<s>
Model	B-Application
204	I-Application
(	O
M204	O
)	O
is	O
a	O
database	B-Application
management	I-Application
system	I-Application
for	O
IBM	B-Device
and	I-Device
compatible	I-Device
mainframe	I-Device
computers	I-Device
developed	O
and	O
commercialized	O
by	O
Computer	O
Corporation	O
of	O
America	O
.	O
</s>
<s>
Implemented	O
in	O
assembly	B-Language
language	I-Language
for	O
IBM	B-Application
System/360	I-Application
and	O
its	O
successors	O
,	O
M204	O
can	O
deal	O
with	O
very	B-General_Concept
large	I-General_Concept
databases	I-General_Concept
and	O
transaction	O
loads	O
of	O
1000	O
TPS	B-General_Concept
.	O
</s>
<s>
Model	B-Application
204	I-Application
relies	O
on	O
its	O
own	O
type	O
of	O
bitmap	B-Data_Structure
index	I-Data_Structure
,	O
originally	O
devised	O
by	O
Bill	O
Mann	O
,	O
and	O
combines	O
the	O
use	O
of	O
hash	B-Algorithm
table	I-Algorithm
,	O
B-tree	B-Architecture
,	O
and	O
partitioned	O
record	O
list	O
technologies	O
to	O
optimize	O
speed	O
and	O
efficiency	O
of	O
database	O
access	O
.	O
</s>
<s>
systems ]	O
...	O
the	O
other	O
two	O
being	O
"	O
ADABAS	B-Application
and	O
ADR	O
's	O
Datacom/DB	B-Application
.	O
</s>
<s>
Although	O
M204	O
is	O
a	O
pre-SQL	O
(	O
and	O
pre-relational	O
)	O
database	O
product	O
,	O
it	O
is	O
possible	O
to	O
manually	O
map	O
the	O
files	O
of	O
an	O
M204	O
database	O
to	O
approximate	O
SQL	B-Language
equivalents	O
and	O
provide	O
some	O
limited	O
SQL	B-Language
functionality	O
using	O
Model	B-Application
204	I-Application
SQL	B-Language
Server	O
.	O
</s>
<s>
Model	B-Application
204	I-Application
is	O
commonly	O
used	O
in	O
government	O
and	O
military	O
applications	O
.	O
</s>
<s>
An	O
informal	O
list	O
of	O
past	O
and	O
present	O
Model	B-Application
204	I-Application
users	O
,	O
compiled	O
in	O
2010	O
,	O
identified	O
more	O
than	O
140	O
organizations	O
worldwide	O
.	O
</s>
<s>
Model	B-Application
204	I-Application
has	O
been	O
a	O
central	O
part	O
of	O
Australian	O
social	O
security	O
for	O
decades	O
.	O
</s>
<s>
Add-on	O
products	O
for	O
Model	B-Application
204	I-Application
database	O
were	O
formerly	O
available	O
from	O
Sirius	O
Software	O
,	O
Inc	O
.	O
</s>
