We would all like a real computer - one with flashing lights, switches and tape drives rocking back and forth. But what about a working Cray-1A? Well if you have the time and determination - it's possible.

Chris Fenton is interested in old computers - perhaps a bit more interested than the average computer enthusiast. He has spent a year and a half building a 1/10th scale working model of the Cray 1-A. This is complete with a case that looks like the original complete with bench seats that once held the power supplies etc.

But this is no ordinary model. It really is a working Cray 1-A and should in theory at least run original Cray 1-A programs.

The basic of the model is a Xilinx Spartan 3E 1600 development board which is basically a very big FPGA (Field Programmable Gate Array) and this means that the hardware can be programmed to do any job you care to specify.

Now you might be just beginning to guess at how crazy and wonderful this venture really is. Chis implemented a real working model of the Cray 1-A running at about 33MHz (the original ran at 80MHz). It also misses a few features - context switching, I.O channels (who has any Cray I/O devices) and interrupts.

Wonderful stuff! - Chris' only problem is that he can't find any original Cray software to run on the model. Apparently it has all been destroyed or classified. So if you know of a dark place where spies hoard old Cray software let Chris know.

All photos are by Chris Fenton.

More Information

http://chrisfenton.com/homebrew-cray-1a/

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