<s>
Win32s	B-Library
is	O
a	O
32-bit	O
application	O
runtime	O
environment	O
for	O
the	O
Microsoft	B-Application
Windows	I-Application
3.1	I-Application
and	O
3.11	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
It	O
allowed	O
some	O
32-bit	O
applications	O
to	O
run	O
on	O
the	O
16-bit	B-Device
operating	B-General_Concept
system	I-General_Concept
using	O
call	O
thunks	B-Application
.	O
</s>
<s>
A	O
beta	O
version	O
of	O
Win32s	B-Library
was	O
available	O
in	O
October	O
1992	O
.	O
</s>
<s>
Version	O
1.10	O
was	O
released	O
in	O
July	O
1993	O
simultaneously	O
with	O
Windows	B-Device
NT	I-Device
3.1	I-Device
.	O
</s>
<s>
Win32s	B-Library
was	O
intended	O
as	O
a	O
partial	O
implementation	O
of	O
the	O
Win32	B-Library
Windows	I-Library
API	I-Library
as	O
it	O
existed	O
in	O
early	O
versions	O
of	O
Windows	B-Device
NT	I-Device
.	O
</s>
<s>
The	O
"	O
s	O
"	O
in	O
Win32s	B-Library
signifies	O
subset	O
,	O
as	O
Win32s	B-Library
lacked	O
a	O
number	O
of	O
Windows	B-Device
NT	I-Device
functions	O
,	O
including	O
multi-threading	B-Operating_System
,	O
asynchronous	B-Architecture
I/O	I-Architecture
,	O
newer	O
serial	B-Protocol
port	I-Protocol
functions	O
and	O
many	O
GDI	B-Operating_System
extensions	O
.	O
</s>
<s>
This	O
generally	O
limited	O
it	O
to	O
"	O
Win32s	B-Library
applications	O
"	O
which	O
were	O
specifically	O
designed	O
for	O
the	O
Win32s	B-Library
platform	O
,	O
although	O
some	O
standard	O
Win32	B-Library
programs	O
would	O
work	O
correctly	O
,	O
including	O
Microsoft	O
's	O
3D	O
Pinball	O
Space	O
Cadet	O
and	O
some	O
of	O
Windows	B-Application
95	I-Application
's	O
included	O
applets	O
.	O
</s>
<s>
Early	O
versions	O
of	O
Internet	O
Explorer	O
(	O
up	O
to	O
Version	O
5	O
)	O
were	O
also	O
Win32s	B-Library
compatible	O
,	O
although	O
these	O
also	O
existed	O
in	O
16-bit	B-Device
format	O
.	O
</s>
<s>
Generally	O
,	O
for	O
a	O
32-bit	O
application	O
to	O
be	O
compatible	O
with	O
Win32s	B-Library
,	O
it	O
had	O
to	O
not	O
use	O
more	O
than	O
16MB	O
of	O
memory	O
or	O
any	O
extended	O
features	O
such	O
as	O
DirectX	B-Application
.	O
</s>
<s>
Win32s	B-Library
inherits	O
many	O
of	O
the	O
limitations	O
of	O
the	O
Win16	B-Library
environment	O
.	O
</s>
<s>
True	O
Win32	B-Library
applications	O
execute	O
within	O
a	O
private	O
virtual	O
address	O
space	O
,	O
whereas	O
Windows	O
3.x	O
used	O
an	O
address	O
space	O
shared	O
among	O
all	O
running	O
applications	O
.	O
</s>
<s>
An	O
application	O
running	O
on	O
Win32s	B-Library
has	O
the	O
shared	O
address	O
space	O
and	O
cooperative	O
multitasking	O
characteristics	O
of	O
Windows	B-Application
3.1	I-Application
.	O
</s>
<s>
Consequently	O
,	O
for	O
a	O
Win32	B-Library
application	O
to	O
run	O
on	O
Win32s	B-Library
,	O
it	O
must	O
contain	O
relocation	B-Library
information	I-Library
.	O
</s>
<s>
A	O
technique	O
named	O
thunking	B-Application
is	O
fundamental	O
to	O
the	O
implementation	O
of	O
Win32s	B-Library
as	O
well	O
as	O
Chicago-kernel	O
operating	B-General_Concept
systems	I-General_Concept
,	O
which	O
are	O
Windows	B-Application
95	I-Application
,	O
Windows	B-Device
98	I-Device
,	O
and	O
Windows	B-Device
ME	I-Device
.	O
</s>
<s>
However	O
,	O
allowing	O
user-level	O
thunking	B-Application
greatly	O
complicates	O
attempts	O
to	O
provide	O
stable	O
memory	O
management	O
or	O
memory	O
protection	O
on	O
a	O
system-wide	O
basis	O
,	O
as	O
well	O
as	O
core	O
or	O
kernel	O
securitythis	O
allows	O
poorly	O
written	O
applications	O
to	O
undermine	O
system	O
stability	O
on	O
Win32s	B-Library
,	O
as	O
well	O
as	O
the	O
Chicago-kernel	O
systems	O
.	O
</s>
<s>
32-bit	O
versions	O
of	O
Windows	B-Device
NT	I-Device
transparently	O
provide	O
a	O
virtual	O
machine	O
for	O
running	O
Win16	B-Library
applications	O
,	O
although	O
this	B-Application
feature	I-Application
was	O
removed	O
from	O
64-bit	O
versions	O
of	O
Windows	O
.	O
</s>
<s>
Win32s-compatible	O
applications	O
could	O
be	O
built	O
using	O
Microsoft	O
's	O
development	O
tools	O
,	O
as	O
well	O
as	O
at	O
least	O
Borland	B-Application
C++	I-Application
4.x	O
and	O
Symantec	O
C++	O
(	O
now	O
Digital	B-Language
Mars	I-Language
C++	I-Language
)	O
.	O
</s>
<s>
However	O
,	O
several	O
program	O
compilation	O
options	O
(	O
such	O
as	O
EXE	O
relocation	B-Library
information	I-Library
)	O
and	O
DLLs	O
which	O
were	O
implicit	O
in	O
Windows	B-Device
NT	I-Device
3.1	I-Device
have	O
to	O
be	O
included	O
with	O
the	O
application	O
in	O
Win32s	B-Library
.	O
</s>
<s>
Microsoft	O
ceased	O
support	O
for	O
Win32s	B-Library
in	O
Visual	B-Application
C++	I-Application
version	O
4.2	O
released	O
in	O
late	O
1996	O
.	O
</s>
<s>
Win32s	B-Library
included	O
an	O
implementation	O
of	O
the	O
card	O
game	O
FreeCell	B-Application
as	O
an	O
example	O
application	O
,	O
a	O
couple	O
of	O
years	O
before	O
the	O
game	O
became	O
famous	O
with	O
its	O
inclusion	O
in	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
Warcraft	B-Application
II	I-Application
:	I-Application
Tides	I-Application
of	I-Application
Darkness	I-Application
,	O
a	O
DOS	O
game	O
,	O
included	O
a	O
level	O
editor	O
that	O
required	O
Win32s	B-Library
to	O
run	O
.	O
</s>
<s>
The	O
NCSA	B-Application
Mosaic	I-Application
web	B-Application
browser	I-Application
version	O
2	O
also	O
required	O
Win32s	B-Library
.	O
</s>
<s>
C#	B-Application
applications	O
can	O
be	O
compiled	O
by	O
the	O
CoreRT	B-Application
compiler	O
into	O
Win32	B-Library
code	O
that	O
is	O
accepted	O
by	O
the	O
1994	O
Visual	B-Application
C++	I-Application
linker	O
.	O
</s>
<s>
This	O
combination	O
produces	O
Win32	B-Library
executables	O
that	O
can	O
run	O
on	O
Windows	B-Application
3.1	I-Application
with	O
Win32s	B-Library
.	O
</s>
<s>
Win32s	B-Library
can	O
still	O
be	O
found	O
using	O
web	O
search	O
engines	O
;	O
PW1118.EXE	O
is	O
generally	O
the	O
installation	O
file	O
used	O
.	O
</s>
<s>
Developers	O
should	O
ensure	O
they	O
are	O
installing	O
OLE	B-Operating_System
if	O
they	O
require	O
consistent	O
clipboard	O
handling	O
.	O
</s>
<s>
Many	O
applications	O
which	O
need	O
to	O
be	O
made	O
OLE	B-Operating_System
aware	O
(	O
i.e.	O
</s>
<s>
setting	O
up	O
their	O
OLE	B-Operating_System
server	I-Operating_System
)	O
must	O
be	O
reinstalled	O
.	O
</s>
<s>
Win32s	B-Library
was	O
also	O
included	O
with	O
some	O
early	O
Win32	B-Library
programs	O
.	O
</s>
