CTOS was a distributed microkernel OS considered to be quite ahead of its time. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8757530160&rd=1&… eBay: Collection of Burroughs B20/BTOS systems, B25, B28, B38 (item 8757530160 end time Feb-02-06 22:57:02 PST)