Linux was first developed by Linus on an old .386 system, way back in 1991, and now that cord has been cut, and .386 CPUs are no longer supported:
From the comments:
Pull “Nuke 386-DX/SX support” from Ingo Molnar:
“This tree removes ancient-386-CPUs support and thus zaps quite a bit
24 files changed, 56 insertions(+), 425 deletions(-)
… which complexity has plagued us with extra work whenever we wanted
to change SMP primitives, for years.
Unfortunately there’s a nostalgic cost: your old original 386 DX33
system from early 1991 won’t be able to boot modern Linux kernels
I’m not sentimental. Good riddance.
My first ‘home’ Linux system – in 1997 – was an HP Vectra 486 – 50Mhz CPU, with 512k memory, and a 1.2GB disk drive. Red Hat 4.2 – Kernel 2.0.36..(IIRC..). I remember having to patch the later 2.2 kernel, to get USB support, using a patch ‘backported’ from the development version 2.3..
Robert Gadsdon. December 12th, 2012..