Bringing back the first computers: The world's greatest restoration projects

Z1 - Stiftung Deutsches Technikmuseum

In the 1930s a 26-year-old German named Konrad Zuse was looking for a way to automate tedious calculations that took up so much of his time as a civil engineer.

Zuse created the Z1, a mechanical calculator that could add, subtract, multiply and divide and was programmable using punched 35mm film tape.

The machine offered many features still found in computers today, such as a control unit, a 64-word mechanical memory, floating-point logic and input-output devices.

The Z1 could handle 22-bit floating point numbers, had a 64-word memory and had nine instructions in its instruction set, which took between one and twenty cycles per instruction to execute.

Numbers were input as decimal numbers, were converted into binary so mathematical operations could be carried out and then converted back into decimal.

The original Z1 was destroyed in a bombing raid on Berlin and Zuse followed it up with further machines, the electro-mechanical Z3 and Z4. He also began work on the world's first high-level language "Plan Calculus".

The Z1 destroyed during the war was reconstructed by a 79-year-old Zuse in 1989, and is on show at the Stiftung Deutsches Technikmuseum in Berlin.

Later on, a team from the museum led by Professor Raul Rojas began a virtual reconstruction of the Z1.

Through the meticulous research of Professor Rojas, a team of his students was able to construct a 3D visual simulation of the Z1's arithmetic unit, which they made available online alongside hundreds of high resolution photos of the machine.

The virtual recreation was the joint winner of the Tony Sale Award. The judging panel said: “Z1 Architecture and Algorithms is a remarkable vision of how such complex artefacts might be delivered to a worldwide audience. It is a project that will undoubtedly give museum curators pause for thought.”

© SDTB / Foto: Frank-Michael Arndt

EAI 680 Scientific Computing System - Analog Museum in Schwalbach, Germany

While most modern computing technology is built around zeroes and ones there was a time computers weren't so binary.

Phenomena in the world aren't restricted to two states, for example the flow of a liquid or strength of a breeze can be strong or weak and eveything in between.

Analog computers used mechanical motion or the flow of electricity to model these real-world nuances.

Analog computers date back to classical antiquity and the Antikythera mechanism but were still being created well into the 20th century, until digital computers, based on electronic switches, became fast enough for software to replicate their functions.

The Analog Museum in Schwalbach, Germany is packed with rescued and restored analog machines, ranging from a table top analog machine made by the BBC to the EAI 680 Scientific Computing System seen here.

Dr. Bernd Ulmann

PRS-4 - Muzem Historii Komputerow i Informatyki

The PRS-4 is a modular 16-bit micromputer, the first of which was built in Poland in 1973.

The machines were used to monitor production in the mining industry, show the movement of trains across the railway network and in a variety of research roles. Only 150 of the machines were produced. They were designed to be compatible with a family of microcomputers produced by Hewlett-Packard at the time.

The restored PRS 4 is on show at the Muzem Historii Komputerow i Informatyki (MHKI) in Katowice, Poland.

PDP-8 - Rhode Island Computer Museum

In 1949, an issue of Popular Mechanics magazine contained a prediction that "computers in the future may weigh no more than 1.5 tonnes". Upon its release in 1963 the Programmed Data Processor (PDP) model 8 made good on that forecast and then some - proving that computers didn't need to be room-sized monsters that only government and big business could afford.

The PDP-8 was about the size of a fridge-freezer and designed to be cheap compared to the multimillion-dollar price of mainframes at the time - selling for about $18,000. It sold an estimated 50,000 units and its success helped popularise the idea of the minicomputer - relatively low-cost computers that could be housed locally and that didn't need to be maintained by a team of trained staff.

Compared to a mainframe, the processing power of the US Digital Equipment Corporation machine was limited - only capable of 12-bit processing, compared to the mainframe's 32-bit processing power. But there were plenty of straightforward tasks like payroll calculation that didn't require the computing power of a mainframe and demand for the PDP-8 saw minicomputers find a home across a range of industries - turning up in factories, offices, banks and laboratories.

The Rhode Island Computer Museum has restored a variety of PDP machines, including a PDP-8/L, PDP-8/I, PDP-9 and PDP-11/44.

Rhode Island Computer Museum (RICM)

Witch-E project

The Witch, or the Wolverhampton Instrument for Teaching Computing, is the world's oldest working stored-program electronic computer.

The Witch was based on telephone exchange relays and 900 Dekatron gas-filled tubes, which could each hold a single digit in memory. Paper tape was used to both input data and store the output of the machine.

The machine was built and used by the Atomic Energy Research Establishment in Harwell, Oxfordshire, and went on to be used as a teaching aid at a college in Wolverhampton until 1973.

It was developed to automate laborious mathematical calculations at the Harwell facility. Witch, also known as the Harwell computer, could solve algorithms at roughly the same speed as a single human mathematician using a mechanical calculator.

Witch-E

The WITCH-E project is building an educational replica of the machine that will allow students to learn from the engineering, math, logic, and computing pricinples used to create the WITCH.

Recreating the WITCH as it was is difficult, the machine requires very high voltages to work and many components used in building the original WITCH are no longer available. The WITCH E aims to replace logical component blocks of the original WITCH design with commonly available 7400 series Transitor-Transitor Logic(TTL) components.

Bull Tabulating Machine - Technikum29 Computer History Museum

The Technikum29 Computer History Museum in Frankfurt am Main, in Germany features machines from throughout history.

Exhibits include mechanical calculators, mainframes, punch card equipment and a variety of analog and hybrid analog-digital computers.

The institution aims to restore every device for visitors to use and learn from.

Shown here is a restored Bull tabulating machine from 1954, which the museum can compute the square root of eight-digit decimal numbers. The machine features 1,500 relays and 10 arithmetic units.

Jim Austin Computer Collection

The final nomination is for the Jim Austin Computer Collection, which brings together machines from the early days of computing to the present day.

Each generation of computer is represented, mechanical, relay, valve, transistor, and all the variations of integrated circuit.

Highlights in the collection include various Cray supercomputers, a huge IBM mainframe and one of the largest collections of Digital Equipment Corporation computers.

The collection, started in 1986, is housed in more than 8,000 square feet of buildings in York in the UK.

Jim Austin