WIthout interface cards, that’s all the early PDP-8’s and PDP-11’s did too. They had front panels with bat-handle switches and LED lights.
The big diff was that the Altair had a much lower price point, and a bus that was simple enough that hobby users could slap a card together. It really wasn’t much more than the signal/data lines on the 8080 brought out to lines on the bus.
What else the S-100 brought about was a clone industry once cards started shipping. When I was a kid, there were a dozen S-100 based computers out there in the “professional microcomputer” market, IMO because Ed Roberts created the S-100 and a couple of other people standardized it.
I worked on IMSAI machines at engineering school. Still have fond memories of them - even tho I thought CP/M was a complete rip-off of RT-11.
“I worked on IMSAI machines at engineering school. Still have fond memories of them - even tho I thought CP/M was a complete rip-off of RT-11.”
Actually, much earlier than that - CP/M looks a lot and is structured a lot like OS/8, the operating system of the PDP-8 computer, which had been around since 1965 or so. Considering that minicomputers of that era were so resource-poor in terms of memory and speed, this was a good place for microcomputers, also limited in both of those areas to start.