<s>
CD-Cops	B-Operating_System
is	O
the	O
first	O
CD-ROM	B-Device
protection	O
that	O
uses	O
the	O
geometry	O
of	O
the	O
CD-ROM	B-Device
media	O
rather	O
than	O
a	O
hidden	O
"	O
mark	O
"	O
.	O
</s>
<s>
It	O
was	O
invented	O
in	O
1996	O
by	O
Danish	O
Link	O
Data	O
Security	O
,	O
known	O
for	O
its	O
Cops	O
Copylock	O
key-diskette	O
security	O
used	O
in	O
the	O
1990s	O
by	O
Lotus	B-Application
1-2-3	I-Application
.	O
</s>
<s>
As	O
a	O
copy	O
(	O
CD-R	O
or	O
CD-ROM	B-Device
)	O
will	O
have	O
a	O
different	O
geometry	O
,	O
Data	B-Device
Position	I-Device
Measurement	I-Device
needs	O
to	O
be	O
used	O
for	O
copies	O
.	O
</s>
<s>
The	O
geometry	O
is	O
not	O
known	O
before	O
CDs	O
have	O
been	O
produced	O
,	O
therefore	O
a	O
CD-code	O
expressing	O
the	O
layout	O
of	O
the	O
CD-ROM	B-Device
must	O
be	O
entered	O
the	O
first	O
time	O
a	O
user	O
runs	O
the	O
protected	O
software	O
.	O
</s>
<s>
Using	O
a	O
special	O
production	O
process	O
in	O
some	O
cases	O
the	O
CD-code	O
is	O
embedded	O
on	O
the	O
CD-ROM	B-Device
.	O
</s>
<s>
CD-Cops	B-Operating_System
is	O
popular	O
for	O
encyclopaedias/dictionaries	O
and	O
business	O
applications	O
but	O
not	O
used	O
as	O
much	O
for	O
games	O
.	O
</s>
<s>
DVD-Cops	B-Operating_System
based	O
on	O
the	O
same	O
principles	O
in	O
1998	O
was	O
the	O
first	O
DVD-ROM	O
protection	O
made	O
.	O
</s>
