<s>
Edos	B-Application
is	O
a	O
discontinued	O
operating	B-General_Concept
system	I-General_Concept
based	O
upon	O
IBM	O
's	O
original	O
mainframe	B-Application
DOS	I-Application
(	O
not	O
to	O
be	O
confused	O
with	O
the	O
unrelated	O
and	O
better	O
known	O
MS-DOS	B-Application
for	O
the	O
IBM	O
PC	O
)	O
.	O
</s>
<s>
The	O
name	O
stood	O
for	O
extended	O
(	O
or	O
enhanced	O
)	O
disk	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
It	O
was	O
later	O
purchased	O
by	O
the	O
West	O
German	O
computer	O
company	O
Nixdorf	O
,	O
who	O
renamed	O
it	O
to	O
NIDOS	O
(	O
Nixdorf	O
Disk	O
Operating	B-General_Concept
System	I-General_Concept
)	O
.	O
</s>
<s>
In	O
1970	O
,	O
IBM	O
announced	O
the	O
IBM/370	B-Device
product	O
line	O
along	O
with	O
new	O
peripherals	O
,	O
software	O
products	O
,	O
and	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
DOS/VS	B-Application
that	O
supplanted	O
DOS	B-Device
.	O
</s>
<s>
Although	O
IBM	O
was	O
rightly	O
focused	O
on	O
their	O
new	O
products	O
,	O
the	O
computing	O
world	O
was	O
dominated	O
by	O
the	O
IBM/360	B-Application
line	O
,	O
which	O
left	O
a	O
lot	O
of	O
users	O
nervous	O
about	O
their	O
investment	O
.	O
</s>
<s>
Although	O
there	O
were	O
a	O
couple	O
of	O
projects	O
emulating	O
the	O
IBM/370	B-Device
on	O
the	O
IBM/360	B-Application
(	O
e.g.	O
,	O
CFS	O
,	O
Inc	O
.	O
)	O
,	O
other	O
companies	O
took	O
a	O
different	O
approach	O
,	O
extending	O
the	O
then-current	O
(	O
and	O
limited	O
)	O
DOS	B-Device
.	O
</s>
<s>
The	B-Application
Computer	I-Application
Software	I-Application
Company	I-Application
(	O
TCSC	O
)	O
took	O
the	O
latter	O
approach	O
.	O
</s>
<s>
Starting	O
in	O
1972	O
,	O
they	O
developed	O
Edos	B-Application
,	O
Extended	O
Disk	O
Operating	B-General_Concept
System	I-General_Concept
.	O
</s>
<s>
The	O
first	O
version	O
of	O
Edos	B-Application
was	O
released	O
in	O
1972	O
,	O
in	O
response	O
to	O
the	O
announcement	O
by	O
IBM	O
that	O
DOS	B-Device
Release	O
26	O
was	O
the	O
last	O
DOS	B-Device
release	O
to	O
be	O
supported	O
on	O
the	O
System	B-Application
360	I-Application
,	O
and	O
future	O
DOS	B-Device
Releases	O
would	O
support	O
System	B-Device
370	I-Device
machines	O
only	O
.	O
</s>
<s>
They	O
also	O
made	O
available	O
other	O
third	O
party	O
enhancements	O
such	O
as	O
a	O
spooler	B-Device
and	O
DOCS	B-Application
,	O
from	O
CFS	O
,	O
Inc	O
.	O
</s>
<s>
TCSC	O
enhanced	O
EDOS	B-Application
to	O
become	O
EDOS/VS	B-Application
,	O
which	O
was	O
announced	O
in	O
1977	O
and	O
delivered	O
it	O
to	O
beta	O
test	O
sites	O
in	O
1978	O
.	O
</s>
<s>
In	O
May	O
1977	O
,	O
TCSC	O
announced	O
it	O
would	O
release	O
Edos/VS	B-Application
in	O
response	O
to	O
IBM	O
's	O
release	O
of	O
DOS/VS	B-Application
Release	O
34	O
and	O
Advanced	O
Functions-DOS/VS	O
.	O
</s>
<s>
Edos/VS	B-Application
was	O
based	O
on	O
IBM	O
's	O
DOS/VS	B-Application
Release	O
34	O
,	O
and	O
provided	O
equivalent	O
functionality	O
to	O
IBM	O
's	O
Advanced	O
Functions-DOS/VS	O
product	O
.	O
</s>
<s>
Unlike	O
IBM	O
's	O
offerings	O
,	O
Edos/VS	B-Application
would	O
run	O
on	O
System	B-Application
360	I-Application
machines	O
and	O
System	B-Device
370	I-Device
machines	O
lacking	O
virtual	O
storage	O
hardware	O
(	O
non-VS	O
machines	O
)	O
,	O
whereas	O
IBM	O
's	O
offerings	O
only	O
supported	O
the	O
latest	O
System	B-Device
370	I-Device
models	O
with	O
VS	O
hardware	O
included	O
.	O
</s>
<s>
TCSC	O
identified	O
the	O
parts	O
of	O
IBM	O
's	O
DOS/VS	B-Application
Release	O
34	O
operating	B-General_Concept
system	I-General_Concept
which	O
relied	O
upon	O
System/370	B-Device
-only	O
machine	O
instructions	O
and	O
rewrote	O
them	O
to	O
use	O
instructions	O
supported	O
by	O
the	O
System/360	B-Application
.	O
</s>
<s>
TCSC	O
was	O
legally	O
able	O
to	O
reuse	O
IBM	O
's	O
DOS/VS	B-Application
Release	O
34	O
code	O
,	O
since	O
IBM	O
had	O
(	O
intentionally	O
)	O
published	O
the	O
code	O
without	O
a	O
copyright	O
notice	O
,	O
which	O
made	O
it	O
public	O
domain	O
under	O
US	O
copyright	O
law	O
at	O
the	O
time	O
.	O
</s>
<s>
In	O
1981	O
,	O
NCSC	O
announced	O
plans	O
to	O
release	O
an	O
Edos/VSE	B-Application
2.0	O
,	O
based	O
on	O
IBM	O
DOS/VSE	O
Release	O
35	O
,	O
suitable	O
for	O
IBM	B-Device
4300	I-Device
machines	O
.	O
</s>
<s>
Econ	O
was	O
available	O
for	O
IBM	O
's	O
DOS	B-Device
and	O
DOS/VS	B-Application
and	O
TCSC	O
's	O
Edos	B-Application
and	O
Edos/VS	B-Application
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
By	O
1982	O
,	O
Nixdorf	O
had	O
renamed	O
Edos	B-Application
to	O
NIDOS/VSE	O
,	O
and	O
was	O
selling	O
to	O
run	O
on	O
their	O
new	O
Nixdorf	O
8890	O
series	O
of	O
IBM-compatible	O
mainframes	O
.	O
</s>
<s>
TCSC	O
licensed	O
DATACOM/DB	B-Application
from	O
Applied	B-Operating_System
Data	I-Operating_System
Research	I-Operating_System
(	O
ADR	O
)	O
to	O
run	O
under	O
its	O
EDos	B-Application
and	O
EDos/VS	B-Application
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
In	O
1973	O
,	O
TCSC	O
released	O
a	O
remote	B-Protocol
job	I-Protocol
entry	I-Protocol
(	O
RJE	B-Protocol
)	O
option	O
for	O
Edos	B-Application
.	O
</s>
<s>
In	O
1975	O
,	O
TCSC	O
released	O
a	O
tape	B-General_Concept
management	I-General_Concept
system	I-General_Concept
for	O
Edos	B-Application
known	O
as	O
TMS	O
.	O
</s>
<s>
In	O
1983	O
,	O
NCSC	O
announced	O
a	O
Unix	O
compatibility	O
subsystem	O
for	O
IBM	O
mainframes	O
running	O
IBM	O
's	O
DOS/VS	B-Application
( E	O
)	O
and	O
Nixdorf	O
's	O
Edos/VS	B-Application
and	O
Edos/VSE	B-Application
operating	B-General_Concept
systems	I-General_Concept
,	O
known	O
as	O
Programmer	O
Work	O
Station/VSE	O
-Advanced	O
Functions	O
,	O
or	O
PWS/VSE	O
-AF	O
for	O
short	O
.	O
</s>
<s>
PWS/VSE	O
-AF	O
was	O
based	O
on	O
the	O
Coherent	B-Operating_System
Unix	O
clone	O
developed	O
by	O
Mark	O
Williams	O
Company	O
.	O
</s>
<s>
However	O
,	O
while	O
Comparex	O
was	O
willing	O
to	O
take	O
over	O
the	O
hardware	O
business	O
,	O
it	O
did	O
not	O
want	O
the	O
responsibility	O
of	O
maintaining	O
the	O
Edos	B-Application
operating	B-General_Concept
system	I-General_Concept
,	O
preferring	O
instead	O
that	O
its	O
customers	O
purchase	O
DOS/VSE	O
or	O
MVS	O
from	O
IBM	O
.	O
</s>
<s>
Nixdorf	O
decided	O
to	O
cancel	O
all	O
work	O
on	O
the	O
next	O
release	O
of	O
Edos	B-Application
,	O
since	O
they	O
did	O
not	O
want	O
to	O
commit	O
to	O
maintain	O
any	O
new	O
version	O
in	O
the	O
years	O
to	O
come	O
.	O
</s>
