Cray Jedi

Working on the backplane.

I've been working on the restoration of a Cray J90 series parallel vector processing system at RCS/RI (the Retro-Computing Society of Rhode Island.) It was donated by the Brown University Department of Physics where it had been installed in 1996. This was part of a cluster of machines used for high energy and condensed matter theoretical physics research by faculty and students in the department.

The J90 was code-named Jedi during development. Our system is a model J916/8-1024 which designates that it has 8 processors and 1 GB of main memory. The disks have a raw capacity of about 48 GB. The J90 runs UNICOS - Cray's Unix-like operating system. The two SPARC single-board computers in the I/O Subsystem run the VxWorks based IOS-V real-time operating system. The Service Work Station that is used to configure, boot, and manage the Cray is a Sun SPARCstation 5 running Solaris.

We received the donation on June 23, 2014. Since then I've been working with RCS/RI members to install the hardware and configure the operating environment. The list below is an index, in chronological order, of the posts describing the progress that we've made so far. Click on the links to learn more about the Cray and our efforts to restore the system to operational condition.

• The Theory Cluster - July 6, 2014
  The Cray was used at Brown University for theoretical physics research.
• Customer Name (if not confidential) - July 7, 2014
  Moving and reassembling the cabinets.
• Kilowatts, Control Cables, and Cooling - July 8, 2014
  Re-cabling the cabinets and preparing for installation.
• Under the Covers - July 10, 2014
  A look inside the system.
• System Ready - July 12, 2014
  Applying power and checking for faults.
• bootp - July 15, 2014
  Building the console workstation and I/O subsystem.
• Jedi vs. the Droids - July 17, 2014
  Comparing the performance of a J90 to modern devices.
• Power Up - July 21, 2014
  Configuring the I/O subsystem.
• Silicon to Supercomputer - July 29, 2014
  A look at the chips in the J90 processor and memory modules.

Powered up with a glowing system ready light

I'll update this page frequently as the project progresses. Entries related to the project are tagged with the label Cray Jedi. Photos on this page by Dave Fischer.

Note: many of the photos used to illustrate my blog posts were taken with a phone while I was working on the system and the image quality is not the best. Dave will be doing photo shoots to produce higher quality images while the project continues.

We also post updates about our activities on social media sites. Follow us at:

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RCS/RI holds a public open house from 1-8 pm on the third Saturday of each month at our facility in Providence, RI.