<I am not saying that the Sphere papers are of real historical significance <- the company simply did not last very long, and in my opinion, was a <producer of junk - but anything Sphere is very rare. Sphere was an example of some of the shadier companies, all flash and very little fire. At the time I'd wondered if they had shipped anything at all. In all I think they represented less than a 8month piece of the industry that had some con artists as well as serious vendors. <> I guess it's time for one of those questions I still don't have a good <> answer for. Where the foo has all the SS-50 stuff gone? Or is it still <> hiding? Or is it just not here in Sillycon Valley? SS50 was fairly popular and tended to build up into solid systems. The people that used them were not hardware hacks and tended more towards software and applications for their box. I have no idea where they went save for if I tripped over one I'd keep it as they were good machines. <I have seen very little as well. That says something, as the boards tend <to really stick out in the crowd. They never reached the popularity of the <S-100 stuff, and was probably made in quantities much smaller than just <about every other bus. I don't know. S100 was bigger, no question. SS50 was actually better early on. The problem with SS50 generally was it was 6800 cpu and that was not fast nor was it easy to plug non motorola cpus in to the bus. SS50 went two others that would interface to that bus(more or less) but any of the 8080/8085/z80/8088 types had bus timing and signals that were radically different. S100 was less tied to the CPU despite it originating with 8080. Early on 6800 cpu was easy to get into as Moto had the big book for $25 and it had every bit of hardware and software info you could want. It's limitation was the fastest 6800 was 2mhz and you either liked it or didn't. Also I feel motos lack of timly follow on in the form of faster 6800s and far later 6809 and later still 68000 didn't help. Some of the AMI SBCs were pretty nice and the 6800 market had a greater selection of SBCs at attractive prices including the moto 6800d1/d2 kits. The other s100 cpus of the time were 9900, T-11(marinechip systems s100 pdp-11), 1802, sc/mp(1&II), Alpha micro(wd13 chipset), 6809, 68008/68000, 8088/6, 80188/6, 80286, z8000, NS16016(32032). I've also seen 8049, 8051 and 2900 bit slice used for s100 cpus. This diversity kept s100 going longer and offered choices that could please those that asprired to one cpu over another. Also other popular machines had companies offering s100 adators, KIM, TRS80 being two I remember. It backed up the idea that no one manufacturer could supply the diverse demand for interfaces to their systems that having a common bus(s100) could supply. I may add that S100 went beyond cpu, memory, serial, parallel and disks. The availability of prom/eprom/pal programmers, A/D, D/A, opto and relay I/Os, Voice, display, networks was extensive. This al la carte offering made pure one manufacturer s100 systems rare as multiple vendor systems integration was common. I may add you also had the <at least> three commercial busses STD(z80), multibus intel processors(and z80) and VME bus which was motorola cpus. It highlights the fundemental differences between the motorola and intel designs. The 6502 is fundamentally motorola interface and bus FYI. The Apple by default also created an aftermarket bus standard for the slots it had. Other busses that lasted a moment: Altair 680 (6800 based), digital group, ti99/4a expansion. There were others I'm sure. Allison