The Computer History Museum in Spain has unveiled a 1:1 scale visual replica of the famous Cray-1 supercomputer from 1976. Instead of looking for expensive, cutting-edge technology to run the system, the creative team powered the project with 30 2012-era Mac Minis. Developed over 18 months, the project serves as a tribute to the 50th anniversary of Cray-1 and the founding of Apple.
Mac Minis from more than a decade ago may not seem like the obvious first choice for building a clustered supercomputer, but when networked, developers can orchestrate the 64 active processing cores at a combined performance of 1.3 teraflops in their most recent tests. The museum reportedly achieved 1.5 teraflops previously using all 70 available cores, before one node went offline. Benchmarks were obtained using a custom matrix multiplication Python script. Five PCs are quad-core i7 and the remaining 25 are dual-core i5 models. With the exception of two units from 2014, the rest of the set dates from 2012.
The replica is a valuable tool for museum visitors to understand changes in computer architecture since 1976. The original Cray-1 used vector processing, applying a single instruction to multiple data elements simultaneously, while the replica distributes work among independent processors in a parallel cluster. The maximum theoretical performance of the original Cray-1 was approximately 160 megaflops. What was originally a purpose-built research machine has been recreated with consumer hardware that is far more capable than the machine that inspired it.
Instead of opting for a more standard Linux distribution, the team found that macOS Mojave (10.14) met their project’s needs by taking advantage of macOS’s built-in support for MPI (Message Passing Interface), the software layer that allows all nodes in the cluster to pass tasks between each other.
The Cray-1 replica, complete with the iconic padded bench. The only thing missing is for Robert Redford and Ben Kingsley to talk about SECTEC astronomy. Credit: Computer History Museum
Credit: Computer History Museum
The Cray-1 replica, complete with the iconic padded bench. The only thing missing is for Robert Redford and Ben Kingsley to talk about SECTEC astronomy. Credit: Computer History Museum
Credit: Computer History Museum
Visitors to the Computer History Museum can observe in real time how the system executes matrix algorithms, mapping the scale of system performance from a single core to the entire array running in parallel.
Stealth supercomputing
Combining 30 consumer PCs into a working cluster wasn’t the only engineering challenge the team faced. If you’ve ever walked into a server room or, like me, foolishly installed one in your own basement, you’ll know that fan cooling can be high. The museum team used passive convection cooling through a steel frame chassis and aluminum tray supports for each Mac Mini. Compared to the din of a modern data center, this group is almost inaudible.
