
suited	O
for	O
continuous	O
,	O
high-volume	O
operation	O
with	O
high	O
security	O
and	O
stability	O
.	O
</s>
<s>
z/OS	B-Application
is	O
available	O
under	O
standard	O
license	O
pricing	O
and	O
via	O
IBM	O
Z	O
New	O
Application	O
License	O
Charges	O
(	O
zNALC	O
)	O
and	O
"	O
IBM	O
Z	O
Solution	O
Edition	O
"	O
,	O
two	O
lower-priced	O
offerings	O
aimed	O
at	O
supporting	O
newer	O
applications	O
(	O
"	O
new	O
workloads	O
"	O
)	O
.	O
</s>
<s>
U.S.	O
standard	O
commercial	O
z/OS	B-Application
pricing	O
starts	O
at	O
about	O
US$125	O
per	O
month	O
,	O
including	O
support	O
,	O
for	O
the	O
smallest	O
zNALC	O
installation	O
running	O
the	O
base	O
z/OS	B-Application
product	O
plus	O
a	O
typical	O
set	O
of	O
optional	O
z/OS	B-Application
features	O
.	O
</s>
<s>
z/OS	B-Application
introduced	O
Variable	O
Workload	O
License	O
Charges	O
(	O
VWLC	O
)	O
and	O
Entry	O
Workload	O
License	O
Charges	O
(	O
EWLC	O
)	O
which	O
are	O
sub-capacity	O
billing	O
options	O
.	O
</s>
<s>
VWLC	O
and	O
EWLC	O
customers	O
only	O
pay	O
for	O
peak	O
monthly	O
z/OS	B-Application
usage	O
,	O
not	O
for	O
full	O
machine	O
capacity	O
as	O
with	O
the	O
previous	O
OS/390	B-Application
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
VWLC	O
and	O
EWLC	O
are	O
also	O
available	O
for	O
most	O
IBM	O
software	O
products	O
running	O
on	O
z/OS	B-Application
,	O
and	O
their	O
peaks	O
are	O
separately	O
calculated	O
but	O
can	O
never	O
exceed	O
the	O
z/OS	B-Application
peak	O
.	O
</s>
<s>
To	O
be	O
eligible	O
for	O
sub-capacity	O
licensing	O
,	O
a	O
z/OS	B-Application
customer	O
must	O
be	O
running	O
in	O
64-bit	B-Device
mode	O
(	O
which	O
requires	O
z/Architecture	B-Device
hardware	O
)	O
,	O
must	O
have	O
eliminated	O
OS/390	B-Application
from	O
the	O
system	O
,	O
and	O
must	O
e-mail	O
IBM	O
monthly	O
sub-capacity	O
reports	O
.	O
</s>
<s>
Sub-capacity	O
billing	O
substantially	O
reduces	O
software	O
charges	O
for	O
most	O
IBM	B-Device
mainframe	I-Device
customers	O
.	O
</s>
<s>
z/OS	B-Application
supports	O
64-bit	B-Device
addresses	O
for	O
both	O
virtual	O
and	O
real	O
addresses	O
.	O
</s>
<s>
Within	O
each	O
address	O
space	O
,	O
z/OS	B-Application
typically	O
permits	O
the	O
placement	O
of	O
only	O
data	O
,	O
not	O
code	O
,	O
above	O
the	O
2GB	O
"	O
bar	O
"	O
.	O
</s>
<s>
z/OS	B-Application
enforces	O
this	O
distinction	O
primarily	O
for	O
performance	O
reasons	O
.	O
</s>
<s>
IBM	O
has	O
started	O
to	O
allow	O
Java	B-Language
code	I-Language
running	O
on	O
z/OS	B-Application
to	O
execute	O
above	O
the	O
2GB	O
bar	O
,	O
again	O
for	O
performance	O
reasons	O
.	O
</s>
<s>
Starting	O
with	O
z/OS	B-Application
version	O
2	O
release	O
3	O
,	O
code	O
may	O
be	O
placed	O
and	O
executed	O
above	O
the	O
2GB	O
"	O
bar	O
"	O
.	O
</s>
<s>
However	O
,	O
very	O
few	O
z/OS	B-Application
services	O
may	O
be	O
invoked	O
from	O
above	O
the	O
"	O
bar	O
"	O
.	O
</s>
<s>
(	O
This	O
type	O
was	O
introduced	O
in	O
z/OS	B-Application
Release	O
10	O
.	O
)	O
</s>
<s>
z/OS	B-Application
Encryption	O
Readiness	O
Technology	O
(	O
zERT	O
)	O
monitors	O
,	O
records	O
,	O
and	O
reports	O
details	O
of	O
z/OS	B-Application
cryptographic	O
network	O
protection	O
.	O
</s>
<s>
It	O
is	O
a	O
feature	O
of	O
z/OS	B-Application
V2R3	O
(	O
and	O
later	O
releases	O
)	O
Communications	O
Server	O
component	O
.	O
</s>
<s>
With	O
zERT	O
,	O
the	O
TCP/IP	B-Protocol
stack	I-Protocol
acts	O
as	O
a	O
focal	O
point	O
in	O
collecting	O
and	O
reporting	O
the	O
cryptographic	O
security	O
attributes	O
of	O
IPv4	O
and	O
IPv6	B-Protocol
application	O
traffic	O
that	O
is	O
protected	O
using	O
the	O
TLS/SSL	O
,	O
SSH	B-Protocol
and	O
IPSec	O
cryptographic	O
network	O
security	O
protocols	O
.	O
</s>
<s>
The	O
collected	O
connection	O
level	O
data	O
is	O
written	O
to	O
SMF	B-Application
in	O
new	O
SMF	B-Application
119	O
subtype	O
11	O
records	O
for	O
analysis	O
.	O
</s>
<s>
In	O
certain	O
environments	O
,	O
the	O
volume	O
of	O
SMF	B-Application
119	O
subtype	O
11	O
records	O
can	O
be	O
large	O
.	O
</s>
<s>
The	O
zERT	O
aggregation	O
function	O
provides	O
an	O
alternative	O
SMF	B-Application
view	O
of	O
the	O
collected	O
security	O
session	O
data	O
.	O
</s>
<s>
This	O
alternate	O
view	O
is	O
written	O
in	O
the	O
form	O
of	O
new	O
SMF	B-Application
119	O
subtype	O
12	O
records	O
that	O
summarize	O
the	O
use	O
of	O
security	O
sessions	O
by	O
many	O
application	O
connections	O
over	O
time	O
and	O
which	O
are	O
written	O
at	O
the	O
end	O
of	O
each	O
SMF	B-Application
interval	O
.	O
</s>
<s>
This	O
alternate	O
view	O
condenses	O
the	O
volume	O
of	O
SMF	B-Application
record	O
data	O
while	O
still	O
providing	O
all	O
the	O
critical	O
security	O
information	O
.	O
</s>
<s>
z/OS	B-Application
Management	O
Facility	O
(	O
z/OSMF	O
)	O
is	O
enhanced	O
to	O
provide	O
a	O
plug-in	O
named	O
IBM	O
zERT	O
Network	O
Analyzer	O
.	O
</s>
<s>
IBM	O
zERT	O
Network	O
Analyzer	O
is	O
a	O
web-based	O
graphical	O
user	O
interface	O
that	O
z/OS	B-Application
network	O
security	O
administrators	O
can	O
use	O
to	O
analyze	O
and	O
report	O
on	O
data	O
reported	O
in	O
zERT	O
Summary	O
records	O
.	O
</s>
<s>
With	O
the	O
zERT	O
Network	O
Analyzer	O
,	O
a	O
z/OS	B-Application
network	O
security	O
administrator	O
(	O
typically	O
a	O
systems	O
programmer	O
with	O
responsibility	O
over	O
z/OS	B-Application
Communications	O
Server	O
)	O
can	O
import	O
SMF	B-Application
zERT	O
summary	O
records	O
into	O
a	O
Db2	B-Application
for	O
z/OS	B-Application
database	O
and	O
then	O
build	O
and	O
run	O
custom	O
queries	O
against	O
that	O
data	O
.	O
</s>
<s>
The	O
z/OS	B-Application
Generation	O
Data	O
Group	O
(	O
GDG	O
)	O
is	O
a	O
description	O
of	O
how	O
many	O
generations	O
of	O
a	O
file	O
are	O
to	O
be	O
kept	O
and	O
at	O
what	O
age	O
a	O
generation	O
will	O
be	O
deleted	O
.	O
</s>
<s>
The	O
purpose	O
of	O
GDGs	O
is	O
to	O
automate	O
archival	O
,	O
using	O
the	O
command	O
language	O
JCL	B-Application
,	O
the	O
file	O
name	O
given	O
is	O
generic	O
.	O
</s>
<s>
Another	O
use	O
of	O
GDGs	O
is	O
to	O
be	O
able	O
to	O
address	O
all	O
generations	O
simultaneously	O
within	O
a	O
JCL	B-Application
script	O
without	O
having	O
to	O
know	O
the	O
number	O
of	O
currently	O
available	O
generations	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
you	O
have	O
to	O
omit	O
the	O
parentheses	O
and	O
the	O
generation	O
number	O
in	O
the	O
JCL	B-Application
when	O
specifying	O
the	O
dataset	O
.	O
</s>
<s>
Operational	O
data	O
is	O
data	O
that	O
z/OS	B-Application
system	O
produces	O
when	O
it	O
runs	O
.	O
</s>
<s>
IBM	O
Z	O
Operational	O
Log	O
and	O
Data	O
Analytics	O
and	O
IBM	O
Z	O
Anomaly	O
Analytics	O
with	O
Watson	O
collect	O
IT	O
operational	O
data	O
from	O
z/OS	B-Application
systems	O
,	O
analyze	O
and	O
provide	O
insights	O
about	O
the	O
operational	O
data	O
.	O
</s>
<s>
IBM	O
Z	O
Operational	O
Log	O
and	O
Data	O
Analytics	O
collects	O
IT	O
operational	O
data	O
from	O
z/OS	B-Application
systems	O
,	O
transforms	O
it	O
to	O
a	O
consumable	O
format	O
,	O
and	O
streams	O
it	O
to	O
third-party	O
enterprise	O
analytics	O
platforms	O
like	O
the	O
Elastic	O
Stack	O
and	O
Splunk	B-General_Concept
,	O
or	O
to	O
the	O
included	O
operational	O
data	O
analysis	O
platform	O
.	O
</s>
<s>
IBM	O
Z	O
Anomaly	O
Analytics	O
with	O
Watson	O
collects	O
IT	O
operational	O
data	O
from	O
z/OS	B-Application
systems	O
,	O
uses	O
historical	O
IBM	O
Z	O
metric	O
and	O
log	O
data	O
to	O
build	O
a	O
model	O
of	O
normal	O
operational	O
behavior	O
,	O
then	O
analyzes	O
real-time	O
operational	O
data	O
through	O
comparison	O
with	O
the	O
model	O
of	O
normal	O
operations	O
to	O
detect	O
anomalous	O
behavior	O
,	O
and	O
notifies	O
IT	O
operations	O
of	O
the	O
anomalous	O
behavior	O
to	O
identify	O
incidents	O
that	O
might	O
lead	O
to	O
business	O
disruption	O
.	O
</s>
<s>
IBM	O
Z	O
Anomaly	O
Analytics	O
with	O
Watson	O
collects	O
data	O
from	O
multiple	O
IBM	O
Z	O
systems	O
and	O
subsystems	O
,	O
including	O
IBM	B-Application
Db2	I-Application
for	O
z/OS	B-Application
,	O
IBM	O
CICS	B-Application
Transaction	I-Application
Server	I-Application
for	O
z/OS	B-Application
and	O
IBM	B-Application
MQ	I-Application
for	O
z/OS	B-Application
.	O
</s>
