<s>
The	O
Z4	B-Device
was	O
arguably	O
the	O
world	O
's	O
first	O
commercial	O
digital	O
computer	O
.	O
</s>
<s>
The	O
Z4	B-Device
was	O
Zuse	O
's	O
final	O
target	O
for	O
the	O
Z3	B-Device
design	O
.	O
</s>
<s>
Like	O
the	O
earlier	O
Z2	B-Device
,	O
it	O
comprised	O
a	O
combination	O
of	O
mechanical	O
memory	O
and	O
electromechanical	O
logic	O
,	O
so	O
was	O
not	O
a	O
true	O
electronic	O
computer	O
.	O
</s>
<s>
The	O
Z4	B-Device
was	O
very	O
similar	O
to	O
the	O
Z3	B-Device
in	O
its	O
design	O
but	O
was	O
significantly	O
enhanced	O
in	O
a	O
number	O
of	O
respects	O
.	O
</s>
<s>
The	O
memory	O
consisted	O
of	O
32-bit	O
rather	O
than	O
22-bit	O
floating	B-Algorithm
point	I-Algorithm
words	O
.	O
</s>
<s>
The	O
Program	O
Construction	O
Unit	O
(	O
Planfertigungsteil	B-Device
)	O
punched	O
the	O
program	O
tapes	O
,	O
making	O
programming	O
and	O
correcting	O
programs	O
for	O
the	O
machine	O
much	O
easier	O
by	O
the	O
use	O
of	O
symbolic	O
operations	O
and	O
memory	O
cells	O
.	O
</s>
<s>
Numbers	O
were	O
entered	O
and	O
output	O
as	O
decimal	O
floating-point	B-Algorithm
even	O
though	O
the	O
internal	O
working	O
was	O
in	O
binary	O
.	O
</s>
<s>
In	O
1944	O
,	O
Zuse	O
was	O
working	O
on	O
the	O
Z4	B-Device
with	O
around	O
two	O
dozen	O
people	O
,	O
including	O
Wilfried	O
de	O
Beauclair	O
.	O
</s>
<s>
To	O
prevent	O
it	O
from	O
falling	O
into	O
the	O
hands	O
of	O
the	O
Soviets	O
,	O
the	O
Z4	B-Device
was	O
evacuated	O
from	O
Berlin	O
in	O
February	O
1945	O
and	O
transported	O
to	O
Göttingen	O
.	O
</s>
<s>
The	O
Z4	B-Device
was	O
completed	O
in	O
Göttingen	O
in	O
a	O
facility	O
of	O
the	O
Aerodynamische	O
Versuchsanstalt	O
(	O
AVA	O
,	O
Aerodynamic	O
Research	O
Institute	O
)	O
,	O
which	O
was	O
headed	O
by	O
Albert	O
Betz	O
.	O
</s>
<s>
In	O
1949	O
,	O
the	O
Swiss	O
mathematician	O
Eduard	O
Stiefel	O
,	O
after	O
coming	O
back	O
from	O
a	O
stay	O
in	O
the	O
US	O
where	O
he	O
inspected	O
American	O
computers	O
,	O
visited	O
Zuse	O
and	O
the	O
Z4	B-Device
.	O
</s>
<s>
When	O
he	O
formulated	O
a	O
differential	O
equation	O
as	O
a	O
test	O
,	O
Zuse	O
immediately	O
programmed	O
the	O
Z4	B-Device
to	O
solve	O
it	O
,	O
Stiefel	O
decided	O
to	O
acquire	O
the	O
computer	O
for	O
his	O
newly	O
founded	O
Institute	O
for	O
Applied	O
Mathematics	O
at	O
the	O
ETH	O
Zurich	O
.	O
</s>
<s>
In	O
1954	O
,	O
Wolfgang	O
Haack	O
tried	O
to	O
obtain	O
the	O
Z4	B-Device
for	O
the	O
Technical	O
University	O
of	O
Berlin	O
,	O
but	O
it	O
was	O
instead	O
transferred	O
to	O
the	O
(	O
ISL	O
,	O
Franco-German	O
Institute	O
of	O
Research	O
)	O
in	O
France	O
,	O
where	O
it	O
was	O
in	O
use	O
until	O
1959	O
,	O
under	O
its	O
technical	O
head	O
Hubert	O
Schardin	O
.	O
</s>
<s>
Today	O
,	O
the	O
Z4	B-Device
is	O
on	O
display	O
in	O
the	O
Deutsches	O
Museum	O
in	O
Munich	O
.	O
</s>
<s>
The	O
Z4	B-Device
inspired	O
the	O
ETH	O
to	O
build	O
its	O
own	O
computer	O
(	O
mainly	O
by	O
Ambros	O
Speiser	O
and	O
Eduard	O
Stiefel	O
)	O
,	O
which	O
was	O
called	O
ERMETH	B-Device
,	O
an	O
acronym	O
for	O
(	O
"	O
Electronic	O
Computing	O
Machine	O
ETH	O
"	O
)	O
.	O
</s>
<s>
In	O
1950/1951	O
,	O
the	O
Z4	B-Device
was	O
the	O
only	O
working	O
digital	O
computer	O
in	O
Germany	O
,	O
and	O
the	O
second	O
digital	O
computer	O
in	O
the	O
world	O
to	O
be	O
sold	O
,	O
beating	O
the	O
Ferranti	B-Device
Mark	I-Device
1	I-Device
by	O
five	O
months	O
and	O
the	B-Operating_System
UNIVAC	I-Operating_System
I	O
by	O
ten	O
months	O
,	O
but	O
in	O
turn	O
being	O
beaten	O
by	O
the	O
BINAC	B-Device
(	O
although	O
that	O
never	O
worked	O
at	O
the	O
customer	O
's	O
site	O
)	O
.	O
</s>
<s>
Notable	O
are	O
the	O
Z11	B-Device
,	O
which	O
was	O
sold	O
to	O
the	O
optics	O
industry	O
and	O
to	O
universities	O
,	O
and	O
the	O
Z22	B-Device
.	O
</s>
<s>
In	O
1955	O
the	O
Z4	B-Device
was	O
sold	O
to	O
the	O
French-German	O
Research	O
Institute	O
of	O
Saint-Louis	O
(	O
Institut	O
franco-allemand	O
de	O
recherches	O
de	O
Saint-Louis	O
)	O
in	O
Saint-Louis	O
,	O
close	O
to	O
Basel	O
,	O
and	O
in	O
1960	O
transferred	O
to	O
the	O
German	O
Museum	O
in	O
Munich	O
.	O
</s>
<s>
The	O
Z4	B-Device
was	O
used	O
for	O
calculations	O
for	O
work	O
on	O
the	O
Grande	O
Dixence	O
Dam	O
.	O
</s>
<s>
Approximately	O
1000	O
floating	B-Algorithm
point	I-Algorithm
arithmetic	I-Algorithm
operations	O
on	O
average	O
an	O
hour	O
.	O
</s>
