Help [Chris] boot his Cray-1 supercomputer

[Chris Fenton] needs your help. After constructing a 1/10th scale, cycle accurate Cray-1 supercomputer and finding a disk with Cray software on it, he’s ready to start loading the OS. There’s a small problem, though: no one knows how to boot the thing.

[Chris] posted a disk image for a Cray-1/X-MP with the help of the people at archive.org. Now he needs your help – if you think you can reverse engineer the file system, [Chris] will pay handsomely with a miniature model of a Cray printed on his MakerBot. In any case, it seems like a fun challenge.

From our quick glance at the disk image with a HEX editor, it looks like [Chris] has something special on his hands. We see a few references to “Cray memory and registers,” as well as “IOP-0 Kernel, Version 4.2.2″ in the header along with a few dates referencing July of 1989.  This is consistent with the history of the source disk pack. If you think you’ve got what it takes to reverse engineer the file system of a Cray-1, this is your chance.

Recovering data for a homemade Cray

In our hubris, we pat ourselves on the back when we’re able to pull data off our old SCSI drives. [Chris Fenton]‘s attempt to get an OS for a homebrew Cray-1 puts us rightfully to shame.

Last year we saw [Chris]‘ fully functional 1/10th scale Cray-1 supercomputer built around FPGA. While the reproduction was nearly cycle-accurate, [Chris] hasn’t had an opportunity to test out his system because of the lack of available Cray software. A former Cray employee heard of his plight and loaned an 80 Megabyte CDC 9877 disk pack to in the hope of getting some system software.

[Chris] acquired a monstrous 100 pound disk drive to read the disk pack, but after 30 years in storage a lot of electrical problems cropped up. Since reading the drive digitally proved to be an exercise in futility, [Chris] hit upon the idea of taking analog data straight from the read head. This left him with a magnetic image of the disk pack that was ready for some data analysis.

After the disk image was put up on the Internet, the very talented [Yngve AAdlandsvik] figured out the data, header, and error correction formats and sent [Chris] a Python script to tease bits from the analog image. While no one is quite sure what is on the disk pack provided by the Cray employee, [Chris] is remarkably close to bringing the Cray-1 OS back from the dead. There’s also a great research report [Chris] wrote as penance for access to the CDC disk drive. Any Hack A Day readers feel like looking over the data and possibly giving [Chris] a hand?

Tiny Cray-1 courtesy of an FPGA

[Chris Fenton] spent a year and a half constructing a 1/10th scale Cray-1 reproduction. The famous supercomputer was meticulously modelled in a field programmable gate array for a “nearly cycle-accurate” reproduction. [Chris'] hardware of choice for the project is a Xilinx Spartan-3E 1600 development board, using 75-80% of the available resources. The finished product runs at 33 MHz and is missing a few functions but it sounds like they don’t affect code execution. We like that he didn’t stop with the processor implementation, but also took the time to produce a case for the development board that looks just like the original.

Unlike the Atari 2600 FPGA project, we’re not quite sure what we’d use this for. But that doesn’t diminish the excellence of his work.