<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
is	O
a	O
scalable	O
data	O
storage	O
and	O
analytics	O
service	O
.	O
</s>
<s>
The	O
service	O
is	O
hosted	O
in	O
Azure	B-Application
,	O
Microsoft	O
's	O
public	O
cloud	O
.	O
</s>
<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
service	O
was	O
released	O
on	O
November	O
16	O
,	O
2016	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
COSMOS	O
,	O
which	O
is	O
used	O
to	O
store	O
and	O
process	O
data	O
for	O
applications	O
such	O
as	O
Azure	B-Application
,	O
AdCenter	B-Application
,	O
Bing	B-Application
,	O
MSN	B-Protocol
,	O
Skype	B-Application
and	O
Windows	O
Live	O
.	O
</s>
<s>
COSMOS	O
features	O
a	O
SQL-like	O
query	O
engine	O
called	O
SCOPE	O
upon	O
which	O
U-SQL	O
was	O
built	O
.	O
</s>
<s>
Users	O
can	O
store	O
structured	O
,	O
semi-structured	O
or	O
unstructured	B-Application
data	I-Application
produced	O
from	O
applications	O
including	O
social	O
networks	O
,	O
relational	O
data	O
,	O
sensors	O
,	O
videos	O
,	O
web	O
apps	O
,	O
mobile	O
or	O
desktop	O
devices	O
.	O
</s>
<s>
A	O
single	O
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
Store	O
account	O
can	O
store	O
trillions	O
of	O
files	O
where	O
a	O
single	O
file	O
can	O
be	O
greater	O
than	O
a	O
petabyte	O
in	O
size	O
.	O
</s>
<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
Analytics	O
is	O
a	O
parallel	O
on-demand	O
job	O
service	O
.	O
</s>
<s>
The	O
parallel	O
processing	O
system	O
is	O
based	O
on	O
Microsoft	B-Operating_System
Dryad	I-Operating_System
.	O
</s>
<s>
Dryad	B-Operating_System
can	O
represent	O
arbitrary	O
Directed	O
Acyclic	O
Graphs	O
(	O
DAGs	O
)	O
of	O
computation	O
.	O
</s>
<s>
Data	B-General_Concept
Lake	I-General_Concept
Analytics	O
provides	O
a	O
distributed	O
infrastructure	O
that	O
can	O
dynamically	O
allocate	O
or	O
de-allocate	O
resources	O
so	O
customers	O
pay	O
for	O
only	O
the	O
services	O
they	O
use	O
.	O
</s>
<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
Analytics	O
uses	O
Apache	O
YARN	B-Application
,	O
the	O
part	O
of	O
Apache	B-Application
Hadoop	I-Application
which	O
governs	O
resource	O
management	O
across	O
clusters	O
.	O
</s>
<s>
Microsoft	B-Application
Azure	I-Application
Data	B-General_Concept
Lake	I-General_Concept
Store	O
supports	O
any	O
application	O
that	O
uses	O
the	O
Hadoop	B-Application
Distributed	O
File	O
System	O
(	O
HDFS	O
)	O
interface	O
.	O
</s>
<s>
Using	O
Data	B-General_Concept
Lake	I-General_Concept
Analytics	O
,	O
users	O
can	O
develop	O
and	O
run	O
parallel	B-General_Concept
data	I-General_Concept
transformation	I-General_Concept
and	O
processing	O
programs	O
in	O
U-SQL	O
,	O
a	O
query	O
language	O
that	O
combines	O
SQL	B-Language
with	O
C#	B-Application
.	O
</s>
<s>
U-SQL	O
was	O
designed	O
as	O
an	O
evolution	O
of	O
the	O
declarative	O
SQL	B-Language
language	I-Language
with	O
native	O
extensibility	O
through	O
the	O
user	O
code	O
written	O
in	O
C#	B-Application
.	O
</s>
<s>
U-SQL	O
uses	O
C#	B-Application
data	O
types	O
and	O
the	O
C#	B-Application
expression	O
language	O
.	O
</s>
