<s>
MS-DOS	B-Application
(	O
;	O
acronym	O
for	O
Microsoft	O
Disk	B-Operating_System
Operating	I-Operating_System
System	I-Operating_System
,	O
also	O
known	O
as	O
Microsoft	O
DOS	B-Device
)	O
is	O
an	O
operating	B-General_Concept
system	I-General_Concept
for	O
x86-based	O
personal	B-Device
computers	I-Device
mostly	O
developed	O
by	O
Microsoft	O
.	O
</s>
<s>
Collectively	O
,	O
MS-DOS	B-Application
,	O
its	O
rebranding	O
as	O
IBM	B-Device
PC	I-Device
DOS	B-Device
,	O
and	O
a	O
few	O
operating	B-General_Concept
systems	I-General_Concept
attempting	O
to	O
be	O
compatible	O
with	O
MS-DOS	B-Application
,	O
are	O
sometimes	O
referred	O
to	O
as	O
"	O
DOS	B-Device
"	O
(	O
which	O
is	O
also	O
the	O
generic	O
acronym	O
for	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
)	O
.	O
</s>
<s>
MS-DOS	B-Application
was	O
the	O
main	O
operating	B-General_Concept
system	I-General_Concept
for	O
IBM	B-Device
PC	I-Device
compatibles	O
during	O
the	O
1980s	O
,	O
from	O
which	O
point	O
it	O
was	O
gradually	O
superseded	O
by	O
operating	B-General_Concept
systems	I-General_Concept
offering	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
,	O
in	O
various	O
generations	O
of	O
the	O
graphical	O
Microsoft	B-Application
Windows	I-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
IBM	O
licensed	O
and	O
re-released	O
it	O
in	O
1981	O
as	O
PC	O
DOS	B-Device
1.0	O
for	O
use	O
in	O
its	O
PCs	B-Device
.	O
</s>
<s>
Although	O
MS-DOS	B-Application
and	O
PCDOS	B-Operating_System
were	O
initially	O
developed	O
in	O
parallel	O
by	O
Microsoft	O
and	O
IBM	O
,	O
the	O
two	O
products	O
diverged	O
after	O
twelve	O
years	O
,	O
in	O
1993	O
,	O
with	O
recognizable	O
differences	O
in	O
compatibility	O
,	O
syntax	O
,	O
and	O
capabilities	O
.	O
</s>
<s>
Beginning	O
in	O
1988	O
with	O
DR-DOS	B-Application
,	O
several	O
competing	O
products	O
were	O
released	O
for	O
the	O
x86	B-Operating_System
platform	O
,	O
and	O
MS-DOS	B-Application
went	O
through	O
eight	O
versions	O
,	O
until	O
development	O
ceased	O
in	O
2000	B-Application
.	O
</s>
<s>
Initially	O
,	O
MS-DOS	B-Application
was	O
targeted	O
at	O
Intel	B-General_Concept
8086	I-General_Concept
processors	O
running	O
on	O
computer	O
hardware	O
using	O
floppy	B-Device
disks	I-Device
to	O
store	O
and	O
access	O
not	O
only	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
but	O
application	B-Application
software	I-Application
and	O
user	O
data	O
as	O
well	O
.	O
</s>
<s>
It	O
was	O
also	O
the	O
underlying	O
basic	O
operating	B-General_Concept
system	I-General_Concept
on	O
which	O
early	O
versions	O
of	O
Windows	O
ran	O
as	O
a	O
GUI	B-Application
.	O
</s>
<s>
MS-DOS	B-Application
was	O
a	O
renamed	O
form	O
of	O
86-DOS	B-Operating_System
owned	O
by	O
Seattle	O
Computer	O
Products	O
,	O
written	O
by	O
Tim	O
Paterson	O
.	O
</s>
<s>
Development	O
of	O
86-DOS	B-Operating_System
took	O
only	O
six	O
weeks	O
,	O
as	O
it	O
was	O
basically	O
a	O
clone	O
of	O
Digital	O
Research	O
's	O
CP/M	B-Application
(	O
for	O
8080/Z80	O
processors	O
)	O
,	O
ported	O
to	O
run	O
on	O
8086	B-General_Concept
processors	O
and	O
with	O
two	O
notable	O
differences	O
compared	O
to	O
CP/M	B-Application
:	O
an	O
improved	O
disk	O
sector	O
buffering	O
logic	O
,	O
and	O
the	O
introduction	O
of	O
FAT12	B-Application
instead	O
of	O
the	O
CP/M	B-Application
filesystem	O
.	O
</s>
<s>
Microsoft	O
,	O
which	O
needed	O
an	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
IBM	B-Device
Personal	I-Device
Computer	I-Device
,	O
hired	O
Tim	O
Paterson	O
in	O
May	O
1981	O
and	O
bought	O
86-DOS	B-Operating_System
1.10	O
for	O
in	O
July	O
of	O
the	O
same	O
year	O
.	O
</s>
<s>
Microsoft	O
kept	O
the	O
version	O
number	O
,	O
but	O
renamed	O
it	O
MS-DOS	B-Application
.	O
</s>
<s>
They	O
also	O
licensed	O
MS-DOS	B-Application
1.10/1.14	O
to	O
IBM	O
,	O
which	O
,	O
in	O
August	O
1981	O
,	O
offered	O
it	O
as	O
PC	B-Operating_System
DOS	I-Operating_System
1.0	O
as	O
one	O
of	O
three	O
operating	B-General_Concept
systems	I-General_Concept
for	O
the	O
IBM	B-Device
5150	I-Device
or	O
the	O
IBM	B-Device
PC	I-Device
.	O
</s>
<s>
Within	O
a	O
year	O
,	O
Microsoft	O
licensed	O
MS-DOS	B-Application
to	O
over	O
70	O
other	O
companies	O
.	O
</s>
<s>
It	O
was	O
designed	O
to	O
be	O
an	O
OS	O
that	O
could	O
run	O
on	O
any	O
8086-family	O
computer	O
.	O
</s>
<s>
Each	O
computer	O
would	O
have	O
its	O
own	O
distinct	O
hardware	O
and	O
its	O
own	O
version	O
of	O
MS-DOS	B-Application
,	O
similar	O
to	O
the	O
situation	O
that	O
existed	O
for	O
CP/M	B-Application
,	O
and	O
with	O
MS-DOS	B-Application
emulating	O
the	O
same	O
solution	O
as	O
CP/M	B-Application
to	O
adapt	O
for	O
different	O
hardware	O
platforms	O
.	O
</s>
<s>
To	O
this	O
end	O
,	O
MS-DOS	B-Application
was	O
designed	O
with	O
a	O
modular	O
structure	O
with	O
internal	O
device	O
drivers	O
(	O
the	O
DOS	B-Device
BIOS	O
)	O
,	O
minimally	O
for	O
primary	O
disk	O
drives	O
and	O
the	O
console	O
,	O
integrated	O
with	O
the	O
kernel	O
and	O
loaded	O
by	O
the	O
boot	O
loader	O
,	O
and	O
installable	O
device	O
drivers	O
for	O
other	O
devices	O
loaded	O
and	O
integrated	O
at	O
boot	O
time	O
.	O
</s>
<s>
The	O
OEM	O
would	O
use	O
a	O
development	O
kit	O
provided	O
by	O
Microsoft	O
to	O
build	O
a	O
version	O
of	O
MS-DOS	B-Application
with	O
their	O
basic	O
I/O	O
drivers	O
and	O
a	O
standard	O
Microsoft	O
kernel	O
,	O
which	O
they	O
would	O
typically	O
supply	O
on	O
disk	O
to	O
end	O
users	O
along	O
with	O
the	O
hardware	O
.	O
</s>
<s>
Thus	O
,	O
there	O
were	O
many	O
different	O
versions	O
of	O
"	O
MS-DOS	B-Application
"	O
for	O
different	O
hardware	O
,	O
and	O
there	O
is	O
a	O
major	O
distinction	O
between	O
an	O
IBM-compatible	O
(	O
or	O
ISA	O
)	O
machine	O
and	O
an	O
MS-DOS	B-Application
 [ compatible ] 	O
machine	O
.	O
</s>
<s>
Some	O
machines	O
,	O
like	O
the	O
Tandy	B-Device
2000	I-Device
,	O
were	O
MS-DOS	B-Application
compatible	O
but	O
not	O
IBM-compatible	O
,	O
so	O
they	O
could	O
run	O
software	O
written	O
exclusively	O
for	O
MS-DOS	B-Application
without	O
dependence	O
on	O
the	O
peripheral	O
hardware	O
of	O
the	O
IBM	B-Device
PC	I-Device
architecture	O
.	O
</s>
<s>
This	O
design	O
would	O
have	O
worked	O
well	O
for	O
compatibility	O
,	O
if	O
application	B-Application
programs	I-Application
had	O
only	O
used	O
MS-DOS	B-Application
services	O
to	O
perform	O
device	O
I/O	O
,	O
and	O
indeed	O
the	O
same	O
design	O
philosophy	O
is	O
embodied	O
in	O
Windows	B-Device
NT	I-Device
(	O
see	O
Hardware	B-Operating_System
Abstraction	I-Operating_System
Layer	I-Operating_System
)	O
.	O
</s>
<s>
However	O
,	O
in	O
MS-DOS	B-Application
'	O
s	O
early	O
days	O
,	O
the	O
greater	O
speed	O
attainable	O
by	O
programs	O
through	O
direct	O
control	O
of	O
hardware	O
was	O
of	O
particular	O
importance	O
,	O
especially	O
for	O
games	O
,	O
which	O
often	O
pushed	O
the	O
limits	O
of	O
their	O
contemporary	O
hardware	O
.	O
</s>
<s>
Very	O
soon	O
an	O
IBM-compatible	O
architecture	O
became	O
the	O
goal	O
,	O
and	O
before	O
long	O
all	O
8086-family	O
computers	O
closely	O
emulated	O
IBM	O
's	O
hardware	O
,	O
and	O
only	O
a	O
single	O
version	O
of	O
MS-DOS	B-Application
for	O
a	O
fixed	O
hardware	O
platform	O
was	O
needed	O
for	O
the	O
market	O
.	O
</s>
<s>
This	O
version	O
is	O
the	O
version	O
of	O
MS-DOS	B-Application
that	O
is	O
discussed	O
here	O
,	O
as	O
the	O
dozens	O
of	O
other	O
OEM	O
versions	O
of	O
"	O
MS-DOS	B-Application
"	O
were	O
only	O
relevant	O
to	O
the	O
systems	O
they	O
were	O
designed	O
for	O
,	O
and	O
in	O
any	O
case	O
were	O
very	O
similar	O
in	O
function	O
and	O
capability	O
to	O
some	O
standard	O
version	O
for	O
the	O
IBM	B-Device
PC	I-Device
—	O
often	O
the	O
same-numbered	O
version	O
,	O
but	O
not	O
always	O
,	O
since	O
some	O
OEMs	O
used	O
their	O
own	O
proprietary	B-Application
version	O
numbering	O
schemes	O
(	O
e.g.	O
</s>
<s>
labeling	O
later	O
releases	O
of	O
MS-DOS	B-Application
1.x	O
as	O
2.0	O
or	O
vice	O
versa	O
)	O
—	O
with	O
a	O
few	O
notable	O
exceptions	O
.	O
</s>
<s>
Microsoft	O
omitted	O
multi-user	B-Operating_System
support	O
from	O
MS-DOS	B-Application
because	O
Microsoft	O
's	O
Unix-based	O
operating	B-General_Concept
system	I-General_Concept
,	O
Xenix	B-Application
,	O
was	O
fully	O
multi-user	B-Operating_System
.	O
</s>
<s>
The	O
company	O
planned	O
,	O
over	O
time	O
,	O
to	O
improve	O
MS-DOS	B-Application
so	O
it	O
would	O
be	O
almost	O
indistinguishable	O
from	O
single-user	B-Operating_System
Xenix	B-Application
,	O
or	O
XEDOS	B-Application
,	O
which	O
would	O
also	O
run	O
on	O
the	O
Motorola	B-Device
68000	I-Device
,	O
Zilog	B-Device
Z8000	I-Device
,	O
and	O
the	O
LSI-11	O
;	O
they	O
would	O
be	O
upwardly	B-General_Concept
compatible	I-General_Concept
with	O
Xenix	B-Application
,	O
which	O
Byte	B-Application
in	O
1983	O
described	O
as	O
"	O
the	O
multi-user	B-Operating_System
MS-DOS	B-Application
of	O
the	O
future	O
"	O
.	O
</s>
<s>
Microsoft	O
advertised	O
MS-DOS	B-Application
and	O
Xenix	B-Application
together	O
,	O
listing	O
the	O
shared	O
features	O
of	O
its	O
"	O
single-user	B-Operating_System
OS	O
"	O
and	O
"	O
the	O
multi-user	B-Operating_System
,	O
multi-tasking	B-Operating_System
,	O
UNIX-derived	O
operating	B-General_Concept
system	I-General_Concept
"	O
,	O
and	O
promising	O
easy	O
porting	O
between	O
them	O
.	O
</s>
<s>
After	O
the	O
breakup	O
of	O
the	O
Bell	O
System	O
,	O
however	O
,	O
AT&T	O
Computer	O
Systems	O
started	O
selling	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
.	O
Believing	O
that	O
it	O
could	O
not	O
compete	O
with	O
AT&T	O
in	O
the	O
Unix	B-Application
market	O
,	O
Microsoft	O
abandoned	O
Xenix	B-Application
,	O
and	O
in	O
1987	O
transferred	O
ownership	O
of	O
Xenix	B-Application
to	O
the	O
Santa	O
Cruz	O
Operation	O
(	O
SCO	O
)	O
.	O
</s>
<s>
On	O
March	O
25	O
,	O
2014	O
,	O
Microsoft	O
made	O
the	O
code	O
to	O
SCP	B-Operating_System
MS-DOS	I-Operating_System
1.25	I-Operating_System
and	O
a	O
mixture	O
of	O
Altos	O
MS-DOS	B-Application
2.11	O
and	O
TeleVideo	O
PC	B-Operating_System
DOS	I-Operating_System
2.11	O
available	O
to	O
the	O
public	O
under	O
the	O
Microsoft	B-License
Research	I-License
License	I-License
Agreement	I-License
,	O
which	O
makes	O
the	O
code	O
source-available	B-License
,	O
but	O
not	O
open	B-Application
source	I-Application
as	O
defined	O
by	O
Open	B-Application
Source	I-Application
Initiative	O
or	O
Free	B-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
standards	O
.	O
</s>
<s>
Microsoft	O
would	O
later	O
re-license	O
the	O
code	O
under	O
the	B-License
MIT	I-License
License	I-License
on	O
September	O
28	O
,	O
2018	O
,	O
making	O
these	O
versions	O
free	B-Application
software	I-Application
.	O
</s>
<s>
As	O
an	O
April	O
Fool	O
's	O
Day	O
joke	O
in	O
2015	O
,	O
Microsoft	O
Mobile	O
launched	O
a	O
Windows	B-Protocol
Phone	I-Protocol
application	O
called	O
MS-DOS	B-Application
Mobile	O
which	O
was	O
presented	O
as	O
a	O
new	O
mobile	O
operating	B-General_Concept
system	I-General_Concept
and	O
worked	O
similar	O
to	O
MS-DOS	B-Application
.	O
</s>
<s>
Microsoft	O
licensed	O
or	O
released	O
versions	O
of	O
MS-DOS	B-Application
under	O
different	O
names	O
like	O
Lifeboat	O
Associates	O
"	O
Software	B-Architecture
Bus	I-Architecture
86	O
"	O
a.k.a.	O
</s>
<s>
SB-DOS	B-Architecture
,	O
COMPAQ-DOS	O
,	O
NCR-DOS	O
or	O
Z-DOS	B-Operating_System
before	O
it	O
eventually	O
enforced	O
the	O
MS-DOS	B-Application
name	O
for	O
all	O
versions	O
but	O
the	O
IBM	O
one	O
,	O
which	O
was	O
originally	O
called	O
"	O
IBM	B-Operating_System
Personal	I-Operating_System
Computer	I-Operating_System
DOS	I-Operating_System
"	O
,	O
later	O
shortened	O
to	O
IBM	B-Device
PC	I-Device
DOS	B-Device
.	O
</s>
<s>
(	O
Competitors	O
released	O
compatible	O
DOS	B-Device
systems	O
such	O
as	O
DR	O
DOS	B-Device
and	O
PTS-DOS	B-Operating_System
that	O
could	O
also	O
run	O
MS-DOS	B-Application
applications	B-Application
.	O
)	O
</s>
<s>
In	O
the	O
former	O
Eastern	O
bloc	O
,	O
MS-DOS	B-Application
derivatives	O
named	O
DCP	O
(	O
)	O
3.20	O
and	O
3.30	O
(	O
DCP1700	O
,	O
DCP3.3	O
)	O
and	O
WDOS	O
existed	O
in	O
the	O
late	O
1980s	O
.	O
</s>
<s>
The	O
following	O
versions	O
of	O
MS-DOS	B-Application
were	O
released	O
to	O
the	O
public	O
:	O
</s>
<s>
Support	O
for	O
IBM	O
's	O
XT	O
10	O
MB	O
hard	O
disk	O
drives	O
,	O
support	O
up	O
to	O
16	O
MB	O
or	O
32	O
MB	O
FAT12	B-Application
formatted	O
hard	O
disk	O
drives	O
depending	O
on	O
the	O
formatting	O
tool	O
shipped	O
by	O
OEMs	O
,	O
user	O
installable	O
device	O
drivers	O
,	O
tree-structure	O
filing	O
system	O
,	O
Unix-like	O
inheritable	O
redirectable	O
file	O
handles	O
,	O
non-multitasking	O
child	O
processes	O
an	O
improved	O
Terminate	O
and	O
Stay	O
Resident	O
(	O
TSR	O
)	O
API	B-Application
,	O
environment	O
variables	O
,	O
device	O
driver	O
support	O
,	O
FOR	O
and	O
GOTO	O
loops	O
in	O
batch	O
files	O
,	O
ANSI.SYS	O
.	O
</s>
<s>
Version	O
3.2	O
(	O
OEM	O
)	O
–	O
First	O
version	O
to	O
support	O
3.5-inch	O
,	O
720	O
KB	O
floppy	B-Device
drives	I-Device
and	O
diskettes	B-Device
and	O
XCOPY	O
.	O
</s>
<s>
MS-DOS	B-Application
4.0	I-Application
(	O
multitasking	B-Operating_System
)	O
and	O
MS-DOS	O
4.1	O
A	O
separate	O
branch	O
of	O
development	O
with	O
additional	O
multitasking	B-Operating_System
features	O
,	O
released	O
between	O
3.2	O
and	O
3.3	O
,	O
and	O
later	O
abandoned	O
.	O
</s>
<s>
Version	O
4.01	O
(	O
OEM	O
)	O
–	O
Microsoft	O
rewritten	O
Version	O
4.00	O
released	O
under	O
MS-DOS	B-Application
label	O
but	O
not	O
IBM	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
.	O
</s>
<s>
Version	O
5.0	O
(	O
Retail	O
)	O
–	O
includes	O
a	O
full-screen	B-Application
text	I-Application
editor	I-Application
.	O
</s>
<s>
First	O
version	O
to	O
support	O
3.5-inch	O
,	O
2.88	O
MB	O
floppy	B-Device
drives	I-Device
and	O
diskettes	B-Device
.	O
</s>
<s>
The	O
SHARE	B-Application
command	O
was	O
not	O
needed	O
anymore	O
for	O
old	O
DOS1.x	O
style	O
FCB	B-Operating_System
file	O
API	B-Application
to	O
partitions	O
over	O
32	O
MB	O
.	O
</s>
<s>
First	O
version	O
to	O
get	O
the	O
HIMEM.SYS	O
driver	O
and	O
load	O
portions	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
into	O
the	O
upper	B-Device
memory	I-Device
area	I-Device
and	O
high	B-Device
memory	I-Device
area	I-Device
.	O
</s>
<s>
Support	O
up	O
to	O
four	O
DOS	B-Device
primary	O
partitions	O
although	O
FDISK	B-Application
cannot	O
create	O
more	O
than	O
one	O
.	O
</s>
<s>
Version	O
6.0	O
(	O
Retail	O
)	O
–	O
Online	O
help	O
through	O
QBASIC	B-Language
.	O
</s>
<s>
Disk	B-General_Concept
compression	I-General_Concept
,	O
upper	B-Device
memory	I-Device
optimization	O
and	O
antivirus	O
included	O
.	O
</s>
<s>
Version	O
6.2	O
–	O
SCANDISK	O
as	O
replacement	O
for	O
CHKDSK	B-Device
.	O
</s>
<s>
Fix	O
serious	O
bugs	O
in	O
DBLSPACE	B-General_Concept
.	O
</s>
<s>
Version	O
6.21	O
(	O
Retail	O
)	O
–	O
Stacker-infringing	O
DBLSPACE	B-General_Concept
removed	O
.	O
</s>
<s>
Version	O
6.22	O
(	O
Retail	O
)	O
–	O
New	O
DRVSPACE	B-General_Concept
compression	O
.	O
</s>
<s>
MS-DOS	B-Application
7.0	O
was	O
included	O
in	O
Windows	B-Application
95	I-Application
's	O
first	O
retail	O
release	O
.	O
</s>
<s>
It	O
contains	O
support	O
for	O
VFAT	B-Application
long	O
file	O
names	O
when	O
run	O
in	O
a	O
Windows	O
Virtual	B-Application
8086	I-Application
box	O
or	O
with	O
an	O
LFN	O
driver	O
such	O
as	O
DOSLFN	O
.	O
</s>
<s>
JO.SYS	O
is	O
an	O
alternative	O
filename	O
of	O
the	O
IO.SYS	O
kernel	O
file	O
and	O
used	O
as	O
such	O
for	O
"	O
special	O
purposes	O
"	O
.	O
</s>
<s>
JO.SYS	O
allows	O
booting	O
from	O
either	O
CD-ROM	O
drive	O
or	O
hard	O
disk	O
.	O
</s>
<s>
The	O
VER	B-Device
internal	O
command	O
reports	O
the	O
Windows	O
version	O
4.00.950	O
,	O
applications	B-Application
through	O
the	O
MS-DOS	B-Application
API	I-Application
would	O
be	O
reported	O
a	O
version	O
number	O
of	O
7.00	O
.	O
</s>
<s>
MS-DOS	B-Application
7.1	O
was	O
included	O
in	O
Windows	B-Application
95	I-Application
's	O
OEM	O
Service	O
Release	O
2	O
through	O
Windows	B-Device
98	I-Device
Second	O
Edition	O
.	O
</s>
<s>
It	O
added	O
support	O
for	O
the	O
FAT32	B-Application
file	O
system	O
and	O
logical	B-Device
block	I-Device
addressing	I-Device
(	O
LBA	O
)	O
,	O
and	O
was	O
the	O
last	O
version	O
that	O
could	O
boot	O
to	O
the	O
command	B-Application
line	I-Application
from	O
a	O
hard	O
disk	O
.	O
</s>
<s>
The	O
VER	B-Device
internal	O
command	O
reports	O
the	O
Windows	O
version	O
4.00.1111	O
,	O
4.10.1998	O
,	O
or	O
4.10.2222	O
depending	O
on	O
the	O
version	O
of	O
Windows	O
,	O
while	O
applications	B-Application
through	O
the	O
API	B-Application
would	O
report	O
version	O
7.10	O
.	O
</s>
<s>
MS-DOS	B-Application
8.0	O
was	O
included	O
in	O
Windows	B-Device
Me	I-Device
,	O
the	O
last	O
version	O
based	O
on	O
MS-DOS	B-Application
,	O
and	O
DOS	B-Device
mode	O
was	O
significantly	O
altered	O
in	O
this	O
release	O
.	O
</s>
<s>
Booting	O
from	O
the	O
hard	O
disk	O
to	O
a	O
command	B-Application
line	I-Application
only	O
was	O
no	O
longer	O
permitted	O
,	O
AUTOEXEC.BAT	O
and	O
CONFIG.SYS	B-Device
files	O
were	O
no	O
longer	O
loaded	O
nor	O
parsed	O
before	O
loading	O
the	O
Windows	O
GUI	B-Application
;	O
booting	O
from	O
floppy	B-Device
disk	I-Device
was	O
still	O
permitted	O
to	O
allow	O
for	O
emergency	O
recovery	O
and	O
this	O
version	O
is	O
included	O
in	O
Windows	B-Application
XP	I-Application
and	O
later	O
versions	O
for	O
creating	O
MS-DOS	B-Application
Startup	O
Disks	O
.	O
</s>
<s>
The	O
VER	B-Device
internal	O
command	O
reports	O
the	O
Windows	O
version	O
4.90.3000	O
,	O
or	O
5.1	O
when	O
created	O
from	O
newer	O
versions	O
of	O
Windows	O
.	O
</s>
<s>
Applications	B-Application
requesting	O
the	O
version	O
through	O
the	O
API	B-Application
would	O
report	O
version	O
8.00	O
.	O
</s>
<s>
Microsoft	O
DOS	B-Device
was	O
released	O
through	O
the	O
OEM	O
channel	O
,	O
until	O
Digital	O
Research	O
released	O
DR-DOS	B-Application
5.0	O
as	O
a	O
retail	O
upgrade	O
.	O
</s>
<s>
With	O
PC	O
DOS	B-Device
5.00.1	O
,	O
the	O
IBM	O
–	O
Microsoft	O
agreement	O
started	O
to	O
end	O
,	O
and	O
IBM	O
entered	O
the	O
retail	O
DOS	B-Device
market	O
with	O
IBM	B-Operating_System
DOS	I-Operating_System
5.00.1	O
,	O
5.02	O
,	O
6.00	O
and	O
PCDOS	B-Operating_System
6.1	O
,	O
6.3	O
,	O
7	O
,	O
2000	B-Application
and	O
7.1	O
.	O
</s>
<s>
Localized	O
versions	O
of	O
MS-DOS	B-Application
existed	O
for	O
different	O
markets	O
.	O
</s>
<s>
While	O
Western	O
issues	O
of	O
MS-DOS	B-Application
evolved	O
around	O
the	O
same	O
set	O
of	O
tools	O
and	O
drivers	O
just	O
with	O
localized	O
message	O
languages	O
and	O
differing	O
sets	O
of	O
supported	O
codepages	B-Device
and	O
keyboard	O
layouts	O
,	O
some	O
language	O
versions	O
were	O
considerably	O
different	O
from	O
Western	O
issues	O
and	O
were	O
adapted	O
to	O
run	O
on	O
localized	O
PC	O
hardware	O
with	O
additional	O
BIOS	O
services	O
not	O
available	O
in	O
Western	O
PCs	B-Device
,	O
support	O
multiple	O
hardware	O
codepages	B-Device
for	O
displays	O
and	O
printers	O
,	O
support	O
DBCS	O
,	O
alternative	O
input	O
methods	O
and	O
graphics	O
output	O
.	O
</s>
<s>
Affected	O
issues	O
include	O
Japanese	O
(	O
DOS/V	B-Application
)	O
,	O
Korean	O
,	O
Arabic	O
(	O
ADOS	O
3.3/5.0	O
)	O
,	O
Hebrew	O
(	O
HDOS	O
3.3/5.0	O
)	O
,	O
Russian	O
(	O
RDOS	O
4.01/5.0	O
)	O
as	O
well	O
as	O
some	O
other	O
Eastern	O
European	O
versions	O
of	O
DOS	B-Device
.	O
</s>
<s>
On	O
microcomputers	O
based	O
on	O
the	O
Intel	B-General_Concept
8086	I-General_Concept
and	O
8088	B-Device
processors	O
,	O
including	O
the	O
IBM	B-Device
PC	I-Device
and	O
clones	O
,	O
the	O
initial	O
competition	O
to	O
the	O
PC	O
DOS/MS	O
-DOS	O
line	O
came	O
from	O
Digital	O
Research	O
,	O
whose	O
CP/M	B-Application
operating	I-Application
system	I-Application
had	O
inspired	O
MS-DOS	B-Application
.	O
</s>
<s>
In	O
fact	O
,	O
there	O
remains	O
controversy	O
as	O
to	O
whether	O
QDOS	B-Operating_System
was	O
more	O
or	O
less	O
plagiarized	O
from	O
early	O
versions	O
of	O
CP/M	B-Application
code	O
.	O
</s>
<s>
Digital	O
Research	O
released	O
CP/M	B-Operating_System
-86	I-Operating_System
a	O
few	O
months	O
after	O
MS-DOS	B-Application
,	O
and	O
it	O
was	O
offered	O
as	O
an	O
alternative	O
to	O
MS-DOS	B-Application
and	O
Microsoft	O
's	O
licensing	O
requirements	O
,	O
but	O
at	O
a	O
higher	O
price	O
.	O
</s>
<s>
Executable	B-Application
programs	I-Application
for	O
CP/M	B-Operating_System
-86	I-Operating_System
and	O
MS-DOS	B-Application
were	O
not	O
interchangeable	O
with	O
each	O
other	O
;	O
many	O
applications	B-Application
were	O
sold	O
in	O
both	O
MS-DOS	B-Application
and	O
CP/M	B-Operating_System
-86	I-Operating_System
versions	O
until	O
MS-DOS	B-Application
became	O
preponderant	O
(	O
later	O
Digital	O
Research	O
operating	B-General_Concept
systems	I-General_Concept
could	O
run	O
both	O
MS-DOS	B-Application
and	O
CP/M	B-Operating_System
-86	I-Operating_System
software	O
)	O
.	O
</s>
<s>
MS-DOS	B-Application
originally	O
supported	O
the	O
simple	O
.COM	O
,	O
which	O
was	O
modeled	O
after	O
a	O
similar	O
but	O
binary-incompatible	O
format	O
known	O
from	O
CP/M	B-Application
-80	I-Application
.	O
</s>
<s>
CP/M	B-Operating_System
-86	I-Operating_System
instead	O
supported	O
a	O
relocatable	B-Library
format	O
using	O
the	O
file	O
extension	O
.CMD	O
to	O
avoid	O
name	O
conflicts	O
with	O
CP/M	B-Application
-80	I-Application
and	O
MS-DOS	B-Application
.COM	O
files	O
.	O
</s>
<s>
MS-DOS	B-Application
version	O
1.0	O
added	O
a	O
more	O
advanced	O
relocatable	B-Library
.EXE	O
executable	B-Application
file	I-Application
format	I-Application
.	O
</s>
<s>
Most	O
of	O
the	O
machines	O
in	O
the	O
early	O
days	O
of	O
MS-DOS	B-Application
had	O
differing	O
system	O
architectures	O
and	O
there	O
was	O
a	O
certain	O
degree	O
of	O
incompatibility	O
,	O
and	O
subsequently	O
vendor	O
lock-in	O
.	O
</s>
<s>
Users	O
who	O
began	O
using	O
MS-DOS	B-Application
with	O
their	O
machines	O
were	O
compelled	O
to	O
continue	O
using	O
the	O
version	O
customized	O
for	O
their	O
hardware	O
,	O
or	O
face	O
trying	O
to	O
get	O
all	O
of	O
their	O
proprietary	B-Application
hardware	O
and	O
software	O
to	O
work	O
with	O
the	O
new	O
system	O
.	O
</s>
<s>
In	O
the	O
business	O
world	O
the	O
808x-based	O
machines	O
that	O
MS-DOS	B-Application
was	O
tied	O
to	O
faced	O
competition	O
from	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
which	O
ran	O
on	O
many	O
different	O
hardware	O
architectures	O
.	O
</s>
<s>
Microsoft	O
itself	O
sold	O
a	O
version	O
of	O
Unix	B-Application
for	O
the	O
PC	O
called	O
Xenix	B-Application
.	O
</s>
<s>
In	O
the	O
emerging	O
world	O
of	O
home	O
users	O
,	O
a	O
variety	O
of	O
other	O
computers	O
based	O
on	O
various	O
other	O
processors	O
were	O
in	O
serious	O
competition	O
with	O
the	O
IBM	B-Device
PC	I-Device
:	O
the	O
Apple	B-Device
II	I-Device
,	O
early	O
Apple	B-Device
Macintosh	I-Device
,	O
the	O
Commodore	O
64	O
and	O
others	O
did	O
not	O
use	O
the	O
808x	O
processor	O
;	O
many	O
808x	O
machines	O
of	O
different	O
architectures	O
used	O
custom	O
versions	O
of	O
MS-DOS	B-Application
.	O
</s>
<s>
In	O
time	O
the	O
IBM	B-Device
PC	I-Device
hardware	O
configuration	O
became	O
dominant	O
in	O
the	O
808x	O
market	O
as	O
software	O
written	O
to	O
communicate	O
directly	O
with	O
the	O
PC	O
hardware	O
without	O
using	O
standard	O
operating	B-General_Concept
system	I-General_Concept
calls	O
ran	O
much	O
faster	O
,	O
but	O
on	O
true	O
PC-compatibles	O
only	O
.	O
</s>
<s>
Non-PC-compatible	O
808x	O
machines	O
were	O
too	O
small	O
a	O
market	O
to	O
have	O
fast	O
software	O
written	O
for	O
them	O
alone	O
,	O
and	O
the	O
market	O
remained	O
open	O
only	O
for	O
IBM	B-Device
PCs	I-Device
and	O
machines	O
that	O
closely	O
imitated	O
their	O
architecture	O
,	O
all	O
running	O
either	O
a	O
single	O
version	O
of	O
MS-DOS	B-Application
compatible	O
only	O
with	O
PCs	B-Device
,	O
or	O
the	O
equivalent	O
IBM	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
.	O
</s>
<s>
Most	O
clones	O
cost	O
much	O
less	O
than	O
IBM-branded	O
machines	O
of	O
similar	O
performance	O
,	O
and	O
became	O
widely	O
used	O
by	O
home	O
users	O
,	O
while	O
IBM	B-Device
PCs	I-Device
had	O
a	O
large	O
share	B-Application
of	O
the	O
business	O
computer	O
market	O
.	O
</s>
<s>
Microsoft	O
and	O
IBM	O
together	O
began	O
what	O
was	O
intended	O
as	O
the	O
follow-on	O
to	O
MS-DOS/PC	O
DOS	O
,	O
called	O
OS/2	B-Application
.	O
</s>
<s>
When	O
OS/2	B-Application
was	O
released	O
in	O
1987	O
,	O
Microsoft	O
began	O
an	O
advertising	O
campaign	O
announcing	O
that	O
"	O
DOS	B-Device
is	O
Dead	O
"	O
and	O
stating	O
that	O
version	O
4	O
was	O
the	O
last	O
full	O
release	O
.	O
</s>
<s>
OS/2	B-Application
was	O
designed	O
for	O
efficient	O
multi-tasking	B-Operating_System
and	O
offered	O
a	O
number	O
of	O
advanced	O
features	O
that	O
had	O
been	O
designed	O
together	O
with	O
similar	O
look	B-Application
and	I-Application
feel	I-Application
;	O
it	O
was	O
seen	O
as	O
the	O
legitimate	O
heir	O
to	O
the	O
"	O
kludgy	O
"	O
DOS	B-Device
platform	O
.	O
</s>
<s>
MS-DOS	B-Application
had	O
grown	O
in	O
spurts	O
,	O
with	O
many	O
significant	O
features	O
being	O
taken	O
or	O
duplicated	O
from	O
Microsoft	O
's	O
other	O
products	O
and	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
MS-DOS	B-Application
also	O
grew	O
by	O
incorporating	O
,	O
by	O
direct	O
licensing	O
or	O
feature	O
duplicating	O
,	O
the	O
functionality	O
of	O
tools	O
and	O
utilities	O
developed	O
by	O
independent	O
companies	O
,	O
such	O
as	O
Norton	B-Application
Utilities	I-Application
,	O
PC	B-Application
Tools	I-Application
(	O
Microsoft	B-Application
Anti-Virus	I-Application
)	O
,	O
QEMM	B-Device
expanded	B-Device
memory	I-Device
manager	O
,	O
Stacker	B-Algorithm
disk	B-General_Concept
compression	I-General_Concept
,	O
and	O
others	O
.	O
</s>
<s>
During	O
the	O
period	O
when	O
Digital	O
Research	O
was	O
competing	O
in	O
the	O
operating	B-General_Concept
system	I-General_Concept
market	O
some	O
computers	O
,	O
like	O
the	O
Amstrad	O
PC1512	O
,	O
were	O
sold	O
with	O
floppy	B-Device
disks	I-Device
for	O
two	O
operating	B-General_Concept
systems	I-General_Concept
(	O
only	O
one	O
of	O
which	O
could	O
be	O
used	O
at	O
a	O
time	O
)	O
,	O
MS-DOS	B-Application
and	O
CP/M	B-Operating_System
-86	I-Operating_System
or	O
a	O
derivative	O
of	O
it	O
.	O
</s>
<s>
Digital	O
Research	O
produced	O
DOS	B-Operating_System
Plus	I-Operating_System
,	O
which	O
was	O
compatible	O
with	O
MS-DOS	B-Application
2.11	O
,	O
supported	O
CP/M	B-Operating_System
-86	I-Operating_System
programs	O
,	O
had	O
additional	O
features	O
including	O
multi-tasking	B-Operating_System
,	O
and	O
could	O
read	O
and	O
write	O
disks	O
in	O
CP/M	B-Application
and	O
MS-DOS	B-Application
format	O
.	O
</s>
<s>
While	O
OS/2	B-Application
was	O
under	O
protracted	O
development	O
,	O
Digital	O
Research	O
released	O
the	O
MS-DOS	B-Application
compatible	O
DR	B-Application
DOS	I-Application
5.0	O
,	O
which	O
included	O
features	O
only	O
available	O
as	O
third-party	O
add-ons	O
for	O
MS-DOS	B-Application
.	O
</s>
<s>
Unwilling	O
to	O
lose	O
any	O
portion	O
of	O
the	O
market	O
,	O
Microsoft	O
responded	O
by	O
announcing	O
the	O
"	O
pending	O
"	O
release	O
of	O
MS-DOS	B-Application
5.0	O
in	O
May	O
1990	O
.	O
</s>
<s>
This	O
effectively	O
killed	O
most	O
DR	B-Application
DOS	I-Application
sales	O
until	O
the	O
actual	O
release	O
of	O
MS-DOS	B-Application
5.0	O
in	O
June	O
1991	O
.	O
</s>
<s>
Digital	O
Research	O
brought	O
out	O
DR	B-Application
DOS	I-Application
6.0	O
,	O
which	O
sold	O
well	O
until	O
the	O
"	O
pre-announcement	O
"	O
of	O
MS-DOS	B-Application
6.0	O
again	O
stifled	O
the	O
sales	O
of	O
DR	B-Application
DOS	I-Application
.	O
</s>
<s>
Microsoft	O
had	O
been	O
accused	O
of	O
carefully	O
orchestrating	O
leaks	O
about	O
future	O
versions	O
of	O
MS-DOS	B-Application
in	O
an	O
attempt	O
to	O
create	O
what	O
in	O
the	O
industry	O
is	O
called	O
FUD	O
(	O
fear	O
,	O
uncertainty	O
,	O
and	O
doubt	O
)	O
regarding	O
DR	B-Application
DOS	I-Application
.	O
</s>
<s>
For	O
example	O
,	O
in	O
October	O
1990	O
,	O
shortly	O
after	O
the	O
release	O
of	O
DR	B-Application
DOS	I-Application
5.0	O
,	O
and	O
long	O
before	O
the	O
eventual	O
June	O
1991	O
release	O
of	O
MS-DOS	B-Application
5.0	O
,	O
stories	O
on	O
feature	O
enhancements	O
in	O
MS-DOS	B-Application
started	O
to	O
appear	O
in	O
InfoWorld	O
and	O
PC	O
Week	O
.	O
</s>
<s>
Brad	O
Silverberg	O
,	O
then	O
Vice	O
President	O
of	O
Systems	O
Software	O
at	O
Microsoft	O
and	O
general	O
manager	O
of	O
its	O
Windows	O
and	O
MS-DOS	B-Application
Business	O
Unit	O
,	O
wrote	O
a	O
forceful	O
letter	O
to	O
PC	O
Week	O
(	O
November	O
5	O
,	O
1990	O
)	O
,	O
denying	O
that	O
Microsoft	O
was	O
engaged	O
in	O
FUD	O
tactics	O
(	O
"	O
to	O
serve	O
our	O
customers	O
better	O
,	O
we	O
decided	O
to	O
be	O
more	O
forthcoming	O
about	O
version	O
5.0	O
"	O
)	O
and	O
denying	O
that	O
Microsoft	O
copied	O
features	O
from	O
DR	B-Application
DOS	I-Application
:	O
</s>
<s>
"	O
The	O
feature	O
enhancements	O
of	O
MS-DOS	B-Application
version	O
5.0	O
were	O
decided	O
and	O
development	O
was	O
begun	O
long	O
before	O
we	O
heard	O
about	O
DR	B-Application
DOS	I-Application
5.0	O
.	O
</s>
<s>
With	O
50	O
million	O
MS-DOS	B-Application
users	O
,	O
it	O
should	O
n't	O
be	O
surprising	O
that	O
DRI	O
has	O
heard	O
some	O
of	O
the	O
same	O
requests	O
from	O
customers	O
that	O
we	O
have.	O
"	O
</s>
<s>
(	O
xviii+856+vi	O
pages	O
,	O
3.5	B-Device
"	I-Device
-floppy	O
)	O
Errata	O
:	O
</s>
<s>
The	O
pact	O
between	O
Microsoft	O
and	O
IBM	O
to	O
promote	O
OS/2	B-Application
began	O
to	O
fall	O
apart	O
in	O
1990	O
when	O
Windows	B-Application
3.0	I-Application
became	O
a	O
marketplace	O
success	O
.	O
</s>
<s>
Many	O
of	O
Microsoft	O
's	O
further	O
contributions	O
to	O
OS/2	B-Application
also	O
went	O
into	O
creating	O
a	O
third	O
GUI	B-Application
replacement	O
for	O
DOS	B-Device
,	O
Windows	B-Device
NT	I-Device
.	O
</s>
<s>
IBM	O
,	O
which	O
had	O
already	O
been	O
developing	O
the	O
next	O
version	O
of	O
OS/2	B-Application
,	O
carried	O
on	O
development	O
of	O
the	O
platform	O
without	O
Microsoft	O
and	O
sold	O
it	O
as	O
the	O
alternative	O
to	O
DOS	B-Device
and	O
Windows	O
.	O
</s>
<s>
As	O
a	O
response	O
to	O
Digital	O
Research	O
's	O
DR	B-Application
DOS	I-Application
6.0	O
,	O
which	O
bundled	O
SuperStor	O
disk	B-General_Concept
compression	I-General_Concept
,	O
Microsoft	O
opened	O
negotiations	O
with	O
Stac	O
Electronics	O
,	O
vendor	O
of	O
the	O
most	O
popular	O
DOS	B-Device
disk	B-General_Concept
compression	I-General_Concept
tool	O
,	O
Stacker	B-Algorithm
.	O
</s>
<s>
In	O
the	O
due	O
diligence	O
process	O
,	O
Stac	O
engineers	O
had	O
shown	O
Microsoft	O
part	O
of	O
the	O
Stacker	B-Algorithm
source	O
code	O
.	O
</s>
<s>
Stac	O
was	O
unwilling	O
to	O
meet	O
Microsoft	O
's	O
terms	O
for	O
licensing	O
Stacker	B-Algorithm
and	O
withdrew	O
from	O
the	O
negotiations	O
.	O
</s>
<s>
Microsoft	O
chose	O
to	O
license	O
Vertisoft	O
's	O
DoubleDisk	O
,	O
using	O
it	O
as	O
the	O
core	O
for	O
its	O
DoubleSpace	B-General_Concept
disk	B-General_Concept
compression	I-General_Concept
.	O
</s>
<s>
MS-DOS	B-Application
6.0	O
and	O
6.20	O
were	O
released	O
in	O
1993	O
,	O
both	O
including	O
the	O
Microsoft	O
DoubleSpace	B-General_Concept
disk	B-General_Concept
compression	I-General_Concept
utility	O
program	O
.	O
</s>
<s>
Stac	O
successfully	O
sued	O
Microsoft	O
for	O
patent	O
infringement	O
regarding	O
the	O
compression	O
algorithm	O
used	O
in	O
DoubleSpace	B-General_Concept
.	O
</s>
<s>
This	O
resulted	O
in	O
the	O
1994	O
release	O
of	O
MS-DOS	B-Application
6.21	O
,	O
which	O
had	O
disk	B-General_Concept
compression	I-General_Concept
removed	O
.	O
</s>
<s>
Shortly	O
afterwards	O
came	O
version	O
6.22	O
,	O
with	O
a	O
new	O
version	O
of	O
the	O
disk	B-General_Concept
compression	I-General_Concept
system	O
,	O
DriveSpace	B-General_Concept
,	O
which	O
had	O
a	O
different	O
compression	O
algorithm	O
to	O
avoid	O
the	O
infringing	O
code	O
.	O
</s>
<s>
Prior	O
to	O
1995	O
,	O
Microsoft	O
licensed	O
MS-DOS	B-Application
(	O
and	O
Windows	O
)	O
to	O
computer	O
manufacturers	O
under	O
three	O
types	O
of	O
agreement	O
:	O
per-processor	O
(	O
a	O
fee	O
for	O
each	O
system	O
the	O
company	O
sold	O
)	O
,	O
per-system	O
(	O
a	O
fee	O
for	O
each	O
system	O
of	O
a	O
particular	O
model	O
)	O
,	O
or	O
per-copy	O
(	O
a	O
fee	O
for	O
each	O
copy	O
of	O
MS-DOS	B-Application
installed	O
)	O
.	O
</s>
<s>
This	O
arrangement	O
made	O
it	O
expensive	O
for	O
the	O
large	O
manufacturers	O
to	O
migrate	O
to	O
any	O
other	O
operating	B-General_Concept
system	I-General_Concept
,	O
such	O
as	O
DR	B-Application
DOS	I-Application
.	O
</s>
<s>
Microsoft	O
also	O
used	O
a	O
variety	O
of	O
tactics	O
in	O
MS-DOS	B-Application
and	O
several	O
of	O
their	O
applications	B-Application
and	O
development	O
tools	O
that	O
,	O
while	O
operating	O
perfectly	O
when	O
running	O
on	O
genuine	O
MS-DOS	B-Application
(	O
and	O
PC	B-Operating_System
DOS	I-Operating_System
)	O
,	O
would	O
break	O
when	O
run	O
on	O
another	O
vendor	O
's	O
implementation	O
of	O
DOS	B-Device
.	O
</s>
<s>
Microsoft	B-Language
's	I-Language
QuickPascal	I-Language
(	O
released	O
in	O
early	O
1989	O
)	O
was	O
the	O
first	O
MS	O
product	O
that	O
checked	O
for	O
MS-DOS	B-Application
by	O
modifying	O
the	O
program	O
's	O
Program	O
Segment	O
Prefix	O
using	O
undocumented	O
DOS	B-Device
functions	O
,	O
and	O
then	O
checked	O
whether	O
or	O
not	O
the	O
associated	O
value	O
changed	O
in	O
a	O
fixed	O
position	O
within	O
the	O
DOS	B-Device
data	O
segment	O
(	O
also	O
undocumented	O
)	O
.	O
</s>
<s>
This	O
check	O
also	O
made	O
it	O
into	O
later	O
MS	O
products	O
,	O
including	O
Microsoft	O
QuickC	B-Application
v2.5	O
,	O
Programmer	O
's	O
Workbench	O
and	O
Microsoft	O
C	B-Language
v6.0	O
.	O
</s>
<s>
It	O
was	O
XOR	O
encrypted	O
,	O
self-modifying	B-Application
,	O
and	O
deliberately	O
obfuscated	O
,	O
using	O
various	O
undocumented	O
DOS	B-Device
structures	O
and	O
functions	O
to	O
determine	O
whether	O
or	O
not	O
Windows	O
really	O
was	O
running	O
on	O
MS-DOS	B-Application
.	O
</s>
<s>
In	O
the	O
beta	O
versions	O
,	O
it	O
displayed	O
an	O
"	O
error	O
"	O
message	O
if	O
the	O
test	O
for	O
genuine	O
MS-DOS	B-Application
failed	O
,	O
prompting	O
the	O
user	O
to	O
abort	O
or	O
continue	O
,	O
with	O
abort	O
the	O
default	O
.	O
</s>
<s>
In	O
the	O
final	O
release	O
version	O
,	O
the	O
code	O
still	O
ran	O
,	O
but	O
the	O
message	O
and	O
prompt	O
were	O
disabled	O
by	O
an	O
added	O
flag	O
byte	B-Application
,	O
rendering	O
it	O
(	O
probably	O
)	O
ineffectual	O
.	O
</s>
<s>
Note	O
that	O
the	O
Windows	B-Application
3.0	I-Application
beta	O
code	O
only	O
gave	O
a	O
warning	O
that	O
Windows	O
would	O
not	O
operate	O
properly	O
on	O
a	O
"	O
foreign	O
"	O
OS	O
.	O
</s>
<s>
It	O
did	O
,	O
in	O
fact	O
,	O
run	O
just	O
fine	O
on	O
DR	B-Application
DOS	I-Application
6.0	O
.	O
</s>
<s>
Interrupt	O
routines	O
called	O
by	O
Windows	O
to	O
inform	O
MS-DOS	B-Application
that	O
Windows	O
is	O
starting/exiting	O
,	O
information	O
that	O
MS-DOS	B-Application
retained	O
in	O
an	O
IN_WINDOWS	O
flag	O
,	O
in	O
spite	O
of	O
the	O
fact	O
that	O
MS-DOS	B-Application
and	O
Windows	O
were	O
supposed	O
to	O
be	O
two	O
separate	O
products	O
.	O
</s>
<s>
All	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
have	O
had	O
an	O
MS-DOS	B-Application
or	O
MS-DOS-like	O
command-line	B-Application
interface	I-Application
called	O
MS-DOS	B-Operating_System
Prompt	I-Operating_System
which	O
redirected	O
input	O
to	O
MS-DOS	B-Application
and	O
output	O
from	O
MS-DOS	B-Application
to	O
the	O
MS-DOS	B-Operating_System
Prompt	I-Operating_System
,	O
or	O
,	O
in	O
later	O
versions	O
,	O
Command	B-Device
Prompt	I-Device
.	O
</s>
<s>
This	O
could	O
run	O
many	O
DOS	B-Device
and	O
variously	O
Win32	O
,	O
OS/2	B-Application
1.x	O
and	O
POSIX	O
command-line	B-Application
utilities	O
in	O
the	O
same	O
command-line	B-Application
session	O
,	O
allowing	O
piping	O
between	O
commands	O
.	O
</s>
<s>
The	O
user	O
interface	O
,	O
and	O
the	O
icon	O
up	O
to	O
Windows	B-Application
2000	I-Application
,	O
followed	O
the	O
native	O
MS-DOS	B-Application
interface	O
.	O
</s>
<s>
The	O
Command	B-Device
Prompt	I-Device
introduced	O
with	O
Windows	B-Device
NT	I-Device
is	O
not	O
actually	O
MS-DOS	B-Application
,	O
but	O
shares	O
some	O
commands	O
with	O
MS-DOS	B-Application
.	O
</s>
<s>
The	O
16-bit	B-Device
versions	O
of	O
Windows	O
(	O
up	O
to	O
3.11	O
)	O
ran	O
as	O
a	O
Graphical	B-Application
User	I-Application
Interface	I-Application
(	O
GUI	B-Application
)	O
on	O
top	O
of	O
MS-DOS	B-Application
.	O
</s>
<s>
With	O
Windows	B-Application
95	I-Application
,	O
98	B-Device
,	O
and	O
Me	B-Device
,	O
the	O
role	O
of	O
MS-DOS	B-Application
was	O
reduced	O
to	O
a	O
boot	O
loader	O
according	O
to	O
Microsoft	O
,	O
with	O
MS-DOS	B-Application
programs	O
running	O
in	O
a	O
virtual	O
DOS	B-Device
machine	O
within	O
32-bit	B-Application
Windows	I-Application
,	O
with	O
ability	O
to	O
boot	O
directly	O
into	O
MS-DOS	B-Application
retained	O
as	O
a	O
backward	O
compatibility	O
option	O
for	O
applications	B-Application
that	O
required	O
real	O
mode	O
access	O
to	O
the	O
hardware	O
,	O
which	O
was	O
generally	O
not	O
possible	O
within	O
Windows	O
.	O
</s>
<s>
The	O
command	B-Application
line	I-Application
accessed	O
the	O
DOS	B-Operating_System
command	B-Application
line	I-Application
(	O
usually	O
COMMAND.COM	B-Operating_System
)	O
through	O
a	O
Windows	O
module	O
(	O
WINOLDAP.MOD	O
)	O
.	O
</s>
<s>
Windows	O
NT-based	O
operating	B-General_Concept
systems	I-General_Concept
boot	O
through	O
a	O
kernel	O
whose	O
sole	O
purpose	O
is	O
to	O
load	O
Windows	O
.	O
</s>
<s>
One	O
cannot	O
run	O
Win32	O
applications	B-Application
in	O
the	O
loader	O
system	O
in	O
the	O
manner	O
that	O
OS/2	B-Application
,	O
UNIX	B-Application
or	O
consumer	O
versions	O
of	O
Windows	O
can	O
launch	O
character-mode	O
sessions	O
.	O
</s>
<s>
The	O
command	O
session	O
permits	O
running	O
various	O
supported	O
command-line	B-Application
utilities	O
from	O
Win32	O
,	O
MS-DOS	B-Application
,	O
OS/2	B-Application
1.x	O
and	O
POSIX	O
.	O
</s>
<s>
The	O
emulators	O
for	O
MS-DOS	B-Application
,	O
OS/2	B-Application
and	O
POSIX	O
use	O
the	O
host	O
's	O
window	O
in	O
the	O
same	O
way	O
that	O
Win16	O
applications	B-Application
use	O
the	O
Win32	O
explorer	O
.	O
</s>
<s>
The	O
MS-DOS	B-Application
emulation	O
takes	O
place	O
through	O
the	O
NTVDM	O
(	O
NT	O
Virtual	O
DOS	B-Device
Machine	O
)	O
.	O
</s>
<s>
This	O
is	O
a	O
modified	O
SoftPC	B-Device
(	O
a	O
former	O
product	O
similar	O
to	O
VirtualPC	B-Application
)	O
,	O
running	O
a	O
modified	O
MS-DOS	B-Application
5	O
(	O
NTIO.SYS	O
and	O
NTDOS.SYS	O
)	O
.	O
</s>
<s>
The	O
output	O
is	O
handled	O
by	O
the	O
console	O
DLLs	O
,	O
so	O
that	O
the	O
program	O
at	O
the	O
prompt	O
(	O
CMD.EXE	B-Device
,	O
4NT.EXE	O
,	O
TCC.EXE	O
)	O
,	O
can	O
see	O
the	O
output	O
.	O
</s>
<s>
64-bit	B-Device
Windows	O
has	O
neither	O
the	O
DOS	B-Device
emulation	O
,	O
nor	O
the	O
DOS	B-Operating_System
commands	I-Operating_System
EDIT	B-Application
,	O
DEBUG	B-Device
and	O
EDLIN	B-Application
that	O
come	O
with	O
32-bit	B-Application
Windows	I-Application
.	O
</s>
<s>
The	O
DOS	B-Device
version	O
returns	O
5.00	O
or	O
5.50	O
,	O
depending	O
on	O
which	O
API	B-Application
function	I-Application
is	O
used	O
to	O
determine	O
it	O
.	O
</s>
<s>
Utilities	O
from	O
MS-DOS	B-Application
5.00	O
run	O
in	O
this	O
emulation	O
without	O
modification	O
.	O
</s>
<s>
The	O
very	O
early	O
beta	O
programs	O
of	O
NT	O
show	O
MS-DOS	B-Application
30.00	O
,	O
but	O
programs	O
running	O
in	O
MS-DOS	B-Application
30.00	O
would	O
assume	O
that	O
OS/2	B-Application
was	O
in	O
control	O
.	O
</s>
<s>
The	O
OS/2	B-Application
emulation	O
is	O
handled	O
through	O
OS2SS.EXE	O
and	O
OS2.EXE	O
,	O
and	O
DOSCALLS.DLL	O
.	O
</s>
<s>
OS2.EXE	O
is	O
a	O
version	O
of	O
the	O
OS/2	B-Application
shell	O
(	O
CMD.EXE	B-Device
)	O
,	O
which	O
passes	O
commands	O
down	O
to	O
the	O
OS2SS.EXE	O
,	O
and	O
input-output	O
to	O
the	O
Windows	B-Device
NT	I-Device
shell	O
.	O
</s>
<s>
Windows	B-Application
2000	I-Application
was	O
the	O
last	O
version	O
of	O
NT	O
to	O
support	O
OS/2	B-Application
.	O
</s>
<s>
The	O
emulation	O
is	O
OS/2	B-Application
1.30	O
.	O
</s>
<s>
POSIX	O
is	O
emulated	O
through	O
the	O
POSIX	O
shell	O
,	O
but	O
no	O
emulated	O
shell	O
;	O
the	O
commands	O
are	O
handled	O
directly	O
in	O
CMD.EXE	B-Device
.	O
</s>
<s>
The	O
Command	B-Device
Prompt	I-Device
is	O
often	O
called	O
the	O
MS-DOS	B-Operating_System
Prompt	I-Operating_System
.	O
</s>
<s>
In	O
part	O
,	O
this	O
was	O
the	O
official	O
name	O
for	O
it	O
in	O
Windows	O
9x	O
and	O
early	O
versions	O
of	O
Windows	B-Device
NT	I-Device
(	O
NT	O
3.5	O
and	O
earlier	O
)	O
,	O
and	O
in	O
part	O
because	O
the	O
SoftPC	B-Device
emulation	O
of	O
DOS	B-Device
redirects	O
output	O
into	O
it	O
.	O
</s>
<s>
Actually	O
only	O
COMMAND.COM	B-Operating_System
and	O
other	O
16-bit	B-Device
commands	O
run	O
in	O
an	O
NTVDM	O
with	O
AUTOEXEC.NT	O
and	O
CONFIG.NT	B-Device
initialization	O
determined	O
by	O
_DEFAULT.PIF	O
,	O
optionally	O
permitting	O
the	O
use	O
of	O
Win32	B-Application
console	I-Application
applications	B-Application
and	O
internal	O
commands	O
with	O
an	O
NTCMDPROMPT	O
directive	O
.	O
</s>
<s>
Win32	B-Application
console	I-Application
applications	B-Application
use	O
CMD.EXE	B-Device
as	O
their	O
command	B-Device
prompt	I-Device
shell	O
.	O
</s>
<s>
This	O
confusion	O
does	O
not	O
exist	O
under	O
OS/2	B-Application
because	O
there	O
are	O
separate	O
DOS	B-Device
and	O
OS/2	B-Application
prompts	O
,	O
and	O
running	O
a	O
DOS	B-Device
program	O
under	O
OS/2	B-Application
will	O
launch	O
a	O
separate	O
DOS	B-Device
window	O
to	O
run	O
the	O
application	O
.	O
</s>
<s>
All	O
versions	O
of	O
Windows	O
for	O
Itanium	B-General_Concept
(	O
no	O
longer	O
sold	O
by	O
Microsoft	O
)	O
and	O
x86-64	B-Device
architectures	O
no	O
longer	O
include	O
the	O
NTVDM	O
and	O
can	O
therefore	O
no	O
longer	O
natively	O
run	O
DOS	B-Device
or	O
16-bit	B-Device
Windows	B-Application
applications	I-Application
.	O
</s>
<s>
There	O
are	O
alternatives	O
such	O
as	O
virtual	B-Architecture
machine	I-Architecture
emulators	O
such	O
as	O
Microsoft	O
's	O
own	O
Virtual	B-Application
PC	I-Application
,	O
as	O
well	O
as	O
VMware	O
,	O
DOSBox	B-Application
etc.	O
,	O
unofficial	O
compatibility	O
layers	O
such	O
as	O
NTVDMx64	O
,	O
OTVDM	O
(	O
WineVDM	O
)	O
,	O
Win3mu	O
and	O
others	O
.	O
</s>
<s>
The	O
introduction	O
of	O
Windows	B-Application
3.0	I-Application
in	O
1990	O
,	O
with	O
an	O
easy-to-use	O
graphical	B-Application
user	I-Application
interface	I-Application
,	O
marked	O
the	O
beginning	O
of	O
the	O
end	O
for	O
the	O
command-line	B-Application
driven	O
MS-DOS	B-Application
.	O
</s>
<s>
With	O
the	O
release	O
of	O
Windows	B-Application
95	I-Application
(	O
and	O
continuing	O
in	O
the	O
Windows	O
9x	O
product	O
line	O
through	O
to	O
Windows	B-Device
Me	I-Device
)	O
,	O
an	O
integrated	O
version	O
of	O
MS-DOS	B-Application
was	O
used	O
for	O
bootstrapping	O
,	O
troubleshooting	O
,	O
and	O
backwards-compatibility	O
with	O
old	O
DOS	B-Device
software	O
,	O
particularly	O
games	O
,	O
and	O
no	O
longer	O
released	O
as	O
a	O
standalone	O
product	O
.	O
</s>
<s>
In	O
Windows	B-Application
95	I-Application
,	O
the	O
DOS	B-Device
,	O
called	O
MS-DOS	B-Application
7	O
,	O
can	O
be	O
booted	O
separately	O
,	O
without	O
the	O
Windows	O
GUI	B-Application
;	O
this	O
capability	O
was	O
retained	O
through	O
Windows	B-Device
98	I-Device
Second	O
Edition	O
.	O
</s>
<s>
Windows	B-Device
Me	I-Device
removed	O
the	O
capability	O
to	O
boot	O
its	O
underlying	O
MS-DOS	B-Application
8.0	O
alone	O
from	O
a	O
hard	O
disk	O
,	O
but	O
retained	O
the	O
ability	O
to	O
make	O
a	O
DOS	B-Device
boot	O
floppy	B-Device
disk	I-Device
(	O
called	O
an	O
"	O
Emergency	O
Boot	O
Disk	O
"	O
)	O
and	O
can	O
be	O
hacked	O
to	O
restore	O
full	O
access	O
to	O
the	O
underlying	O
DOS	B-Device
.	O
</s>
<s>
On	O
December	O
31	O
,	O
2001	O
,	O
Microsoft	O
declared	O
all	O
versions	O
of	O
MS-DOS	B-Application
6.22	O
and	O
older	O
obsolete	O
and	O
stopped	O
providing	O
support	O
and	O
updates	O
for	O
the	O
system	O
.	O
</s>
<s>
As	O
MS-DOS	B-Application
7.0	O
was	O
a	O
part	O
of	O
Windows	B-Application
95	I-Application
,	O
support	O
for	O
it	O
also	O
ended	O
when	O
Windows	B-Application
95	I-Application
extended	O
support	O
ended	O
on	O
December	O
31	O
,	O
2001	O
.	O
</s>
<s>
As	O
MS-DOS	B-Application
7.10	O
and	O
MS-DOS	B-Application
8.0	O
were	O
part	O
of	O
Windows	B-Device
98	I-Device
and	O
Windows	B-Device
ME	I-Device
respectively	O
,	O
support	O
ended	O
when	O
Windows	B-Device
98	I-Device
and	O
ME	B-Device
extended	O
support	O
ended	O
on	O
July	O
11	O
,	O
2006	O
,	O
thus	O
ending	O
support	O
and	O
updates	O
of	O
MS-DOS	B-Application
from	O
Microsoft	O
.	O
</s>
<s>
In	O
contrast	O
to	O
the	O
Windows	O
9x	O
series	O
,	O
the	O
Windows	O
NT-derived	O
32-bit	O
operating	B-General_Concept
systems	I-General_Concept
(	O
Windows	B-Device
NT	I-Device
,	O
2000	B-Application
,	O
XP	B-Application
and	O
newer	O
)	O
,	O
developed	O
alongside	O
the	O
9x	O
series	O
,	O
do	O
not	O
contain	O
MS-DOS	B-Application
compatibility	O
as	O
a	O
core	O
component	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
nor	O
do	O
they	O
rely	O
on	O
it	O
for	O
bootstrapping	O
,	O
as	O
NT	O
was	O
not	O
with	O
the	O
level	O
of	O
support	O
for	O
legacy	O
MS-DOS	B-Application
and	O
Win16	O
apps	O
that	O
Windows	O
9x	O
was	O
,	O
but	O
does	O
provide	O
limited	O
DOS	B-Device
emulation	O
called	O
NTVDM	O
(	O
NT	O
Virtual	O
DOS	B-Device
Machine	O
)	O
to	O
run	O
DOS	B-Device
applications	B-Application
and	O
provide	O
DOS-like	O
command	B-Device
prompt	I-Device
windows	O
.	O
</s>
<s>
64-bit	B-Device
versions	O
of	O
Windows	B-Device
NT	I-Device
prior	O
to	O
Windows	B-Application
11	I-Application
do	O
not	O
provide	O
DOS	B-Device
emulation	O
and	O
cannot	O
run	O
DOS	B-Device
applications	B-Application
natively	O
.	O
</s>
<s>
Windows	B-Application
XP	I-Application
contains	O
a	O
copy	O
of	O
the	O
Windows	B-Device
Me	I-Device
boot	O
disk	O
,	O
stripped	O
down	O
to	O
bootstrap	O
only	O
.	O
</s>
<s>
This	O
is	O
accessible	O
only	O
by	O
formatting	O
a	O
floppy	B-Device
as	O
an	O
"	O
MS-DOS	B-Application
startup	O
disk	O
"	O
.	O
</s>
<s>
Files	O
like	O
the	O
driver	O
for	O
the	O
CD-ROM	O
support	O
were	O
deleted	O
from	O
the	O
Windows	B-Device
Me	I-Device
bootdisk	O
and	O
the	O
startup	O
files	O
(	O
AUTOEXEC.BAT	O
and	O
CONFIG.SYS	B-Device
)	O
no	O
longer	O
had	O
content	O
.	O
</s>
<s>
This	O
modified	O
disk	O
was	O
the	O
base	O
for	O
creating	O
the	O
MS-DOS	B-Application
image	O
for	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
When	O
booting	O
up	O
an	O
MS-DOS	B-Application
startup	O
disk	O
made	O
with	O
Windows	B-Application
XP	I-Application
's	O
format	O
tool	O
,	O
the	O
version	O
number	O
and	O
the	O
VER	B-Device
internal	O
command	O
reports	O
as	O
"	O
Windows	B-Device
Millennium	I-Device
"	O
and	O
"	O
5.1	O
"	O
,	O
respectively	O
,	O
and	O
not	O
as	O
"	O
MS-DOS	B-Application
8.0	B-Device
"	I-Device
(	O
which	O
was	O
used	O
as	O
the	O
base	O
for	O
Windows	B-Device
Me	I-Device
but	O
never	O
released	O
as	O
a	O
stand-alone	O
product	O
)	O
,	O
though	O
the	O
API	B-Application
still	O
says	O
Version	O
8.0	O
.	O
</s>
<s>
When	O
creating	O
a	O
DOS	B-Device
startup	O
disk	O
on	O
Windows	B-Application
Vista	I-Application
,	O
the	O
files	O
on	O
the	O
startup	O
disk	O
are	O
dated	O
April	O
18	O
,	O
2005	O
but	O
are	O
otherwise	O
unchanged	O
,	O
including	O
the	O
string	O
"	O
MS-DOS	B-Application
Version	O
8	O
Copyright	O
1981	O
–	O
1999	O
Microsoft	O
Corp	O
"	O
inside	O
COMMAND.COM	B-Operating_System
.	O
</s>
<s>
Windows	O
7	O
,	O
8	O
,	O
and	O
8.1	O
can	O
also	O
create	O
a	O
MS-DOS	B-Application
startup	O
disk	O
.	O
</s>
<s>
Starting	O
with	O
Windows	B-Operating_System
10	I-Operating_System
,	O
the	O
ability	O
to	O
create	O
a	O
DOS	B-Device
startup	O
disk	O
has	O
been	O
removed	O
and	O
so	O
either	O
a	O
virtual	B-Architecture
machine	I-Architecture
running	O
MS-DOS	B-Application
or	O
an	O
older	O
version	O
(	O
in	O
a	O
virtual	B-Architecture
machine	I-Architecture
or	O
dual	O
boot	O
)	O
must	O
be	O
used	O
to	O
format	O
a	O
floppy	B-Device
disk	I-Device
,	O
or	O
an	O
image	O
must	O
be	O
obtained	O
from	O
an	O
external	O
source	O
.	O
</s>
<s>
Other	O
solutions	O
include	O
using	O
DOS	B-Device
compatible	O
alternatives	O
,	O
such	O
as	O
FreeDOS	B-Application
or	O
even	O
copying	O
the	O
required	O
files	O
and	O
boot	O
sector	O
themselves	O
.	O
</s>
<s>
The	O
last	O
traces	O
of	O
MS-DOS	B-Application
would	O
be	O
removed	O
entirely	O
in	O
Windows	O
with	O
Windows	B-Application
11	I-Application
,	O
when	O
the	O
NTVDM	O
component	O
was	O
discontinued	O
from	O
the	O
operating	B-General_Concept
system	I-General_Concept
due	O
to	O
it	O
being	O
no	O
longer	O
offered	O
in	O
32-bit	O
versions	O
(	O
being	O
solely	O
offered	O
in	O
64-bit	B-Device
versions	O
only	O
)	O
,	O
thereby	O
ending	O
any	O
association	O
of	O
MS-DOS	B-Application
within	O
Microsoft	B-Application
Windows	I-Application
after	O
36	O
years	O
.	O
</s>
<s>
MS-DOS	B-Application
6.22	O
was	O
the	O
last	O
standalone	O
version	O
produced	O
by	O
Microsoft	O
for	O
Intel	B-Device
8088	I-Device
,	O
Intel	B-General_Concept
8086	I-General_Concept
,	O
and	O
Intel	B-General_Concept
80286	I-General_Concept
processors	O
,	O
which	O
remain	O
available	O
for	O
download	O
via	O
their	O
MSDN	O
,	O
volume	O
license	O
,	O
and	O
OEM	O
license	O
partner	O
websites	O
,	O
for	O
customers	O
with	O
valid	O
login	O
credentials	O
.	O
</s>
<s>
MS-DOS	B-Application
is	O
still	O
used	O
in	O
embedded	O
x86	B-Operating_System
systems	O
due	O
to	O
its	O
simple	O
architecture	O
and	O
minimal	O
memory	O
and	O
processor	O
requirements	O
,	O
though	O
some	O
current	O
products	O
have	O
switched	O
to	O
the	O
still-maintained	O
open-source	B-Application
alternative	O
FreeDOS	B-Application
.	O
</s>
<s>
In	O
2018	O
,	O
Microsoft	O
released	O
the	O
on	O
GitHub	B-Application
.	O
</s>
<s>
The	O
purpose	O
of	O
this	O
,	O
according	O
to	O
Microsoft	O
,	O
is	O
mainly	O
for	O
education	O
and	O
experimentation	O
with	O
historic	O
operating	B-General_Concept
systems	I-General_Concept
and	O
for	O
new	O
programmers	O
to	O
gain	O
an	O
understanding	O
of	O
how	O
low-level	O
software	O
works	O
,	O
both	O
historic	O
and	O
current	O
.	O
</s>
<s>
Users	O
,	O
however	O
,	O
are	O
allowed	O
and	O
fully	O
encouraged	O
to	O
fork	B-Application
the	O
repository	O
containing	O
the	O
MS-DOS	B-Application
source	O
code	O
and	O
make	O
their	O
own	O
modifications	O
,	O
and	O
do	O
whatever	O
they	O
like	O
with	O
it	O
.	O
</s>
<s>
From	O
1983	O
onwards	O
,	O
various	O
companies	O
worked	O
on	O
graphical	B-Application
user	I-Application
interfaces	I-Application
(	O
GUIs	B-Application
)	O
capable	O
of	O
running	O
on	O
PC	O
hardware	O
.	O
</s>
<s>
Later	O
,	O
in	O
1985	O
,	O
Microsoft	B-Application
Windows	I-Application
1.0	I-Application
was	O
released	O
as	O
Microsoft	O
's	O
first	O
attempt	O
at	O
providing	O
a	O
consistent	O
user	O
interface	O
(	O
for	O
applications	B-Application
)	O
.	O
</s>
<s>
The	O
early	O
versions	O
of	O
Windows	O
ran	O
on	O
top	O
of	O
MS-DOS	B-Application
.	O
</s>
<s>
At	O
first	O
Windows	O
met	O
with	O
little	O
success	O
,	O
but	O
this	O
was	O
also	O
true	O
for	O
most	O
other	O
companies	O
 '	O
efforts	O
as	O
well	O
,	O
for	O
example	O
GEM	B-Application
.	O
</s>
<s>
Windows	O
9x	O
used	O
MS-DOS	B-Application
to	O
boot	O
the	O
Windows	O
kernel	O
in	O
protected	O
mode	O
.	O
</s>
<s>
Basic	O
features	O
related	O
to	O
the	O
file	O
system	O
,	O
such	O
as	O
long	O
file	O
names	O
,	O
were	O
only	O
available	O
to	O
DOS	B-Device
applications	B-Application
when	O
running	O
through	O
Windows	O
.	O
</s>
<s>
Windows	B-Device
NT	I-Device
runs	O
independently	O
of	O
DOS	B-Device
but	O
includes	O
NTVDM	O
,	O
a	O
component	O
for	O
simulating	O
a	O
DOS	B-Device
environment	O
for	O
legacy	O
applications	B-Application
.	O
</s>
<s>
This	O
component	O
would	O
eventually	O
be	O
retired	O
starting	O
with	O
Windows	B-Application
11	I-Application
,	O
as	O
the	O
operating	B-General_Concept
system	I-General_Concept
is	O
only	O
being	O
offered	O
in	O
64-bit	B-Device
architectures	I-Device
such	O
as	O
x86-64	B-Device
.	O
</s>
<s>
MS-DOS	B-Application
compatible	O
systems	O
include	O
:	O
</s>
<s>
Microsoft	O
made	O
IBM	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
for	O
IBM	O
.	O
</s>
<s>
It	O
and	O
MS-DOS	B-Application
were	O
identical	O
products	O
that	O
eventually	O
diverged	O
starting	O
with	O
MS-DOS	B-Application
version	O
6.0	O
.	O
</s>
<s>
For	O
example	O
,	O
MS-DOS	B-Application
4	I-Application
,	O
released	O
in	O
July	O
1988	O
,	O
was	O
followed	O
by	O
DR	B-Application
DOS	I-Application
5.0	O
in	O
May	O
1990	O
.	O
</s>
<s>
MS-DOS	B-Application
5.0	O
came	O
in	O
April	O
1991	O
,	O
and	O
DR	B-Application
DOS	I-Application
6.0	O
was	O
released	O
the	O
following	O
June	O
.	O
</s>
<s>
These	O
products	O
are	O
collectively	O
referred	O
to	O
as	O
"	O
DOS	B-Device
"	O
,	O
even	O
though	O
"	O
Disk	B-Operating_System
Operating	I-Operating_System
System	I-Operating_System
"	O
is	O
a	O
generic	O
term	O
used	O
on	O
other	O
systems	O
unrelated	O
to	O
the	O
x86	B-Operating_System
and	O
IBM	B-Device
PC	I-Device
.	O
</s>
<s>
"	O
MS-DOS	B-Application
"	O
can	O
also	O
be	O
a	O
generic	O
reference	O
to	O
DOS	B-Device
on	O
IBM	B-Device
PC	I-Device
compatible	O
computers	O
.	O
</s>
<s>
Microsoft	O
's	O
control	O
of	O
the	O
Windows	O
platform	O
,	O
and	O
their	O
programming	O
practices	O
which	O
intentionally	O
made	O
Windows	O
appear	O
as	O
if	O
it	O
ran	O
poorly	O
on	O
competing	O
versions	O
of	O
DOS	B-Device
,	O
crippled	O
the	O
ability	O
of	O
other	O
DOS	B-Device
makers	O
to	O
continue	O
to	O
compete	O
with	O
MS-DOS	B-Application
.	O
</s>
