<s>
DOSEMU	B-Application
,	O
stylized	O
as	O
dosemu	B-Application
,	O
is	O
a	O
compatibility	B-General_Concept
layer	I-General_Concept
software	O
package	O
that	O
enables	O
DOS	B-Operating_System
operating	O
systems	O
(	O
e.g.	O
,	O
MS-DOS	B-Application
,	O
DR-DOS	B-Application
,	O
FreeDOS	B-Application
)	O
and	O
application	B-Application
software	I-Application
to	O
run	O
atop	O
Linux	B-Application
on	O
x86-based	O
PCs	O
(	O
IBM	O
PC	O
compatible	O
computers	O
)	O
.	O
</s>
<s>
It	O
uses	O
a	O
combination	O
of	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
features	O
and	O
high-level	B-Device
emulation	I-Device
.	O
</s>
<s>
It	O
can	O
thus	O
achieve	O
nearly	O
native	O
speed	O
for	O
8086-compatible	O
DOS	B-Operating_System
operating	O
systems	O
and	O
applications	O
on	O
x86	B-Operating_System
compatible	I-Operating_System
processors	O
,	O
and	O
for	O
DOS	B-Operating_System
Protected	O
Mode	O
Interface	O
(	O
DPMI	O
)	O
applications	O
on	O
x86	B-Operating_System
compatible	I-Operating_System
processors	O
as	O
well	O
as	O
on	O
x86-64	B-Device
processors	O
.	O
</s>
<s>
DOSEMU	B-Application
includes	O
an	O
8086	O
processor	O
emulator	O
for	O
use	O
with	O
real-mode	O
applications	O
in	O
x86-64	B-Device
long	B-Application
mode	I-Application
.	O
</s>
<s>
DOSEMU	B-Application
is	O
only	O
available	O
for	O
x86	B-Operating_System
and	O
x86-64	B-Device
Linux	B-Application
systems	O
(	O
Linux	B-Application
3.15	O
x86-64	B-Device
systems	O
cannot	O
enter	O
DPMI	O
by	O
default	O
.	O
</s>
<s>
DOSEMU	B-Application
is	O
an	O
option	O
for	O
people	O
who	O
need	O
or	O
want	O
to	O
continue	O
to	O
use	O
legacy	O
DOS	B-Operating_System
software	O
;	O
in	O
some	O
cases	O
virtualisation	O
is	O
good	O
enough	O
to	O
drive	O
external	O
hardware	O
such	O
as	O
device	B-General_Concept
programmers	I-General_Concept
connected	O
to	O
the	O
parallel	B-Device
port	I-Device
.	O
</s>
<s>
According	O
to	O
its	O
manual	O
,	O
"	O
dosemu	B-Application
"	O
is	O
a	O
user-level	O
program	O
which	O
uses	O
certain	O
special	O
features	O
of	O
the	O
Linux	B-Application
kernel	O
and	O
the	O
80386	O
processor	O
to	O
run	O
DOS	B-Operating_System
in	O
a	O
DOS	B-Application
box	I-Application
.	O
</s>
<s>
The	O
DOS	B-Application
box	I-Application
,	O
relying	O
on	O
a	O
combination	O
of	O
hardware	O
and	O
software	O
,	O
has	O
these	O
abilities	O
:	O
</s>
<s>
Simulate	O
a	O
hardware	O
environment	O
over	O
which	O
DOS	B-Operating_System
programs	O
are	O
accustomed	O
to	O
having	O
control	O
.	O
</s>
<s>
Provide	O
DOS	B-Operating_System
services	O
through	O
native	O
Linux	B-Application
services	O
;	O
for	O
example	O
,	O
dosemu	B-Application
can	O
provide	O
a	O
virtual	O
hard	O
disk	O
drive	O
which	O
is	O
actually	O
a	O
Linux	B-Application
directory	O
hierarchy	O
.	O
</s>
<s>
API-level	B-Application
support	O
for	O
Packet	B-Application
driver	I-Application
,	O
IPX	B-Protocol
,	O
Berkeley	B-Protocol
sockets	I-Protocol
(	O
dosnet	O
)	O
.	O
</s>
