<s>
The	O
WDR	B-Application
paper	I-Application
computer	I-Application
or	O
Know-how	B-Application
Computer	I-Application
is	O
an	O
educational	O
model	O
of	O
a	O
computer	O
consisting	O
only	O
of	O
a	O
pen	O
,	O
a	O
sheet	O
of	O
paper	O
,	O
and	O
individual	O
matches	O
in	O
the	O
most	O
simple	O
case	O
.	O
</s>
<s>
The	O
paper	O
computer	O
was	O
created	O
in	O
the	O
early	O
1980s	O
when	O
computer	O
access	O
was	O
not	O
yet	O
widespread	O
in	O
Germany	O
,	O
to	O
allow	O
people	O
to	O
familiarize	O
themselves	O
with	O
basic	O
computer	O
operation	O
and	O
assembly-like	O
programming	O
languages	O
.	O
</s>
<s>
The	O
Know-how	B-Application
Computer	I-Application
was	O
developed	O
by	O
and	O
Ulrich	O
Rohde	O
and	O
was	O
first	O
presented	O
in	O
the	O
television	O
program	O
WDR	O
Computerclub	O
in	O
1983	O
.	O
</s>
<s>
The	O
original	O
printed	O
version	O
of	O
the	O
paper	O
computer	O
has	O
up	O
to	O
21	O
lines	O
of	O
code	O
on	O
the	O
left	O
and	O
eight	O
registers	O
on	O
the	O
right	O
,	O
which	O
are	O
represented	O
as	O
boxes	O
that	O
contain	O
as	O
many	O
matches	O
as	O
the	O
value	O
in	O
the	O
corresponding	O
register	B-General_Concept
.	O
</s>
<s>
The	O
instruction	O
set	O
of	O
five	O
commands	O
is	O
small	O
but	O
Turing	B-Algorithm
complete	I-Algorithm
and	O
therefore	O
enough	O
to	O
represent	O
all	O
mathematical	O
functions	O
:	O
</s>
<s>
inc	O
*	O
register*	O
:	O
Add	O
1	O
to	O
the	O
register	B-General_Concept
.	O
</s>
<s>
dec	O
*	O
register*	O
:	O
Subtract	O
1	O
from	O
the	O
register	B-General_Concept
.	O
</s>
<s>
isz	O
*	O
register*	O
:	O
Checks	O
if	O
the	O
register	B-General_Concept
is	O
zero	O
.	O
</s>
<s>
0	O
=	O
Check	O
if	O
the	O
content	O
of	O
the	O
data	O
register	B-General_Concept
XX	O
is	O
equal	O
to	O
0	O
.	O
</s>
<s>
An	O
emulator	O
for	O
Windows	B-Application
is	O
available	O
on	O
Wolfgang	O
Back	O
's	O
website	O
,	O
but	O
a	O
JavaScript	O
emulator	O
also	O
exists	O
.	O
</s>
<s>
The	O
paper	O
computer	O
's	O
method	O
of	O
operation	O
is	O
nominally	O
based	O
on	O
a	O
register	B-Application
machine	I-Application
by	O
Elmar	O
Cohors-Fresenborg	O
,	O
but	O
follows	O
more	O
the	O
approach	O
of	O
John	O
Cedric	O
Shepherdson	O
and	O
Howard	O
E	O
.	O
Sturgis	O
in	O
their	O
Shepherdson	B-Application
–	I-Application
Sturgis	I-Application
register	I-Application
machine	I-Application
model	O
.	O
</s>
<s>
A	O
derived	O
version	O
of	O
the	O
paper	O
computer	O
is	O
used	O
as	O
a	O
"	O
Know-How	B-Application
Computer	I-Application
"	O
in	O
Namibian	O
school	O
education	O
.	O
</s>
