Legacy PC design misery (2009)

Honestly, I think the only program that ever relied upon the A20 gate was MS-DOS. I say this from having perused the MS-DOS source code Microsoft has released. And this reliance on A20 was due to an attempt to remain backwards compatible with CP-M, which I think was only ever really needed (if ever) for MS-DOS 1.0. Sigh.

Links to https://aeb.win.tue.nl/linux/kbd/A20.html which is also an amazing read.

(2009). Interesting but for a bit I was out here wondering: they're actually running Fedora on that hardware? Well I guess I've ran it on strange old hardware too. It only hit me when I read the bit about grub2 at the end, because of course, Fedora has been using it for a while now.

I have Kohjinsha SA5 and it got some tricks up its sleeve too: using Geode LX is from 2003, it has MMX and 3DNow! but not SSE, which apparently breaks quite a lot of software expectations.

Fun piece of history. The tied A20 was the way that the original Xbox was hacked.