MERAC

The effort rebuild early computers truely requires significant effort which is in most cases not available. So demonstration objects are a good choice to show the essentials of a historic machine. A mock-up controlled by a modern computer is very cost-efficient, but lacks the flair of authenticity.

Electro-mechanical Solutions (with electro-magnets and relays) are attractive, as they can be build rather simple, because conections by electical lines are robust and easy to prepare. The result is transparent and in so far authentic, as it works by itself.

Looking back, it is clear that already early in the 20th century, when relays were available in large quantities for telephone exchanges, a programmable Computer could have been built with moderate effoert. To prove this thesis, I have designed simple, programmable computers, which are easy to build.

The first device, which was shown for the first time on the VCFB 2017 (Vintage Computer Festival Berlin), is based on my studies of the Analytical Engine (Babbage), the ENIAC (Mauchly & Eckard), and others. It is a minimal version just to check the concept, and does not yet provide automatic programming:

However, using this gadget, the commonalities and differences to early computers can be described better than by words and diagrams.

I have already learned:

• A good artisan for pipe organs could have build such a computer purely mechanical before Babbage
• The use decimal numbers with unary coded digits (number of pulses) is inefficient if a feasible binary memory is available
• Storage technology is dominant for the capabilities of a computer

There is now an english version of the MERAC technical description an the Summary (and a tiny film: )