<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
the	O
number	O
of	O
concurrent	B-License
users	I-License
(	O
sometimes	O
abbreviated	O
CCU	O
)	O
for	O
a	O
resource	O
in	O
a	O
location	O
,	O
with	O
the	O
location	O
being	O
a	O
computing	O
network	B-Architecture
or	O
a	O
single	O
computer	O
,	O
refers	O
to	O
the	O
total	O
number	O
of	O
people	O
simultaneously	O
accessing	O
or	O
using	O
the	O
resource	O
.	O
</s>
<s>
The	O
resource	O
can	O
,	O
for	O
example	O
,	O
be	O
a	O
computer	B-Application
program	I-Application
,	O
a	O
file	B-Operating_System
,	O
or	O
the	O
computer	O
as	O
a	O
whole	O
.	O
</s>
<s>
Keeping	O
track	O
of	O
concurrent	B-License
users	I-License
is	O
important	O
in	O
several	O
cases	O
.	O
</s>
<s>
First	O
,	O
some	O
operating	B-General_Concept
system	I-General_Concept
models	O
such	O
as	O
time-sharing	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
allow	O
several	O
users	O
to	O
access	O
a	O
resource	O
on	O
the	O
computer	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
As	O
system	O
performance	O
may	O
degrade	O
due	O
to	O
the	O
complexity	O
of	O
processing	O
multiple	O
jobs	O
from	O
multiple	O
users	O
at	O
the	O
same	O
time	O
,	O
the	O
capacity	O
of	O
such	O
a	O
system	O
may	O
be	O
measured	O
in	O
terms	O
of	O
maximum	O
concurrent	B-License
users	I-License
.	O
</s>
<s>
Second	O
,	O
commercial	O
software	O
vendors	O
often	O
license	B-License
a	I-License
software	I-License
product	I-License
by	O
means	O
of	O
a	O
concurrent	B-License
users	I-License
restriction	O
.	O
</s>
<s>
For	O
example	O
:	O
Company	O
X	O
buys	O
software	O
and	O
pays	O
for	O
20	O
concurrent	B-License
users	I-License
.	O
</s>
<s>
Only	O
20	O
of	O
those	O
100	O
can	O
be	O
in	O
the	O
system	O
at	O
the	O
same	O
time	O
,	O
this	O
is	O
known	O
as	O
floating	B-Application
licensing	I-Application
.	O
</s>
<s>
Concurrent	B-License
user	I-License
licensing	O
allows	O
firms	O
to	O
purchase	O
computer	O
systems	O
and	O
software	O
at	O
a	O
lower	O
cost	O
because	O
the	O
maximum	O
number	O
of	O
concurrent	B-License
users	I-License
expected	O
to	O
use	O
the	O
system	O
or	O
software	O
at	O
any	O
given	O
time	O
(	O
those	O
users	O
all	O
logged	O
in	O
together	O
)	O
is	O
only	O
a	O
portion	O
of	O
the	O
total	O
system	O
users	O
employed	O
at	O
a	O
company	O
.	O
</s>
<s>
This	O
contrasts	O
with	O
"	O
named-seats	B-License
"	O
licensing	O
,	O
in	O
which	O
one	O
license	O
must	O
be	O
purchased	O
for	O
each	O
and	O
every	O
individual	O
user	O
,	O
whether	O
they	O
are	O
using	O
the	O
system	O
or	O
not	O
.	O
</s>
<s>
If	O
a	O
company	O
employs	O
400	O
system	O
users	O
in	O
which	O
275	O
work	O
during	O
the	O
day	O
and	O
125	O
work	O
at	O
night	O
,	O
then	O
they	O
can	O
opt	O
to	O
purchase	O
only	O
275	O
concurrent	B-Application
user	I-Application
licenses	I-Application
since	O
there	O
will	O
never	O
be	O
more	O
than	O
275	O
users	O
on	O
the	O
system	O
during	O
a	O
normal	O
work	O
day	O
.	O
</s>
