Most stories in the history of computing took place in one of a small number of places. The wartime code-breaking effort in Bletchley Park led to Colossus, the first programmable electronic computer. Various university campuses in Britain and the US were home to first-generation computers like ENIAC, EDVAC and the Manchester Baby in the late 1940s. Silicon Valley then stole the limelight with the home computer revolution in the 1970s. Naturally, all of these places have their museums celebrating their local achievements, but the world’s largest computer museum is not found in Silicon Valley or on the campus of a famous university. Instead, you have to travel to a small German town called Paderborn, which houses the Heinz Nixdorf Museumsforum, or HNF.

Heinz Nixdorf might not be a household name in America like Jack Tramiel or Steve Jobs, but he was one of Europe’s great computer pioneers. Starting with vacuum tube based machines in 1952, Nixdorf gradually expanded his company into one of the largest computer manufacturers of the 1970s. His products were especially popular among large businesses in the financial sector, such as banks and insurance companies. By the late 1980s however, sales went downhill and the company was eventually acquired by Siemens. Today, the Nixdorf name lives on as part of Diebold-Nixdorf, a major producer of ATMs and checkout machines, reflecting the original company’s focus on the financial industry.

The museum’s roots lie in Heinz Nixdorf’s personal collection of typewriters and other office equipment. Although he already envisioned starting a museum dedicated to computing, his sudden death in 1986 put a stop to that. A few of his employees kept the plan alive however, and in 1996 the HNF was opened in Paderborn. Today the museum is run by a non-profit foundation that aims to provide education in information and communication technology to a wide audience.

The collection is housed in the former worldwide headquarters of Nixdorf Computer AG, a rather imposing 1970s office building covered in gold-tinted windows. Inside,]] you’re reminded of its former life as an office building through its compact layout and low ceilings. It does give the museum a bit of a cosy feel, unlike, say, the cavernous halls of London’s Science Museum, but don’t let this fool you: at 6,000 m², the main exhibition area is about twice as large as that of Silicon Valley’s Computer History Museum.

First floor: The Basics of Communication and Calculation

The main exhibit begins with artifacts dating back 5,000 years: clay tablets from Sumeria show how ancient people recorded their thoughts, kept inventories and performed calculations. Devices like the abacus and the quipu from South America show how physical devices can help with arithmetic, which is otherwise a completely abstract science. Writing evolved through a series of different media into the printing press, making written materials available to more people than ever before.

These twin concepts of calculation and communication are carried forward throughout the exhibition. On one side of the hall, various printing techniques show the way to the invention of the typewriter, of which the museum has an impressive collection. On the other side, abacuses evolve into complex mechanical calculators.

Sholes & Glidden introduced the familiar QWERTY layout on their typewriters in the 1870s.

Flip those levers and turn those cranks: mechanical calculators can add, subtract, multiply and divide without electricity.

If you’ve never laid your hands on one of these machines filled with cams, cranks and levers, then here’s your chance. A helpful computer screen explains all the various steps needed to reset the calculator, dial in the inputs and set the gears in motion to obtain the desired result. The whirr of the gears and the clacking noise of the decimal displays give an indication as to how much work really needs to be done in order to perform even a simple calculation.

The HNF has made great use of modern technologies to bring its ancient artifacts to life. For example, an interactive exhibit links an abacus to a computer display that shows the state of the beads in real time, giving the user immediate feedback on their actions. But by far the most eye-catching piece of modern tech on this floor is PETRA, a steampunk-style robotic guide: ask her about a specific exhibit and she will physically lead you there and tell the artifact’s story on her integrated display.

An extensive Hall of Fame celebrates the contributions of fifteen pioneering scientists and engineers who laid the foundations for the development of information technology. Among them are Wilhelm Schickard, Blaise Pascal and Gottfried Wilhelm Leibnitz who invented the first calculating machines; Charles Babbage and Ada Lovelace who developed these concepts further into programmable computers; and Alan Turing and John von Neumann who laid the theoretical foundations of information science.

Petra will gladly guide you to specific exhibits and tell you all about them.

Petra will gladly guide you to specific exhibits and tell you all about them.

One impressive piece of kit towards the end of the first floor is a fully-functioning relay-based telephone exchange. In front of it are several different telephone models, all connected into a local phone system. You simply pick up one receiver, dial the number of another, hear it ring, and wait for someone to pick it up and talk to you. The most interesting thing goes on right in front of you however: as your phone sends pulses down the line, you can hear the relays clicking and routing your call in real time. Even kids who grew up with smartphones love playing with these phones (“can you hear me?” “yes, I can hear you too!”), although visitors born after 1990 or so might need some instruction first on how to use that weird spinning disk to enter a number.

Second Floor: From Big Iron to Pocket-Sized Gadgets

The second floor is where items begin to appear that most people will recognize as computers. Many of the oldest devices here were made in Germany by the likes of Zuse and Siemens, and processed data using relays and vacuum tubes while storing data on punched cards. These devices often took up entire rooms; one corner houses a typical setup of the ESER 1055, an East German clone of the IBM System/360 mainframe.

Wandering along those racks full of handmade circuit boards gives you a good sense of the enormous advances that were made in the first few decades of the computer era: the processing power of all that hardware barely comes close to that of a 1990s era desktop PC.

The Zuse Z11 from 1956 had 1,665 relays and could perform five additions per second.

Designed in 1963, the fully transistorized D4a was aimed at scientists and engineers.

Speaking of PCs, what was the first personal computer? While the Altair 8800 from 1974 might pop up in the minds of many, an engineer from the former East Germany who once visited the museum claims that his design, the D4a from 1962, should rightfully have that title. After all, it was a programmable calculating device that could store data, was meant for use by one person, and could fit on a (sturdy) desk. With just 200 transistors it managed to perform about 2,000 operations per second, and could store 4,096 words, each 33 bits wide, on its magnetic drum memory.

Several corners of the museum are dedicated to the social aspects of computing. The history of the office is described in detail, from medieval desks where monks copied Bibles to modern remote working via video link.

Another interesting social concept linking computing and communication is that of cryptography. The museum has two original Enigma machines, as well as several other cryptographic machines from various countries. A separate display case contains artefacts related to the hacking and phreaking scene, including an original Cap’n Crunch whistle – the one that emitted the famed 2600 Hz frequency that could be used to make free long-distance phone calls in the 1970s. Especially noteworthy are several artefacts belonging to the Chaos Computer Club, one of the oldest hacker collectives still in existence. Founded in West Berlin in 1981, the CCC became famous for breaking into banking systems in the 1980s, and for other rebellious acts like distributing modems that enabled German computer users to go online, at a time when connecting unauthorised devices to the phone network was strictly prohibited.

The world’s most famous codebreaker, Alan Turing, is also featured prominently, with one of the two Enigmas located in his booth. But he is of course also known for the Turing machine, the abstract model of a general computing device that carries his name. To illustrate its working principle, the HNF commissioned an electromechanical Turing machine model that visitors can experiment with.

The section titled “Computers for everyone” contains home computers and professional PCs from the 1970s to the 1990s. It’s a comprehensive collection of all big names from that era: the Commodore PET, the Apple Lisa, IBM’s Personal Computer, and of course the most expensive exhibit of all: a working Apple I. In fact, most of these computers are still working and are demonstrated during special events. At other times you can still try out their software in one of several emulator booths.

The Turing machine moves data between cells according to its program.

The 1974 Altair 8800 is often considered the first true personal computer.

TI or HP? Sharp or Casio? Algebraic or RPN? LED, VFD or LCD? They’re all here.

Just a decade later, all of this could fit in your pocket.

Where the first floor featured mechanical calculators, the second floor has electronic ones. And not just a few, either: a huge display case shows more than 700 different types dating from the 1960s to the late 1990s. If you went to school in those days, chances are good you’ll find the one you used somewhere in this collection. Again, all big names are represented: the early Canon Pocketronic, the scientific HP-35, the Sharp PC-1210 running BASIC, and the TI-84 and Casio Fx series graphing calculators that are still popular today.

Right next to the calculator wall is an exhibit that shows what a simple four-function calculator would look like if one were to build it using technology available in the 1960s. Instead of an integrated circuit it has a massive stack of circuit boards with hundreds of discrete transistors; instead of a low-power LCD screen it has a nixie tube display. It performs calculations in exactly the same way as a pocket calculator, although at much slower speed. So slow in fact, that you can track the flow of digits inside its circuitry in real time. This beautiful exhibit was made by the same egineer who also made the modern re-creation of the Elektronensaldierer ES 24.

Towards the end of the main exhibition area is a section dedicated to robotics and artificial intelligence. Fans of Claude Shannon will be pleased to find a recreation of Theseus, Shannon’s electro-mechanical maze-navigating mouse robot.

A more modern type of AI is implemented in Nadine, a human-like robot that can have a conversation with you, although on our visit she struggled to provide answers more useful than “I don’t know about that”; you’re probably going to have a more meaningful conversation with the voice assistant inside your smartphone. Then again, Nadine was built in 2013, which makes her a bit of a dinosaur in computer years.

Also present are several classic home robots from the ’80s and ’90s like Omnibot and Aibo, as well as numerous types of industrial robots. One called Beppo spends all day sweeping its enclosure with a broom, occasionally interacting with visitors. Naturally, you can also get your portrait drawn by Vincent, the one-armed pen-wielding robot artist.

The HNF does not disappoint when it calls itself the world’s largest computer museum: even spending a full day inside isn’t enough to fully appreciate its vast collection. But calling it simply a computer museum does not fully do it justice, as its collection covers way more than just computers. Whether you’re into telecoms gear, cryptography, the social aspects of information technology or the fundamentals of programming, there’s bound to be some corner of the museum that will have you hooked.

Knowledge of German is not required to appreciate the museum as most exhibits have bilingual German and English descriptions. For the few that don’t, any mobile translation app should be able to help; if you’re still confused, the museum’s human and robot staff are always on hand. In short, the HNF is definitely worth visiting if you’re in the area, and at just eight euros per adult it’s an absolute bargain as well.