<s>
Open	B-Application
Rack	I-Application
is	O
an	O
Open	B-Operating_System
Compute	I-Operating_System
Project	I-Operating_System
standard	O
for	O
a	O
new	O
rack	B-Application
and	O
power	O
delivery	O
architecture	O
and	O
an	O
efficient	O
,	O
scalable	O
alternative	O
to	O
the	O
.	O
</s>
<s>
It	O
differs	O
from	O
the	O
traditional	O
EIA-310	O
19	B-Application
"	I-Application
rack	I-Application
in	O
that	O
it	O
was	O
designed	O
specifically	O
for	O
large	O
scale	O
cloud	B-Architecture
deployments	O
.	O
</s>
<s>
There	O
are	O
four	O
key	O
features	O
that	O
make	O
this	O
rack	B-Application
design	O
more	O
efficient	O
to	O
deploy	O
,	O
support	O
,	O
and	O
operate	O
.	O
</s>
<s>
The	O
power	O
to	O
all	O
of	O
the	O
compute	O
,	O
storage	O
,	O
or	O
network	O
devices	O
is	O
supplied	O
by	O
a	O
pair	O
of	O
bus	O
bars	O
located	O
in	O
the	O
rear	O
of	O
the	O
rack	B-Application
.	O
</s>
<s>
The	O
IT	O
equipment	O
that	O
fits	O
into	O
Open	B-Application
Rack	I-Application
is	O
21	O
"	O
or	O
538mm	O
wide	O
.	O
</s>
<s>
All	O
of	O
the	O
cables	O
and	O
interconnects	O
are	O
made	O
from	O
the	O
front	O
of	O
the	O
rack	B-Application
and	O
the	O
IT	O
equipment	O
is	O
hot-pluggable	B-Device
and	O
serviceable	O
from	O
the	O
front	O
of	O
the	O
rack	B-Application
.	O
</s>
<s>
Service	O
personnel	O
no	O
longer	O
access	O
the	O
rear	O
of	O
the	O
rack	B-Application
or	O
need	O
to	O
work	O
in	O
the	O
hot	O
aisle	O
.	O
</s>
<s>
Open	B-Application
Rack	I-Application
rack	B-Application
units	O
are	O
called	O
OpenU	O
or	O
just	O
OU	O
.	O
</s>
<s>
An	O
Open	B-Application
Rack	I-Application
consists	O
of	O
three	O
modular	O
zones	O
:	O
power	O
,	O
equipment	O
,	O
and	O
cable	O
.	O
</s>
