machine had been destroyed by the bombs of World War II). Representing one of the highlights of the Deutsches Museum, the Z3 is still demonstrated to visitors. Located near the Dehomag/ IBM plugboard programmed punched card tabulating machine D11, the pioneer machines of Konrad Zuse also mark the middle of the exhibition in a technohistorical sense. Zuses’s machines separate the historical mathematical instruments, the mechanical calculators, and sequence controlled historical automatons in the first part of the exhibit from the spectrum of the big, middle, and small real computers in the second part of the exhibit.

One main issue is the separation of analog and digital calculating instruments and machines. The contrast is highlighted by red text tables for all explanations on analog technology, and by blue tables for all texts on digital technology. One of the outstanding early analog calculating instruments is the exceptionally big astrolabium, made by Erasmus Habermel in 1588. A showcase with different modern slide rulers, mainly used by engineers until the 1970s, is a logical follow-on. This part of the exhibition also includes a big and unique collection of mechanical planimeters, and some components of several big mechanical and electronic analog computers.

The blue-marked part with digital instruments and calculators begins with a small collection of different abaci. A historical sequence of selected mechanical digital desk calculators starts with Wilhelm Schickard’s reconstructed machine, and is continued by replicas of the machines of Blaise Pascal and Gottfried Wilhelm Leibniz, all designed during the 17th century. Particularly valuable is an original calculator, made by Anton Braun and Philippe Vayringe and presumably completed around 1735. Beside these historical unique specimens one can view the broad spectrum of the mechanical calculators, industrially produced in series, beginning with C.X Thomas and ending with the sophisticated Friden-Model SRW 10. Many of the mechanical calculators were still used in the 1970s. A special cabinet on the cryptology is presented as a part of the digital calculating exhibit—here not with digits but with letters. Visitors find several coding machines, includ-

the fundamental idea
involves presenting
the newest
“masterpieces” as
a logical and
historical extension
of their precursors.

ing two Enigmas. Some historical sequence controlled automatons are also shown as a part of the prehistory of the computer, one of them the famous mechanical trumpeter, made by Friedrich Kaufmann in 1810.

In the second half of the exhibition with real computers, the gigantic central processing unit of the UNIVAC I Factronic with its mercury delay line memory is particularly representative. Visually it is overshadowed a bit the so-called PERM computer ( Pro-grammgesteuerte Elektronische Rech-enanlage München) with its magnetic drum memory, which has been built at the Technical University Munich as a scientific project financed by the Deutsche Forschungsgemeinschaft (German Research Foundation) from 1950 until 1956. The UNIVAC computer, which was used at the Battelle-Institute at Frankfurt/Main between 1956 and 1963, represents the start of industrially produced computers in the U.S., whereas the PERM represents the beginning of research and development of electronic computers at German universities. Also interesting are some original parts of the U.S. pioneer computers ILLIAC and ORACLE. Several computers, developed and produced by the then West German industry are included in the gallery. With the exception of the vacuum tube machine Z22, produced by the Zuse KG in 1958, they all were designed on the base of discrete semiconductor elements.

Also presented is a Cray I from
1983, which until the end of Cold War
in 1990 had its completeness checked
for the COCOM-office (Coordinating
Committee on Multilateral Export Con-
trols) by an employee of the company.
Several office computers produced by
the companies Nixdorf, Kienzle, and
Siemag/Philips, as well as several very
early personal computers and elec-
tronic pocket computers are displayed
at the end of the exhibition.

hartmut Petzold ( [e-mail]) is the former curator for mathematical instruments, compilers, and time measurement at the deutsches museum in munich, germany.

u.s. national museum
of american history
David K. Allison

The U.S. National Museum of American History has collected and preserves more than three million artifacts that document the history of the American people. These range from the original “Star-Spangled Banner” and Abraham Lincoln’s top hat to Alexander Bell’s telephone prototypes. The museum’s collections form a mosaic of American life and comprise the nation’s greatest single collection of historical objects.

The Division of Information Technology and Communications is one of eight curatorial divisions in the museum. Collections in the Division include computing, mathematics, electricity, printing, graphic arts, photography, and numismatics. The Computing Collection has approximately 2,000 objects in the following categories: supercomputers and components; mainframe computers and components; minicomputers and components; microcom-puters and components; electronic calculators; analog computers; computer