Basically, I am looking for some form of non-volatile memory – which is not an SD card. Orange Pi and others have it, but I can’t find a suitable Raspberry Pi.
Did I miss one? Are there any rumours of one in future? Could I add some via a hat?
I don’t want to use an external harddrive because of space constraints. However, I would consider an extremely small USB stick, if there is such a thing, just so long as I can read/write.
I do not need a file system, though can live with it. I am happy enough with a contiguous memory mapped array, where I write some code to read/write X bytes from address Y (which is easy enough to simulate in a file system).
I don’t need a high data transfer rate; we are speaking of a few kilobytes every few minutes at most.
If there is not a Pi specific solution, then I will close this question and ask over at hardware recommendations for a physically small USB device.