<s>
Architecture	B-Architecture
description	I-Architecture
languages	I-Architecture
(	O
ADLs	O
)	O
are	O
used	O
in	O
several	O
disciplines	O
:	O
system	O
engineering	O
,	O
software	B-General_Concept
engineering	I-General_Concept
,	O
and	O
enterprise	O
modelling	O
and	O
engineering	O
.	O
</s>
<s>
The	O
system	O
engineering	O
community	O
uses	O
an	O
architecture	B-Architecture
description	I-Architecture
language	I-Architecture
as	O
a	O
language	O
and/or	O
a	O
conceptual	B-Application
model	I-Application
to	O
describe	O
and	O
represent	O
system	B-Architecture
architectures	I-Architecture
.	O
</s>
<s>
The	O
software	B-General_Concept
engineering	I-General_Concept
community	O
uses	O
an	O
architecture	B-Architecture
description	I-Architecture
language	I-Architecture
as	O
a	O
computer	B-Language
language	I-Language
to	O
create	O
a	O
description	B-Architecture
of	O
a	O
software	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
In	O
the	O
case	O
of	O
a	O
so-called	O
technical	B-Architecture
architecture	I-Architecture
,	O
the	O
architecture	O
must	O
be	O
communicated	O
to	O
software	O
developers	O
;	O
a	O
functional	O
architecture	O
is	O
communicated	O
to	O
various	O
stakeholders	O
and	O
users	O
.	O
</s>
<s>
Some	O
ADLs	O
that	O
have	O
been	O
developed	O
are	O
:	O
Acme	O
(	O
developed	O
by	O
CMU	O
)	O
,	O
AADL	B-Architecture
(	O
standardized	O
by	O
the	O
SAE	O
)	O
,	O
C2	O
(	O
developed	O
by	O
UCI	O
)	O
,	O
SBC-ADL	O
(	O
developed	O
by	O
National	O
Sun	O
Yat-Sen	O
University	O
)	O
,	O
Darwin	B-General_Concept
(	O
developed	O
by	O
Imperial	O
College	O
London	O
)	O
,	O
and	O
Wright	B-Language
(	O
developed	O
by	O
CMU	O
)	O
.	O
</s>
<s>
The	O
ISO/IEC/IEEE	O
42010	O
document	O
,	O
Systems	O
and	O
software	B-General_Concept
engineering	I-General_Concept
—	O
Architecture	O
description	B-Architecture
,	O
defines	O
an	O
architecture	B-Architecture
description	I-Architecture
language	I-Architecture
as	O
"	O
any	O
form	O
of	O
expression	O
for	O
use	O
in	O
architecture	O
descriptions	O
"	O
and	O
specifies	O
minimum	O
requirements	O
on	O
ADLs	O
.	O
</s>
<s>
The	O
enterprise	O
modelling	O
and	O
engineering	O
community	O
have	O
also	O
developed	O
architecture	B-Architecture
description	I-Architecture
languages	I-Architecture
catered	O
for	O
at	O
the	O
enterprise	O
level	O
.	O
</s>
<s>
Examples	O
include	O
ArchiMate	B-Architecture
(	O
now	O
a	O
standard	O
of	O
The	B-Application
Open	I-Application
Group	I-Application
)	O
,	O
DEMO	O
,	O
ABACUS	O
(	O
developed	O
by	O
the	O
University	O
of	O
Technology	O
,	O
Sydney	O
)	O
.	O
</s>
<s>
Most	O
of	O
them	O
,	O
however	O
,	O
refer	O
to	O
an	O
application	O
architecture	O
as	O
the	O
architecture	O
that	O
is	O
communicated	O
to	O
the	O
software	B-General_Concept
engineers	I-General_Concept
.	O
</s>
<s>
Most	O
of	O
the	O
writing	O
below	O
refers	O
primarily	O
to	O
the	O
perspective	O
from	O
the	O
software	B-General_Concept
engineering	I-General_Concept
community	O
.	O
</s>
<s>
ADLs	O
have	O
been	O
classified	O
into	O
three	O
broad	O
categories	O
:	O
box-and-line	O
informal	O
drawings	O
,	O
formal	O
architecture	B-Architecture
description	I-Architecture
language	I-Architecture
,	O
and	O
UML	B-Language
(	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
)	O
-based	O
notations	O
.	O
</s>
<s>
informality	O
limited	O
the	O
usefulness	O
of	O
the	O
architecture	O
description	B-Architecture
.	O
</s>
<s>
Since	O
then	O
,	O
a	O
thread	O
of	O
research	O
on	O
formal	O
languages	O
for	O
SA	O
description	B-Architecture
has	O
been	O
carried	O
out	O
.	O
</s>
<s>
For	O
example	O
,	O
domain-specific	O
ADLs	O
have	O
been	O
presented	O
to	O
deal	O
with	O
embedded	O
and	O
real-time	O
systems	O
(	O
such	O
as	O
AADL	B-Architecture
,	O
EAST-ADL	B-Architecture
,	O
and	O
EADL	O
)	O
,	O
control-loop	O
applications	O
(	O
DiaSpec	O
)	O
,	O
product	O
line	O
architectures	O
(	O
Koala	O
)	O
,	O
and	O
dynamic	O
systems	O
(Π-	O
ADL	O
)	O
)	O
.	O
</s>
<s>
Analysis-specific	O
ADLs	O
have	O
been	O
proposed	O
to	O
deal	O
with	O
availability	O
,	O
reliability	O
,	O
security	O
,	O
resource	O
consumption	O
,	O
data	O
quality	O
and	O
real-time	O
performance	O
analysis	O
(	O
AADL	B-Architecture
,	O
behavioral	O
analysis	O
(	O
Fractal	O
)	O
)	O
,	O
and	O
trustworthiness	O
analysis	O
(	O
TADL	O
)	O
.	O
</s>
<s>
As	O
a	O
way	O
to	O
overcome	O
some	O
of	O
those	O
limitations	O
,	O
UML	B-Language
has	O
been	O
indicated	O
as	O
a	O
possible	O
successor	O
of	O
existing	O
ADLs	O
.	O
</s>
<s>
Many	O
proposals	O
have	O
been	O
presented	O
to	O
use	O
or	O
extend	O
the	O
UML	B-Language
to	O
more	O
properly	O
model	O
software	B-Architecture
architectures	I-Architecture
.	O
</s>
<s>
The	O
ADL	O
community	O
generally	O
agrees	O
that	O
Software	B-Architecture
Architecture	I-Architecture
is	O
a	O
set	O
of	O
components	O
and	O
the	O
connections	O
among	O
them	O
.	O
</s>
<s>
Architecture	O
,	O
in	O
the	O
context	O
of	O
software	O
systems	O
,	O
is	O
roughly	O
divided	O
into	O
categories	O
,	O
primarily	O
software	B-Architecture
architecture	I-Architecture
,	O
network	O
architecture	O
,	O
and	O
systems	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
Architecture	O
focuses	O
on	O
the	O
partitioning	O
of	O
major	O
regions	O
of	O
functionality	O
into	O
high	O
level	O
components	O
,	O
where	O
they	O
will	O
physically	O
or	O
virtually	O
reside	O
,	O
what	O
off-the-shelf	O
components	O
may	O
be	O
employed	O
effectively	O
,	O
in	O
general	O
what	O
interfaces	O
each	O
component	O
will	O
expose	O
,	O
what	O
protocols	O
will	O
be	O
employed	O
between	O
them	O
,	O
and	O
what	O
practices	O
and	O
high	O
level	O
patterns	O
may	O
best	O
meet	O
extensibility	B-Architecture
,	O
maintainability	O
,	O
reliability	O
,	O
durability	O
,	O
scalability	B-Architecture
,	O
and	O
other	O
non-functional	O
objectives	O
.	O
</s>
