<s>
ACF2	B-Application
(	O
Access	B-Application
Control	I-Application
Facility	I-Application
2	O
)	O
is	O
a	O
commercial	B-Application
,	O
discretionary	O
access	O
control	O
software	O
security	O
system	O
developed	O
for	O
the	O
MVS	B-Application
(	O
z/OS	O
today	O
)	O
,	O
VSE	B-Application
(	O
z/VSE	B-Application
today	O
)	O
and	O
VM	B-Application
(	O
z/VM	O
today	O
)	O
IBM	B-Device
mainframe	I-Device
operating	B-General_Concept
systems	I-General_Concept
by	O
SKK	O
,	O
Inc	O
.	O
Barry	O
Schrager	O
,	O
Eberhard	O
Klemens	O
,	O
and	O
Scott	O
Krueger	O
combined	O
to	O
develop	O
ACF2	B-Application
at	O
London	O
Life	O
Insurance	O
in	O
London	O
,	O
Ontario	O
in	O
1978	O
.	O
</s>
<s>
The	O
"	O
2	O
"	O
was	O
added	O
to	O
the	O
ACF2	B-Application
name	O
by	O
Cambridge	O
Systems	O
(	O
who	O
had	O
the	O
North	O
American	O
marketing	O
rights	O
for	O
the	O
product	O
)	O
to	O
differentiate	O
it	O
from	O
the	O
prototype	O
,	O
which	O
was	O
developed	O
by	O
Schrager	O
and	O
Klemens	O
at	O
the	O
University	O
of	O
Illinois	O
—	O
the	O
prototype	O
name	O
was	O
ACF	O
.	O
</s>
<s>
ACF2	B-Application
was	O
developed	O
in	O
response	O
to	O
IBM	O
's	O
RACF	B-Application
product	O
(	O
developed	O
in	O
1976	O
)	O
,	O
which	O
was	O
IBM	O
's	O
answer	O
to	O
the	O
1974	O
SHARE	O
Security	O
and	O
Data	O
Management	O
project	O
's	O
requirement	O
whitepaper	O
.	O
</s>
<s>
ACF2	B-Application
's	O
design	O
was	O
guided	O
by	O
these	O
requirements	O
,	O
taking	O
a	O
resource-rule	O
oriented	O
approach	O
.	O
</s>
<s>
Unique	O
to	O
ACF2	B-Application
were	O
the	O
concepts	O
of	O
"	O
Protection	O
by	O
Default	O
"	O
and	O
resource	O
pattern	O
masking	O
.	O
</s>
<s>
As	O
a	O
result	O
of	O
the	O
competitive	O
tension	O
between	O
RACF	B-Application
and	O
ACF2	B-Application
,	O
IBM	O
matured	O
the	O
SAF	O
(	O
Security	O
Access	O
Facility	O
)	O
interface	O
in	O
MVS	B-Application
(	O
now	O
z/OS	O
)	O
,	O
which	O
allowed	O
any	O
security	O
product	O
to	O
process	O
operating	B-General_Concept
system	I-General_Concept
(	O
"	O
OS	O
"	O
)	O
,	O
third-party	O
software	O
and	O
application	O
security	O
calls	O
,	O
enabling	O
the	O
mainframe	O
to	O
secure	O
all	O
facets	O
of	O
mainframe	O
operations	O
.	O
</s>
<s>
SKK	O
and	O
ACF2	B-Application
were	O
sold	O
to	O
UCCEL	O
Corporation	O
in	O
1986	O
,	O
which	O
in	O
turn	O
was	O
purchased	O
by	O
Computer	O
Associates	O
International	O
,	O
Inc	O
.	O
in	O
1987	O
.	O
</s>
<s>
Broadcom	O
Inc	O
.	O
now	O
(	O
2019	O
)	O
markets	O
ACF2	B-Application
as	O
CA	B-Application
ACF2	I-Application
.	O
</s>
