The Altair 8800 from MITS of Albuquerque, NM, was my first computer. It came as a kit and was initially called a "minicomputer" in 1975. It had 256 BYTES of memory, which would not be enough to store this review. The front panel (the icon has the 8080B) had 2 rows of switches and 2 rows of LED's. In simple terms the top row of switches controlled the address and data registers (memory) and the buttom the cpu (run, single step, input/output, write/read, etc).
After building the 8080, there was no operating system, no basic, no nothing. You would create your very simple "program" by flipping those switches and hoping to get a reaction, such as adding some binary numbers together. Eventually BASIC would become available along with 1k memory board. I had hooked this up to an ASR33 teletype machine and was able to finaly save and load programs using paper tape punched with holes.
It would be another year before a floppy was added, and you had to write your own assembler programs to make them work. When Gary Kidall released CP/M, it still required a lot of hours to get it to work and you had to "roll your own" BIOS (Basic Input / Output System) or "drivers" to get anything to work.
The first Apple computer would become available about a year and half later and also came in a kit. But it had BASIC built in and only had to be hooked up to a TV screen to make it work.
Interacting with CP/M was done on a paper printing terminal rather then "glass" dispaly. Eventually I got an ADM display.
When I first saw this I was hoping for a real simulator with functioning switches and controls, but, alas (as Jerry Pournellle would often say) it accomplished its goal of taking me down memory lane.