Cray-1 by Daryl Brach

Cray-1 by Daryl Brach

Original Project Log: Here
Foreword by Antony Leather

The Blue Gene and Cray XT5 are the current otherworldly, number crunching leviathans, endlessly working away in fields such as climate modelling and astrophysics. Variants of each reside in the current top ten fastest supercomputers on the planet. Back in the late 1970s, though, the Cray-1, the first supercomputer built by Cray Research, was the supercomputer to have.

Despite Cray Research only selling eighty or so Cray-1s, the lasting memory most people have of this iconic machine is the classic design of its case. It housed not only the 5.5 tons and millions of pounds worth of computer hardware but also a refrigeration system.

The design has certainly stuck in forum user Pfaffen's (aka Daryl Brach) mind, as he set about replicating the shape of the Cray-1 and of course, building his own system inside it. With six other fantastic wooden wonders to his name (World Map, Canary Mesa, Fibonacci, Vogel Haus, and the four Hokusai cases), we were interested to see what he could come up with. It's over to Daryl for an eye candy-rich walk through of this brilliant scratchbuild.

Introducing the Cray-1

I had the idea to create a scale model of a truly exceptional computer, one of the first supercomputers, the Cray-1. It was created to solve 'Tomorrow’s Problems Today', weather forecasting and climatology, petroleum research, structural analysis and nuclear research to name a few.

It was designed to preserve user’s investment in the FORTRAN programming language (IBM Mathematical Formula Translating System) and take advantage of the Cray-1’s vector processing capabilities.

The most powerful Cray-1 was the Model S/4400 with a maximum of 4 million 64-bit words of central memory, four I/O processors and 8 million words of buffer memory.

All the processing power was accomplished with 200,000 integrated circuits, 3,400 printed circuit boards, 60 miles of wire, and housed in less than 70 square feet of space.


I visited the Smithsonian Museum in Washington D.C. to see the Cray-1 Supercomputer on exhibit. Serial #14 ran from 1978 to 1983 for the National Center for Atmospheric Research (NCAR) in Boulder, Colorado and was donated to the Smithsonian in 1986.


The trip served to answer a number of lingering questions about its design, construction and aesthetics. I noticed, as I took pictures and compared what I saw with what I had read, how remarkable this computer was and how brilliant the people who designed and built it nearly 40 years ago, actually were.

I thought about building a complete system in each of the 12, full size, vertical fins in keeping with the design of the original, or perhaps a single system. However, I decided on building two full systems in the bottom section which is where the large refrigeration system was housed in the real Cray-1's.