Spanish Museum Builds Cray-1 Supercomputer Replica Using 30 Mac Minis

Cray-1 Replica Unveiled

The Museo de Historia de la Computación in Spain has unveiled a 1:1 scale visual replica of the Cray-1 supercomputer, originally from 1976. This project, developed over 18 months, also serves as a tribute to the 50th anniversary of the Cray-1 and Apple’s founding.

Hardware and Performance

The replica is powered by 30 2012-era Mac Minis, with two units from 2014. Five of these are quad-core i7s, and the remaining 25 are dual-core i5 models. When networked, the system achieves 1.3 teraflops of performance using 64 active processing cores, benchmarked with a custom Python script for matrix multiplication. The museum previously recorded 1.5 teraflops with all 70 cores before one node went offline.

The original Cray-1 had a peak theoretical performance of approximately 160 megaflops, highlighting the significant increase in computing power available in consumer hardware today.

Software and Architecture

Instead of a standard Linux distribution, the team used macOS Mojave (10.14) due to its built-in support for MPI (Message Passing Interface). MPI allows the individual Mac Mini nodes to communicate and distribute tasks across the cluster.

The replica demonstrates a parallel processing architecture, distributing work across independent processors, in contrast to the original Cray-1's vector processing approach, which applied a single instruction to multiple data elements simultaneously.

Cooling and Display

To manage heat and noise in a museum setting, the team implemented passive convection cooling. This was achieved using a steel rack chassis and aluminum tray mounts for each Mac Mini, avoiding the loud fan cooling typical of server environments.

Museum visitors can observe the system in real time as it executes matrix algorithms, visualizing the performance scale from a single core to the full parallel suite.