NT 4 embedded has a disk image that's like 10 MB, which gives me a gloriously cursed idea for a website that's still smaller than your average site today
I actually worked on this yesterday, and I'm probably going to use XP Embedded instead, because
a) I surprisingly actually have a runtime license for it, so you don't have to sit through the FBA preparing the OS to avoid the evaluation time bomb
b) compiling software for XP is much easier than compiling software for NT 4
(The embedded versions have two licenses, one for the tooling, which I have access to through work's Visual Studio subscription, and the runtime one, which is supposed to be specific to a product, and thus requires you to buy it separately - the runtime serial can be dumped from any image, so you can just get it from a thin client of the appropriate era)
I also now understand why Windows 10 is built from individual components with dependencies now - it's literally what they've done for Embedded since the early days, except instead of untangling things after the fact, they keep things compartmentalized from the get go.
This also makes odd dependencies more obvious, like how in XP Embedded adding a serial device driver adds modem support, which adds a ton of GUI stuff
or how adding Notepad adds Internet Explorer
(Notepad pulls in the rest of the accessories like Paint, which pulls in the Help renderer, which pulls in MSHTML, which pulls in Internet Explorer)
@ChlorideCull an entire website that hosts it's own server software on your computer just to display a hello world message
@EeveeEuphoria people have actually ported virtual machine software to browsers
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