Re: Linux. 16MB could run a reasonable X environment in the early 90s. I sometimes ran it in 8, but that was kind of marginal. Maybe you'd call it very constrained in not including Gnome or KDE, but it didn't feel that way.
* On 1998 I ran SuSE 5.3 with KDE and GNOME (even Gnome 1 over KDE 1.x !!) on a machine with 16 or 32 MiB of RAM and a AMD 486DX5 at 133Mhz . And was working fine.