<s>
MSX-DOS	B-Operating_System
is	O
a	O
discontinued	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
developed	O
by	O
Microsoft	O
for	O
the	O
8-bit	O
home	O
computer	O
standard	O
MSX	B-Operating_System
,	O
and	O
is	O
a	O
cross	O
between	O
MS-DOS	O
1.25	O
and	O
CP/M	B-Application
-802	O
.	O
</s>
<s>
MSX-DOS	B-Operating_System
and	O
the	O
extended	O
BASIC	O
with	O
3½-inch	O
floppy	B-Device
disk	I-Device
support	O
were	O
simultaneously	O
developed	O
by	O
Microsoft	O
and	O
Spectravideo	O
as	O
a	O
software	O
and	O
hardware	O
standard	O
for	O
the	O
MSX	B-Operating_System
home	O
computer	O
standard	O
,	O
to	O
add	O
disk	O
capabilities	O
to	O
BASIC	O
and	O
to	O
give	O
the	O
system	O
a	O
cheaper	O
software	O
medium	O
than	O
Memory	O
Cartridges	B-Protocol
,	O
and	O
a	O
more	B-Device
powerful	O
storage	O
system	O
than	O
cassette	B-Device
tape	I-Device
.	O
</s>
<s>
The	O
standard	B-Operating_System
BIOS	I-Operating_System
of	O
an	O
unexpanded	O
MSX	B-Operating_System
computer	O
did	O
not	O
have	O
any	O
floppy	B-Device
disk	I-Device
support	O
,	O
so	O
the	O
additional	O
floppy	B-Device
disk	I-Device
expansion	O
system	O
came	O
with	O
its	O
own	O
BIOS	B-Operating_System
extension	O
ROM	O
(	O
built-in	O
on	O
the	O
disk	O
controller	O
)	O
called	O
the	O
BDOS	O
.	O
</s>
<s>
Spectravideo	O
also	O
released	O
an	O
MSX-DOS	B-Operating_System
disk	O
in	O
conjunction	O
with	O
the	O
SVI-707	O
which	O
could	O
be	O
loaded	O
into	O
an	O
MSX	B-Operating_System
system	O
.	O
</s>
<s>
Once	O
MSX-DOS	B-Operating_System
has	O
been	O
loaded	O
,	O
the	O
system	O
searches	O
the	O
MSX-DOS	B-Operating_System
disk	O
for	O
the	O
COMMAND.COM	B-Operating_System
file	O
and	O
loads	O
it	O
into	O
memory	O
.	O
</s>
<s>
It	O
not	O
only	O
added	O
floppy	B-Device
disk	I-Device
support	O
commands	B-Application
to	O
MSX	B-Language
BASIC	I-Language
,	O
but	O
also	O
a	O
booting	B-Operating_System
system	O
,	O
with	O
which	O
it	O
was	O
possible	O
to	O
boot	B-Operating_System
a	O
real	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
In	O
that	O
case	O
,	O
the	O
BDOS	O
bypassed	O
the	O
BASIC	O
ROMs	O
,	O
so	O
that	O
the	O
whole	O
64KB	O
of	O
address	O
space	O
of	O
the	O
Z80	B-General_Concept
microprocessor	I-General_Concept
inside	O
the	O
MSX	B-Operating_System
computer	O
could	O
be	O
used	O
for	O
the	O
DOS	B-Device
or	O
for	O
other	O
boot-able	O
disks	O
,	O
for	O
example	O
disk	O
based	O
games	O
.	O
</s>
<s>
At	O
the	O
same	O
time	B-Device
,	O
the	O
original	O
BIOS	B-Operating_System
ROMs	O
could	O
still	O
be	O
accessed	O
through	O
a	O
"	O
memory	O
bank	B-General_Concept
switch	I-General_Concept
"	O
mechanism	O
,	O
so	O
that	O
DOS-based	O
software	O
could	O
still	O
use	O
BIOS	B-Operating_System
calls	O
to	O
control	O
the	O
hardware	O
and	O
other	O
software	O
mechanisms	O
the	O
main	O
ROMs	O
supplied	O
.	O
</s>
<s>
Also	O
,	O
due	O
to	O
the	O
BDOS	O
ROM	O
,	O
basic	O
file	B-Application
access	I-Application
capabilities	O
were	O
available	O
even	O
without	O
a	O
command	O
interpreter	O
by	O
using	O
extended	O
BASIC	O
commands	B-Application
.	O
</s>
<s>
At	O
initial	O
startup	O
,	O
COMMAND.COM	B-Operating_System
looks	O
for	O
an	O
optional	O
batch	O
file	O
named	O
AUTOEXEC.BAT	O
and	O
,	O
if	O
it	O
exists	O
,	O
executes	O
the	O
commands	B-Application
specified	O
in	O
there	O
.	O
</s>
<s>
If	O
MSX-DOS	B-Operating_System
is	O
not	O
invoked	O
and	O
Disk	B-Language
BASIC	I-Language
starts	O
,	O
a	O
BASIC	O
program	O
named	O
"	O
AUTOEXEC.BAS	B-Operating_System
"	O
will	O
be	O
carried	O
out	O
instead	O
,	O
if	O
present	O
.	O
</s>
<s>
One	O
major	O
difference	O
between	O
MSX-DOS	B-Operating_System
and	O
MS-DOS	O
2.x	O
was	O
that	O
MSX-DOS	B-Operating_System
did	O
not	O
use	O
the	O
"	O
boot	B-Operating_System
sector	O
"	O
on	O
the	O
floppy	B-Device
to	O
boot	B-Operating_System
,	O
but	O
instead	O
booted	O
using	O
the	O
BDOS	O
ROM	O
routines	O
,	O
and	O
,	O
in	O
a	O
fashion	O
much	O
like	O
MS-DOS	O
1.25	O
,	O
it	O
used	O
the	O
FAT	B-Application
ID	O
value	O
from	O
the	O
first	O
byte	O
of	O
the	O
FAT	B-Application
to	O
select	O
file	B-Application
system	I-Application
parameter	O
profiles	O
for	O
its	O
FAT12	B-Application
file	B-Application
system	I-Application
instead	O
of	O
from	O
the	O
BIOS	B-Operating_System
Parameter	O
Block	O
(	O
BPB	O
)	O
in	O
the	O
boot	B-Operating_System
sector	O
.	O
</s>
<s>
Also	O
,	O
because	O
there	O
could	O
be	O
more	B-Device
than	O
one	O
floppy	B-Device
disk	I-Device
controller	O
in	O
two	O
or	O
more	B-Device
cartridge	B-Protocol
slots	O
,	O
MSX-DOS	B-Operating_System
could	O
boot	B-Operating_System
from	O
several	O
different	O
floppy	B-Device
disk	I-Device
drives	I-Device
.	O
</s>
<s>
This	O
meant	O
that	O
it	O
was	O
possible	O
to	O
have	O
both	O
,	O
a	O
5¼	O
"	O
floppy	B-Device
disk	I-Device
drive	I-Device
and	O
a	O
3½	O
"	O
disk	O
drive	O
,	O
and	O
the	O
user	O
could	O
boot	B-Operating_System
from	O
either	O
one	O
of	O
them	O
depending	O
on	O
which	O
drive	O
had	O
a	O
bootable	B-Operating_System
floppy	B-Device
in	O
it	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
list	O
of	O
internal	O
commands	B-Application
supported	O
by	O
MSX-DOS	B-Operating_System
.	O
</s>
<s>
On	O
10	O
August	O
1983	O
,	O
Paul	O
Allen	O
called	O
Tim	O
Paterson	O
,	O
original	O
author	O
of	O
86-DOS	B-Operating_System
and	O
MS-DOS	O
1.x	O
,	O
asking	O
him	O
to	O
do	O
a	O
"	O
Z80	B-General_Concept
version	O
of	O
MS-DOS	O
"	O
for	O
the	O
MSX	B-Operating_System
standard	O
.	O
</s>
<s>
At	O
the	O
time	B-Device
,	O
Paterson	O
was	O
busy	O
trying	O
to	O
get	O
the	O
first	O
product	O
of	O
his	O
startup	O
Falcon	O
Systems	O
ready	O
to	O
go	O
,	O
so	O
he	O
suggested	O
a	O
few	O
other	O
developers	O
,	O
but	O
Allen	O
said	O
he	O
had	O
already	O
asked	O
.	O
</s>
<s>
Allen	O
and	O
Paterson	O
finally	O
agreed	O
,	O
and	O
on	O
17	O
August	O
,	O
they	O
signed	O
an	O
agreement	O
to	O
do	O
"	O
Z80	B-Operating_System
MS-DOS	I-Operating_System
1.25	O
"	O
for	O
US$	O
100,000	O
and	O
the	O
rights	O
for	O
Paterson	O
's	O
company	O
to	O
distribute	O
MS-DOS	O
2.0	O
,	O
2.5	O
,	O
and	O
3.0	O
with	O
a	O
hardware	O
product	O
without	O
royalty	O
.	O
</s>
<s>
He	O
had	O
already	O
written	O
a	O
Z80-to-8086	O
assembly	B-Language
language	I-Language
translation	O
program	O
(	O
TRANS.COM	O
)	O
.	O
</s>
<s>
Because	O
MS-DOS	O
1.x	O
was	O
modelled	O
after	O
CP/M	B-Application
'	O
s	O
API	B-Application
and	O
was	O
able	O
to	O
run	O
CP/M	B-Application
applications	O
that	O
had	O
been	O
source-level	O
translated	O
to	O
8086	O
,	O
that	O
would	O
mean	O
,	O
MSX-DOS	B-Operating_System
would	O
be	O
able	O
to	O
run	O
CP/M	B-Application
programs	O
directly	O
.	O
</s>
<s>
For	O
this	O
project	O
,	O
Paterson	O
also	O
wrote	O
a	O
Z80	B-General_Concept
emulator	O
that	O
ran	O
under	O
MS-DOS	O
,	O
which	O
would	O
allow	O
him	O
to	O
do	O
the	O
entire	O
development	O
project	O
under	O
MS-DOS	O
.	O
</s>
<s>
The	O
MSX-DOS	B-Operating_System
he	O
was	O
writing	O
had	O
an	O
I/O	O
System	O
layer	O
,	O
that	O
interfaced	O
directly	O
to	O
the	O
I/O	O
System	O
layer	O
of	O
the	O
MS-DOS	O
machine	O
,	O
that	O
was	O
running	O
the	O
emulation	O
.	O
</s>
<s>
This	O
gave	O
MSX-DOS	B-Operating_System
direct	O
access	O
and	O
control	O
of	O
the	O
disk	O
format	B-Application
.	O
</s>
<s>
By	O
2	O
October	O
1983	O
,	O
he	O
had	O
Microsoft	B-Language
BASIC	I-Language
and	O
Microsoft	B-Device
M80	I-Device
macro	B-Language
assembler	I-Language
running	O
under	O
MSX-DOS	B-Operating_System
.	O
</s>
<s>
He	O
finished	O
coding	O
COMMAND.COM	B-Operating_System
a	O
few	O
days	O
later	O
.	O
</s>
<s>
He	O
worked	O
out	O
some	O
bugs	O
and	O
demonstrated	O
MSX-DOS	B-Operating_System
to	O
Paul	O
Allen	O
on	O
11	O
October	O
.	O
</s>
<s>
The	O
name	O
was	O
encoded	O
with	O
FAT	B-Application
code	O
,	O
so	O
it	O
could	O
not	O
be	O
found	O
by	O
simply	O
searching	O
the	O
file	O
.	O
</s>
<s>
They	O
created	O
the	O
I/O	O
System	O
for	O
the	O
MSX	B-Operating_System
machine	O
.	O
</s>
<s>
ASCII	O
was	O
having	O
problems	O
getting	O
MSX-DOS	B-Operating_System
working	O
on	O
the	O
actual	O
MSX	B-Operating_System
machine	O
.	O
</s>
<s>
They	O
had	O
not	O
provided	O
an	O
actual	O
MSX	B-Operating_System
machine	O
to	O
Paterson	O
,	O
and	O
instead	O
flew	O
him	O
to	O
Tokyo	O
on	O
28	O
January	O
1984	O
to	O
help	B-Protocol
them	O
.	O
</s>
<s>
They	O
brought	O
an	O
MSX	B-Operating_System
machine	O
with	O
an	O
in-circuit	B-Application
emulator	I-Application
(	O
ICE	O
)	O
for	O
debugging	O
.	O
</s>
<s>
They	O
got	O
everything	O
working	O
and	O
on	O
23	O
April	O
1984	O
,	O
Microsoft	O
accepted	O
delivery	O
and	O
made	O
the	O
final	O
payment	O
for	O
MSX-DOS	B-Operating_System
to	O
Paterson	O
.	O
</s>
<s>
At	O
the	O
time	B-Device
MSX-DOS	B-Operating_System
was	O
written	O
,	O
there	O
was	O
only	O
one	O
popular	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
for	O
8-bit	O
Intel	B-General_Concept
8080	I-General_Concept
compatible	O
microprocessors	O
,	O
which	O
was	O
Digital	O
Research	O
's	O
CP/M	B-Application
-80	I-Application
system	O
.	O
</s>
<s>
It	O
was	O
also	O
often	O
used	O
with	O
Z80	B-General_Concept
systems	O
,	O
because	O
the	O
Z80	B-General_Concept
used	O
an	O
extended	O
8080	B-General_Concept
architecture	O
.	O
</s>
<s>
Microsoft	O
's	O
own	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
was	O
also	O
inspired	O
by	O
CP/M	B-Application
.	O
</s>
<s>
To	O
be	O
able	O
to	O
run	O
(	O
slightly	O
modified	O
)	O
CP/M	B-Application
software	O
Microsoft	O
decided	O
to	O
implement	O
functionality	O
similar	O
to	O
major	O
parts	O
of	O
the	O
CP/M	B-Application
BIOS	B-Operating_System
,	O
routines	O
that	O
CP/M	B-Application
systems	O
used	O
to	O
do	O
specific	O
disk	O
operating	O
tasks	O
,	O
such	O
as	O
opening	O
files	O
,	O
etc	O
.	O
</s>
<s>
Instead	O
of	O
basing	O
the	O
command	O
processor	O
on	O
CP/M	B-Application
'	O
s	O
CCP	O
,	O
which	O
was	O
known	O
for	O
some	O
user	O
unfriendliness	O
,	O
a	O
command	B-Application
line	I-Application
interpreter	O
(	O
COMMAND.COM	B-Operating_System
)	O
based	O
on	O
its	O
MS-DOS	O
counterpart	O
was	O
used	O
.	O
</s>
<s>
Microsoft	O
also	O
chose	O
its	O
own	O
FAT12	B-Application
file	B-Application
system	I-Application
over	O
CP/M	B-Application
'	O
s	O
filing	O
methods	O
.	O
</s>
<s>
This	O
ensured	O
that	O
MSX-DOS	B-Operating_System
floppies	B-Device
could	O
be	O
used	O
on	O
an	O
MS-DOS	O
machine	O
,	O
and	O
that	O
only	O
one	O
single	O
formatting	O
and	O
filing	O
system	O
would	O
be	O
used	O
.	O
</s>
<s>
This	O
was	O
an	O
important	O
decision	O
,	O
because	O
CP/M	B-Application
disks	O
were	O
often	O
not	O
interchangeable	O
between	O
machines	O
,	O
incompatible	O
disk	O
formatting	O
schemes	O
being	O
a	O
factor	O
in	O
this	O
.	O
</s>
<s>
Microsoft	O
also	O
added	O
a	O
standard	O
set	O
of	O
disk	O
commands	B-Application
to	O
MSX-DOS	B-Operating_System
that	O
were	O
compatible	O
with	O
MS-DOS	O
but	O
not	O
with	O
CP/M	B-Application
.	O
</s>
<s>
Finally	O
they	O
converted	O
their	O
pipelining	B-Operating_System
system	O
from	O
MS-DOS	O
to	O
MSX-DOS	B-Operating_System
.	O
</s>
<s>
The	O
resulting	O
DOS	B-Device
was	O
a	O
system	O
that	O
was	O
much	O
user-friendlier	O
than	O
CP/M	B-Application
,	O
but	O
was	O
(	O
in	O
principle	O
)	O
compatible	O
with	O
major	O
CP/M	B-Application
software	O
packages	O
such	O
as	O
WordStar	B-Application
,	O
Turbo	B-Application
Pascal	I-Application
and	O
the	O
"	O
M80	O
"	O
assembler	B-Language
and	O
"	O
L80	O
"	O
linker	O
.	O
</s>
<s>
Like	O
MS-DOS	O
1.25	O
,	O
the	O
first	O
version	O
of	O
MSX-DOS	B-Operating_System
did	O
not	O
have	O
subdirectories	B-Application
,	O
but	O
in	O
1988	O
it	O
evolved	O
to	O
version	O
2	O
,	O
offering	O
facilities	O
such	O
as	O
subdirectories	B-Application
,	O
memory	O
management	O
and	O
environment	O
strings	O
.	O
</s>
<s>
Later	O
versions	O
of	O
MSX	B-Operating_System
computers	O
(	O
MSX-2	O
)	O
added	O
an	O
internal	O
real-time	O
clock	O
,	O
which	O
MSX-DOS	B-Operating_System
could	O
use	O
for	O
time	B-Device
stamping	O
files	O
.	O
</s>
<s>
The	O
following	O
commands	B-Application
are	O
supported	O
by	O
MSX-DOS	B-Operating_System
version	O
2	O
.	O
</s>
<s>
In	O
addition	O
,	O
ASCII	O
provided	O
the	O
following	O
MSX-DOS2	O
Tools	O
.	O
</s>
