I am using the Xteink X4 as my primary e-reader now-a-days. Simple ESP32 microcontroller. Plastic+glass shell with an e-ink screen. MicroSD card works like a cache. Battery lasts for weeks. Works great.
Don't get me wrong. I like modern CPUs with huge caches and incredible power, but you do not need this for most devices. Also leads to lazy programming practices and calculators consuming hundreds of megabytes of RAM.
Caveat: 60p RP2350 microcontroller on a board that sells for $40 and has 8MB of RAM (as opposed to the 520K that the RP2350 comes with). But that is only needed for Photoshop. The 520K is more than enough to emulate the Mac 128K.
I'm reminded that chips like the Intel 8080 and Motorola 6800 were not intended to be general-purpose computers, and were originally designed mostly to be embedded controllers and as building blocks for "real" computers like terminal and disk controllers.
I suppose in principle the RPi Pico could self-host its own OS and devel environment. 520 KB of RAM in the old days was plenty to fit an OS and compiler. No MMU so no paging though.
> I suppose in principle the RPi Pico could self-host its own OS and devel environment. 520 KB of RAM in the old days was plenty to fit an OS and compiler.
With two cheap PSRAM chips and a bit of trickery, you can upgrade that to 32(.5) MB, which is certainly enough to run a small OS.
In principle you can add even more memory with bank switching, but 32 MB is the limit for a flat address space.
For a more capable but still underpowered computer, I found Antix can run well in almost 20year old hardware - I use it in an EEEPC 4G Surf, but I modded it to have more storage recently.
Don't get me wrong. I like modern CPUs with huge caches and incredible power, but you do not need this for most devices. Also leads to lazy programming practices and calculators consuming hundreds of megabytes of RAM.
I suppose in principle the RPi Pico could self-host its own OS and devel environment. 520 KB of RAM in the old days was plenty to fit an OS and compiler. No MMU so no paging though.
With two cheap PSRAM chips and a bit of trickery, you can upgrade that to 32(.5) MB, which is certainly enough to run a small OS.
In principle you can add even more memory with bank switching, but 32 MB is the limit for a flat address space.