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Manufacturer Cray
Identification,ID Cray-Y-MP
Date of first manufacture-
Number produced -
Estimated price or cost-
location in museum -
donor -

Contents of this page:

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Special features

Historical Notes

This Artifact

Interesting Web Sites

Other information
How to boot an FPGA simulation?

COS 1.17 disk image for Cray-1/X-MP

This disk contains a backup of the last remaining copy of the Cray Operating System, the original operating system for the Cray-1 and Cray X-MP supercomputer line. The disk likely contains a binary image of COS 1.17 (the last revision of of the OS), as well as other unknown software, and initially belonged to a single-processor Cray X-MP machine. The disk was written in 1989. The machine's I/O Subsystem (IOS) would have likely booted from this disk, and then loaded the OS into main CPU memory. This was recovered from a CDC 9877 80 Megabyte disk pack, formatted with 5 heads/cylinder, 808 tracks, 512B/sector, 32 Sectors/track (~64 Megabytes after formatting).

We need help deciphering the file system of the image in order to bring us closer to finally being able to boot our FPGA-based Cray-1 ( If you make any progress / are interested in helping, contact Chris Fenton ( and help us bring back the Cray-1!

If you have comments or suggestions, Send e-mail to Ed Thelen

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