<s>
Axum	B-Language
(	O
previously	O
codenamed	O
Maestro	O
)	O
is	O
a	O
domain-specific	B-Language
concurrent	B-Architecture
programming	I-Architecture
language	O
,	O
based	O
on	O
the	O
Actor	B-Application
model	I-Application
,	O
that	O
was	O
under	O
active	O
development	O
by	O
Microsoft	O
between	O
2009	O
and	O
2011	O
.	O
</s>
<s>
It	O
is	O
an	O
object-oriented	B-Language
language	I-Language
based	O
on	O
the	O
.NET	B-Application
Common	O
Language	O
Runtime	O
using	O
a	O
C-like	O
syntax	O
which	O
,	O
being	O
a	O
domain-specific	B-Language
language	I-Language
,	O
is	O
intended	O
for	O
development	O
of	O
portions	O
of	O
a	O
software	O
application	O
that	O
is	O
well-suited	O
to	O
concurrency	B-Architecture
.	O
</s>
<s>
But	O
it	O
contains	O
enough	O
general-purpose	O
constructs	O
that	O
one	O
need	O
not	O
switch	O
to	O
a	O
general-purpose	O
programming	O
language	O
(	O
like	O
C#	B-Application
)	O
for	O
the	O
sequential	O
parts	O
of	O
the	O
concurrent	B-Architecture
components	O
.	O
</s>
<s>
The	O
main	O
idiom	O
of	O
programming	O
in	O
Axum	B-Language
is	O
an	O
Agent	O
(	O
or	O
an	O
Actor	O
)	O
,	O
which	O
is	O
an	O
isolated	O
entity	O
that	O
executes	O
in	O
parallel	O
with	O
other	O
Agents	O
.	O
</s>
<s>
In	O
Axum	B-Language
parlance	O
,	O
this	O
is	O
referred	O
to	O
as	O
the	O
agents	O
executing	O
in	O
separate	O
isolation	O
domains	O
;	O
objects	O
instantiated	O
within	O
a	O
domain	O
cannot	O
be	O
directly	O
accessed	O
from	O
another	O
.	O
</s>
<s>
Agents	O
are	O
loosely	O
coupled	O
(	O
i.e.	O
,	O
the	O
number	O
of	O
dependencies	O
between	O
agents	O
is	O
minimal	O
)	O
and	O
do	O
not	O
share	O
resources	O
like	O
memory	O
(	O
unlike	O
the	O
shared	B-Operating_System
memory	I-Operating_System
model	O
of	O
C#	B-Application
and	O
similar	O
languages	O
)	O
;	O
instead	O
a	O
message	B-Architecture
passing	I-Architecture
model	O
is	O
used	O
.	O
</s>
<s>
Axum	B-Language
provides	O
Channels	O
to	O
facilitate	O
this	O
.	O
</s>
<s>
A	O
Channel	O
contains	O
input	O
and	O
output	O
ports	O
,	O
which	O
are	O
queues	B-Application
which	O
are	O
used	O
to	O
send	O
data	O
to	O
an	O
agent	O
or	O
receive	O
data	O
from	O
one	O
.	O
</s>
<s>
To	O
co-ordinate	O
the	O
communication	O
between	O
agents	O
,	O
Axum	B-Language
allows	O
each	O
channel	O
to	O
have	O
a	O
user-defined	O
protocol	O
for	O
communication	O
.	O
</s>
<s>
The	O
protocol	O
is	O
defined	O
as	O
a	O
state	B-Architecture
machine	I-Architecture
.	O
</s>
<s>
Under	O
the	O
hood	O
,	O
a	O
schema	O
is	O
translated	O
into	O
a	O
serializable	B-Application
.NET	B-Application
class	O
that	O
contains	O
only	O
properties	O
and	O
side	O
effect-free	O
methods	O
.	O
</s>
<s>
The	O
Axum	B-Language
project	O
reached	O
the	O
state	O
of	O
a	O
prototype	O
with	O
working	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
integration	O
.	O
</s>
<s>
Microsoft	O
had	O
made	O
a	O
CTP	O
of	O
Axum	B-Language
available	O
to	O
the	O
public	O
,	O
but	O
this	O
has	O
since	O
been	O
removed	O
.	O
</s>
<s>
Although	O
Microsoft	O
decided	O
not	O
to	O
turn	O
Axum	B-Language
into	O
a	O
project	O
,	O
some	O
of	O
the	O
ideas	O
behind	O
Axum	B-Language
are	O
used	O
in	O
TPL	O
Dataflow	O
in	O
.Net	B-Application
4.5	O
.	O
</s>
