<s>
In	O
computer	B-Application
software	I-Application
,	O
an	O
operating	B-Application
environment	I-Application
or	O
integrated	B-Application
applications	I-Application
environment	I-Application
is	O
the	O
environment	O
in	O
which	O
users	O
run	O
application	B-Application
software	I-Application
.	O
</s>
<s>
The	O
environment	O
consists	O
of	O
a	O
user	B-Application
interface	I-Application
provided	O
by	O
an	O
applications	B-Application
manager	I-Application
and	O
usually	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
to	O
the	O
applications	B-Application
manager	I-Application
.	O
</s>
<s>
An	O
operating	B-Application
environment	I-Application
is	O
not	O
a	O
full	O
operating	B-General_Concept
system	I-General_Concept
,	O
but	O
is	O
a	O
form	O
of	O
middleware	B-General_Concept
that	O
rests	O
between	O
the	O
OS	O
and	O
the	O
application	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
first	O
version	O
of	O
Microsoft	B-Application
Windows	I-Application
,	O
Windows	B-Application
1.0	I-Application
,	O
was	O
not	O
a	O
full	O
operating	B-General_Concept
system	I-General_Concept
,	O
but	O
a	O
GUI	B-Application
laid	O
over	O
DOS	B-Device
albeit	O
with	O
an	O
API	B-Application
of	O
its	O
own	O
.	O
</s>
<s>
Similarly	O
,	O
the	O
IBM	B-Application
U2	I-Application
system	O
operates	O
on	O
both	O
Unix/Linux	O
and	O
Windows	B-Device
NT	I-Device
.	O
</s>
<s>
Usually	O
the	O
user	B-Application
interface	I-Application
is	O
text-based	B-Application
or	O
graphical	B-Application
,	O
rather	O
than	O
a	O
command-line	B-Application
interface	I-Application
(	O
e.g.	O
,	O
DOS	B-Device
or	O
the	O
Unix	B-Application
shell	I-Application
)	O
,	O
which	O
is	O
often	O
the	O
interface	O
of	O
the	O
underlying	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
In	O
the	O
mid	O
1980s	O
,	O
text-based	B-Application
and	O
graphical	B-Application
user	I-Application
interface	I-Application
operating	B-Application
environments	I-Application
surrounded	O
DOS	B-Device
operating	B-General_Concept
systems	I-General_Concept
with	O
a	O
shell	B-Operating_System
that	O
turned	O
the	O
user	O
's	O
display	B-Device
into	O
a	O
menu-oriented	O
"	O
desktop	B-Application
"	O
for	O
selecting	O
and	O
running	O
PC	O
applications	O
.	O
</s>
<s>
These	O
operating	B-Application
environment	I-Application
systems	O
allow	O
users	O
much	O
of	O
the	O
convenience	O
of	O
integrated	B-Application
software	I-Application
without	O
locking	O
them	O
into	O
a	O
single	O
package	O
.	O
</s>
<s>
In	O
the	O
mid	O
1980s	O
,	O
text-based	B-Application
and	O
graphical	B-Application
user	I-Application
interface	I-Application
operating	B-Application
environments	I-Application
such	O
as	O
IBM	B-Operating_System
TopView	I-Operating_System
,	O
Microsoft	B-Application
Windows	I-Application
,	O
Digital	O
Research	O
's	O
GEM	B-Application
Desktop	I-Application
,	O
GEOS	B-Application
and	O
Quarterdeck	O
Office	O
Systems	O
's	O
DESQview	B-Operating_System
surrounded	O
DOS	B-Device
operating	B-General_Concept
systems	I-General_Concept
with	O
a	O
shell	B-Operating_System
that	O
turned	O
the	O
user	O
's	O
display	B-Device
into	O
a	O
menu-oriented	O
"	O
desktop	B-Application
"	O
for	O
selecting	O
and	O
running	O
PC	O
applications	O
.	O
</s>
<s>
These	O
programs	O
were	O
more	O
than	O
simple	O
menu	O
systems	O
—	O
as	O
alternate	O
operating	B-Application
environments	I-Application
they	O
were	O
substitutes	O
for	O
integrated	O
programs	O
such	O
as	O
Framework	B-Application
and	O
Symphony	B-Application
,	O
that	O
allowed	O
switching	B-Operating_System
,	O
windowing	B-Application
,	O
and	O
cut-and-paste	B-General_Concept
operations	O
among	O
dedicated	O
applications	O
.	O
</s>
<s>
These	O
operating	B-Application
environment	I-Application
systems	O
gave	O
users	O
much	O
of	O
the	O
convenience	O
of	O
integrated	B-Application
software	I-Application
without	O
locking	O
them	O
into	O
a	O
single	O
package	O
.	O
</s>
<s>
Alternative	O
operating	B-Application
environments	I-Application
made	O
terminate-and-stay-resident	O
pop-up	O
utilities	O
such	O
as	O
Borland	B-Application
Sidekick	I-Application
redundant	O
.	O
</s>
<s>
Windows	O
provided	O
its	O
own	O
version	O
of	O
these	O
utilities	O
,	O
and	O
placing	O
them	O
under	O
central	O
control	O
could	O
eliminate	O
memory	O
conflicts	O
that	O
RAM-resident	O
utilities	O
create	O
.	O
</s>
<s>
In	O
later	O
versions	O
,	O
Windows	O
evolved	O
from	O
an	O
operating	B-Application
environment	I-Application
into	O
a	O
complete	O
operating	B-General_Concept
system	I-General_Concept
with	O
DOS	B-Device
as	O
a	O
bootloader	O
(	O
Windows	O
9x	O
)	O
and	O
a	O
complete	O
operating	B-General_Concept
system	I-General_Concept
,	O
Windows	B-Device
NT	I-Device
,	O
was	O
developed	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
All	O
versions	O
after	O
Windows	B-Device
ME	I-Device
have	O
been	O
based	O
on	O
the	O
Windows	B-Device
NT	I-Device
kernel	O
.	O
</s>
