This was a big deal back then. The KIM-1 came with 1K of RAM, which was a lot more than the 256 bytes that the Altair came with. But it was still pretty small; more memory was necessary to write any good programs. So in the summer of 1977 I purchased a 4K RAM kit. It cost $150, which translates to about $800 in 2023. Take a moment to contemplate this figure. Amazon.com has a 256 GB thumb drive for $25. Thus, my 4K RAM kit cost $0.20 per byte. The thumb drive costs about $0.000001 per byte. That’s 20 million times cheaper than my 4K RAM kit. And remember, I got only a kit for my money. I had to solder about 700 solder connections to build it. There was a small slip of paper inserted into the kit, informing me that, due to an error on the manufacturer’s part, I was required to add several additional wires and a resistor at designated locations. Ah, the good old days.
Here’s what the board looked like:
Please ignore the absence of the two screws holding the heat sinks to the voltage regulators on the right side; those screws secured the board to the plexiglas and had to be removed to permit me to photograph the front side of the board. I don’t know why the five sockets in the lower left are empty. That was just the way things were back then.