The following is a portrait and story of our Cray-1 Supercomputer (serial number 38) which came from Livermore National Laboratories in Livermore, California. This system was in use in Livermore Labs from the early 1980s and was sold at auction in 1993 to memorabilia collector and reseller Tony Cole. Tony sold boards from this unit for ten years or so, doing a fine job mounting them in lucite and selling them on eBay. In 2001 DigiBarn Curator Bruce Damer purchased one of these boards and then contacted Tony asking him what he was going to do with the whole unit that remained. Some months later Bruce and Tony made an agreement to move the unit and another of his Crays, the Q2, from their temporary location at the Computer History Museum's Moffett Field "dense storage" facility to the DigiBarn in time for our grand opening in 2002. In 2005 Bruce completed the transaction with Tony to acquire the Cray 1, the Cray Q2 and a number of other artifacts related to the Cray X-MP and Cray 3. It might also be of interest that at the same time as this Cray was in service, another Cray in another building at Lawrence Livermore Labs appeared in the film "Tron" (which was animated on a Cray 1). The main characters were purportedly filmed running through Lawrence Livermore Labs and pass by this machine. Another interesting thing was that despite having most of the original boards removed by Tony, the government typically released Cray and other computers of its class with no or a single column of boards to prevent it being used again (you need at least two columns in place to use a Cray-1). Therefore through happy coincidence, this Cray is actually of museum/collector calibre. A number of the removed boards were provided by Tony. You might be interested in our other Cray artifacts.
The "guts": Wiring and Boards
The wiring and boards were assembled in Chippewa Falls, Wisconsin in the USA and key members of the manufacturing crew included women skilled in weaving and the other fabric arts. These women would work in teams to do the amazing job of wiring the backplane of this machine. You can see from the photos below how densely packed this wiring is. Seymour Cray chose these women for their skill level, patience and perfectionist tendancies. Wiring comes in lengths of 1, 2 and 4 feet, corresponding to 1, 2, and 4 nanosecond delays for signals to propagate between and through the boards in the processor columns. The piping fixtures were for the freon cooling of the boards (coolant would run up and down the "fins" drawing heat from the edges of the copper-substrate boards. Each Cray-1 contained over 3,000 boards. A full height subfloor (so that a person could walk in underneath) was required to service the unit. The transformers (wedges with naugahyde (tm) over plywood coverings) were fed by power from the Power Distribution Unit (PDU) which in turn was fed by a deisel generator set. The processor tower itself was loaded and unloaded with numeric calculations by a large supporting general purpose computer such as a CDC 7600 (also designed by Seymour Cray).
The Power Distribution Unit (PDU)
The Power Distribution Unit is a cabinet about 7 feet tall that distributes power to the transformers (the "bench seat" like wedges at the base of the processor tower. Our PDU records that the Cray was powered up for just about 67,941 hours. Voltage levels can be set for individual power lines to the transformers.
Know anything more about the Cray 1 Supercomputer? Contact Us!
Please send site comments to our Webmaster.
Please see our notices about the content of this site and its usage.
(cc) 1998- Digibarn Computer Museum, some rights reserved under this Creative Commons license.