The Jupiter (KC-10 processor) was physically very large, and designed to use the next generation(s) of DEC peripherals. It was implemented using technology similar to the KL-10, with a CI bus to HSC-50s. It was supposed to be a lot faster, but failed to meet specs. The Toad-1 System was the result of Len Bosack's suggestion in the mid 1970s (as the KL-10 was going out the door) that DEC should build "a 10 On A Desk." It was not originally intended to be a server. (This was the original product plan of cisco Systems, by the way. TCP/IP routers were simply a cash cow to generate revenue for the development effort. The VC Board of Directors saw things differently when the money rolled in.) As finally built, it's the size of a two-drawer file cabinet. The XKL-1 CPU uses a couple of Altera FPGAs and a 2916 microsequencer as the microcode engine. Depending on instruction load, it is 1.8 to 2.5 times as fast as a KL-10. Systems Concepts started in the 1960s. Their first product, the SA-10, was a KA-10 I/O bus to IBM 360 bus-and-tag protocol converter, which allowed PDP-10 systems to use IBM disks (and tapes, I believe). Mike Leavitt and Stew Nelson, along with Pete Sampson, Fred Wright, Stu Grossman, and a couple of others whose names I've forgotten 20 years later, designed and built the SC-30M (code name Mars--as Fred put it in their marketing brochure, "Mars is a lot smaller than Jupiter, but it's a lot closer.") to be a KL-10 clone that ran faster. It was implemented in TTL instead of the KL-10's ECL, and was pipelined (something people-- even at XKL--think you can't do with the PDP-10 ISA) for greater throughput. It originally came with SA (bus-and-tag), CI, and EI (NIA-20 compatible Ethernet) interfaces; they got the MI (MASSBUS) working at our (Stanford LOTS) insistence. It maxed out at 8MW physical memory, but the work to take TOPS-20 from 4MW to 8MW was lost in a disk crash on their KI-10. It was about 2.2 to 2.4 times as fast as a KL-10. The SC-30M was designed as a multiprocessor system, to support Tops-10 SMP in a single box. They repackaged a uniprocessor version as the SC-25 (and as the Sc-20, with a half-speed clock). The big follow-on was the SC-40, with floating-point hardware that pushed the performance of FP operations to more than 10x of the KL-10; I don't know how it measured up in general instruction mix terms, as I never worked on one. No. The extensions are XKL proprietary as of this writing. Not silly at all. I'm glad that you asked. Rich Alderson Server Engineer, PDPplanet Project Vulcan, Inc. 505 5th Avenue S, Suite 900 Seattle, WA 98104 mailto:RichA at vulcan.com (206) 342-2239 (206) 465-2916 cell