<s>
The	O
Z80	B-General_Concept
Operating	B-General_Concept
System	I-General_Concept
with	O
Relocatable	O
Modules	O
and	O
I/O	O
Management	O
(	O
Z80-RIO	B-Device
)	O
is	O
a	O
general-purpose	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
developed	O
by	O
Zilog	O
in	O
the	O
late	O
1970s	O
for	O
various	O
computer	O
systems	O
including	O
the	O
Z80	B-General_Concept
Micro	O
Computer	O
System	O
(	O
MCZ-1	O
)	O
series	O
and	O
the	O
Z80	B-General_Concept
Development	O
System	O
(	O
ZDS	O
)	O
.	O
</s>
<s>
The	O
modest	O
environment	O
provides	O
a	O
program	O
debugger	B-Application
with	O
file	O
manipulation	O
capability	O
,	O
a	O
floppy	B-Device
disk	I-Device
driver	O
(	O
supporting	O
up	O
to	O
eight	O
disk	O
drives	O
)	O
,	O
and	O
a	O
basic	O
console	O
driver	O
with	O
provision	O
for	O
paper	O
tape	O
operation	O
.	O
</s>
<s>
The	O
enhanced	O
environment	O
provides	O
access	O
to	O
the	O
RIO	B-Device
Executive	I-Device
and	O
to	O
system	O
support	O
utilities	O
such	O
as	O
the	O
Zilog	B-Device
Floppy	I-Device
Disk	I-Device
File	I-Device
System	I-Device
(	O
ZDOS	B-Device
)	O
,	O
and	O
the	O
Zilog	B-Device
Hard	I-Device
Disk	I-Device
File	I-Device
System	I-Device
(	O
DFS	B-Device
)	O
.	O
</s>
<s>
It	O
also	O
provides	O
access	O
to	O
a	O
number	O
of	O
disk-resident	O
software	O
such	O
a	O
text	B-Application
editor	I-Application
,	O
macro	B-Language
assembler	I-Language
,	O
and	O
linker	B-Application
.	O
</s>
<s>
The	O
following	O
list	O
of	O
commands	B-Application
are	O
supported	O
by	O
Z80-RIO	B-Device
.	O
</s>
<s>
UDOS	O
,	O
a	O
Z80-RIO	B-Device
compatible	O
clone	O
by	O
VEB	O
Robotron	O
,	O
was	O
available	O
for	O
a	O
number	O
of	O
computers	O
by	O
the	O
same	O
company	O
,	O
such	O
as	O
the	O
A	O
5120	O
or	O
the	O
PC	O
1715	O
,	O
which	O
were	O
based	O
on	O
the	O
U880	B-Device
processor	O
(	O
the	O
latter	O
being	O
a	O
clone	O
of	O
Zilog	O
's	O
Z80	B-General_Concept
)	O
.	O
</s>
<s>
UDOS	O
was	O
also	O
one	O
of	O
the	O
operating	B-General_Concept
systems	I-General_Concept
available	O
for	O
the	O
P8000	O
,	O
a	O
microcomputer	O
system	O
developed	O
in	O
1987	O
by	O
the	O
VEB	O
Elektro-Apparate-Werke	O
Berlin-Treptow	O
„Friedrich	O
Ebert	O
“	O
(	O
EAW	O
)	O
in	O
the	O
German	O
Democratic	O
Republic	O
(	O
DDR	O
,	O
East	O
Germany	O
)	O
.	O
</s>
