> Anecdotally, it doesn't seem to be possible to start a mainstream Linux distribution w/ less than about 128MB of RAM, perhaps due to the initramfs-based boot that's ubiquitous nowadays.
Depends on what you call a mainstream Linux distro. Maybe if you only include "desktop" style Linux distributions, which don't tend to be the most mainstream use for Linux.
dd-wrt is extremely popular. It generally requires somewhere between 2-4MB Flash, and the smallest amount of RAM I saw when going through the supported router list was 8MB.
U-Boot is an extremely popular Linux bootloader, that generally runs the mainline ucLinux kernel, which has support for STM32 microcontrollers, where you'll be looking at much, much less RAM. More likely to be measured in kilobytes than megabytes. It could be argued this isn't complete enough to be called a distribution.
> And a i686 class CPU is needed.
Not at all. Debian, Ubuntu, Gentoo, Arch, all have ARM based versions, before you go diving into what else they support. (Keep reading if you meant the kind of x86)
And whilst some have dropped the 486 (Debian even dropped the 586 in 2016 [3]), Gentoo still supports it if you follow along with the mostly manual installation guide. (Though this [0] spells it out in a much easier way.)
However, running Linux on a 386 is difficult and unsupported (the kernel dropped support in 2012 [2]), NetBSD still actively maintains a port. [1]
As to the 286... Linux never supported it as far as I know.
So the upshot is, if you have a 386, 486, or 586 you can still run Gentoo.
Depends on what you call a mainstream Linux distro. Maybe if you only include "desktop" style Linux distributions, which don't tend to be the most mainstream use for Linux.
dd-wrt is extremely popular. It generally requires somewhere between 2-4MB Flash, and the smallest amount of RAM I saw when going through the supported router list was 8MB.
U-Boot is an extremely popular Linux bootloader, that generally runs the mainline ucLinux kernel, which has support for STM32 microcontrollers, where you'll be looking at much, much less RAM. More likely to be measured in kilobytes than megabytes. It could be argued this isn't complete enough to be called a distribution.
> And a i686 class CPU is needed.
Not at all. Debian, Ubuntu, Gentoo, Arch, all have ARM based versions, before you go diving into what else they support. (Keep reading if you meant the kind of x86)
And whilst some have dropped the 486 (Debian even dropped the 586 in 2016 [3]), Gentoo still supports it if you follow along with the mostly manual installation guide. (Though this [0] spells it out in a much easier way.)
However, running Linux on a 386 is difficult and unsupported (the kernel dropped support in 2012 [2]), NetBSD still actively maintains a port. [1]
As to the 286... Linux never supported it as far as I know.
So the upshot is, if you have a 386, 486, or 586 you can still run Gentoo.
[0] https://github.com/yeokm1/gentoo-on-486/
[1] https://wiki.netbsd.org/ports/i386/
[2] https://www.pcworld.com/article/2020196/linux-3-8-will-drop-...
[3] https://distrowatch.com/dwres.php?resource=showheadline&stor...