<s>
Multi-user	B-Operating_System
software	I-Operating_System
is	O
computer	O
software	O
that	O
allows	O
access	O
by	O
multiple	B-Operating_System
users	I-Operating_System
of	O
a	O
computer	O
.	O
</s>
<s>
Time-sharing	B-General_Concept
systems	I-General_Concept
are	O
multi-user	B-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Most	O
batch	B-General_Concept
processing	I-General_Concept
systems	O
for	O
mainframe	B-Architecture
computers	I-Architecture
may	O
also	O
be	O
considered	O
"	O
multi-user	B-Operating_System
"	O
,	O
to	O
avoid	O
leaving	O
the	O
CPU	B-General_Concept
idle	O
while	O
it	O
waits	O
for	O
I/O	B-General_Concept
operations	I-General_Concept
to	O
complete	O
.	O
</s>
<s>
However	O
,	O
the	O
term	O
"	O
multitasking	B-Operating_System
"	O
is	O
more	O
common	O
in	O
this	O
context	O
.	O
</s>
<s>
An	O
example	O
is	O
a	O
Unix	B-Application
or	O
Unix-like	B-Operating_System
system	I-Operating_System
where	O
multiple	O
remote	O
users	O
have	O
access	O
(	O
such	O
as	O
via	O
a	O
serial	B-Protocol
port	I-Protocol
or	O
Secure	B-Protocol
Shell	I-Protocol
)	O
to	O
the	O
Unix	B-Application
shell	I-Application
prompt	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Another	O
example	O
uses	O
multiple	O
X	B-Operating_System
Window	I-Operating_System
sessions	O
spread	O
across	O
multiple	O
terminals	O
powered	O
by	O
a	O
single	O
machine	O
–	O
this	O
is	O
an	O
example	O
of	O
the	O
use	O
of	O
thin	B-Device
client	I-Device
.	O
</s>
<s>
Similar	O
functions	O
were	O
also	O
available	O
in	O
a	O
variety	O
of	O
non-Unix-like	O
operating	O
systems	O
,	O
such	O
as	O
Multics	B-Application
,	O
VM/CMS	B-Application
,	O
OpenVMS	B-Operating_System
,	O
MP/M	B-Operating_System
,	O
Concurrent	B-Operating_System
CP/M	I-Operating_System
,	O
Concurrent	B-Operating_System
DOS	I-Operating_System
,	O
FlexOS	B-Operating_System
,	O
Multiuser	B-Operating_System
DOS	I-Operating_System
,	O
REAL/32	B-Operating_System
,	O
OASIS	O
,	O
THEOS	B-Device
,	O
PC-MOS	O
,	O
TSX-32	B-Device
and	O
VM/386	B-Operating_System
.	O
</s>
<s>
Some	O
multi-user	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
such	O
as	O
Windows	O
versions	O
from	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
support	O
simultaneous	O
access	O
by	O
multiple	B-Operating_System
users	I-Operating_System
(	O
for	O
example	O
,	O
via	O
Remote	B-Protocol
Desktop	I-Protocol
Connection	I-Protocol
)	O
as	O
well	O
as	O
the	O
ability	O
for	O
a	O
user	O
to	O
disconnect	O
from	O
a	O
local	O
session	O
while	O
leaving	O
processes	O
running	O
(	O
doing	O
work	O
on	O
their	O
behalf	O
)	O
while	O
another	O
user	O
logs	O
into	O
and	O
uses	O
the	O
system	O
.	O
</s>
<s>
Management	O
systems	O
are	O
implicitly	O
designed	O
to	O
be	O
used	O
by	O
multiple	B-Operating_System
users	I-Operating_System
,	O
typically	O
one	O
system	B-Application
administrator	I-Application
or	O
more	O
and	O
an	O
end-user	O
community	O
.	O
</s>
<s>
The	O
complementary	O
term	O
,	O
single-user	B-Operating_System
,	O
is	O
most	O
commonly	O
used	O
when	O
talking	O
about	O
an	O
operating	O
system	O
being	O
usable	O
only	O
by	O
one	O
person	O
at	O
a	O
time	O
,	O
or	O
in	O
reference	O
to	O
a	O
single-user	B-Operating_System
software	O
license	O
agreement	O
.	O
</s>
<s>
Multi-user	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
such	O
as	O
Unix	B-Application
sometimes	O
have	O
a	O
single	B-Operating_System
user	I-Operating_System
mode	I-Operating_System
or	O
runlevel	B-Device
available	O
for	O
emergency	O
maintenance	O
.	O
</s>
<s>
Examples	O
of	O
single-user	B-Operating_System
operating	O
systems	O
include	O
MS-DOS	B-Application
,	O
OS/2	B-Application
and	O
Classic	B-Application
Mac	I-Application
OS	I-Application
.	O
</s>
