On Thu, Jan 22, 2015 at 3:42 PM, Alan Mackenzie <a...@muc.de> wrote: > Just as a data point, the last project I worked on was an automotive > system, whose controller was a 32-bit Power PC with 768k/64k code/data > flash, and 64k RAM. It did not run systemd! Rather than Linux, it ran > Autosar (a special, and somewhat wierd, OS specially for automotive > products).
I wonder how small linux can actually get in such a world, assuming you still needed the multitasking, drivers, etc (which would be the main benefits of running an OS vs just embedding a single program written in C that directly talks to the hardware). You can trim a lot of stuff out of linux that we all take for granted, but I'm not sure if you can really get it into the 100kb range. I couldn't really find hard numbers anywhere for the actual minimum RAM requirements for a linux that contains the minimum features needed to provide a bit of hardware support and run init with almost nothing else exposed but the system call interface (no need for /proc, devfs, /sys, and so on). It sounds like you're still talking hundreds of kilobytes to 1-2MB of RAM use in most cases. So, dedicated embedded kernels are likely to stay around for a while to come. -- Rich
