[kragen]

I didn't learn about the CPU or the display until 02021, but apparently they've been around for quite a number of years. My notes in energy-autonomous-computing in Dernocua http://canonical.org/~kragen/dernocua/ on both the Ambiq chips and the memory LCDs date from July 02021, also three days apart.

For the Zorzpad's main nonvolatile storage my plan is to use bare SLC NAND Flash, but I'll have to write to it fairly slowly to get to my desired design lifetime. So my initial plan of a KeyKOS-like or EUMEL-like transparently persistent system with huge virtual memory is out the window.

If your limit is only the power budget, though, that approach seems like it might be within reach; the energy-autonomous-computing note I mentioned above has a table of memory types and their energy consumption, and if I didn't fuck up the calculations, NAND Flash only costs about 10 nJ per byte to write. So a full memory snapshot (384 KiB) every 30 seconds (104 kbps) would only cost about 130 μW, and if your Lisp (or other virtual machine) can keep track of what data is dirty, it should be a fraction of that.

I'm glad to hear my notes have already been useful to you! I'm sure yours will be for me, too. And thanks for the links to initrd's work! I somehow didn't know about it.