The Natural Philosopher  wrote:
>
> Looking at my 'I only do one thing' Pi running 94 different processes,
> realistically how many of them do I need? And how could I get rid of them?
>
> I want to examine the pi as a reasonably real-time signal processing unit.
>
> I don't need disk access except to load the code. I may not need network
> access. I don't need logging. I sure don't need systemd. I don't need a
> gui.

Try PiCore, it's as stripped-down as Linux gets for the Pi. Boots
_way_ quicker than RPi OS on my Pi Zeros. No GUI, or systemd, no
disk access (runs in RAM). if you want to disable hardware
drivers, you can do that in config.txt (as you can in Raspberry Pi
OS).
http://www.tinycorelinux.net/ports.html

> I just want to run one high priority daemon and one lower priority
> demon, with shared memory between them...is there something simpler than
> Linux? More like e.g. DOS?

There are various Bare-Metal environments, such as:
https://github.com/rsta2/circle
http://www.stevebate.net/chibios-rpi/GettingStarted.html

--
__          __
#_ < |\| |< _#

--- SoupGate-Win32 v1.05