You end up with an OS kernel that talks Linux/Win32 and takes on a lot of compat code, protocols, and other paradigms.
I wonder what a hobby OS would have looked like it if it assumed nothing, that is, as a thought experiment, as if aliens on another planet invented computing and started writing OSes from scratch. Imagine we discover software from another planet that would not even work with 8-bit bytes, for instance.
(If you want to communicate with other computers) You probably do want to speak IP, but if you want to do all the work, you don't need to use BSD sockets.
POSIX and other such things will let you use more of other people's software... but that's a choice.
You can also do a lot of reuse if you just want to focus on some parts. There's no need to write a bootloader unless you want to. You can pull in lwIP for the IP stack. You can do a lot of interesting (I think) things with barely any userland if you want.
If it's supposed to be a general purpose OS, you end up looking a lot like existing general purpose OSes though, cause it's hard to build everything and the closer you get to existing OSes, the more existing software you can leverage.
If you only want to run a subset of existing software, you might not need to cover that many of the syscalls from whatever OS it was targetted at. My hobby OS runs one specific FreeBSD executable, and it doesn't take that many syscalls to do it.
> Imagine we discover software from another planet that would not even work with 8-bit bytes, for instance.
8-bit bytes didn't become fully dominant until maybe the 1970s. It's a bit hard to find software older than that, but it's around somewhere.
You could use STREAMS!
http://herpolhode.com/rob/utah2000.pdf
I’d love to see a new operating system that explores radically different APIs for applications. The trouble is writing an operating system is a large effort. Barring market effects, OS has to be heads-and-shoulders better than existing ones in order to convince application developers to write software for it. Windows, macOS, and Linux are good enough for most people, even techies. Additionally, it is often easier to modify an existing operating system such as Linux than to go through the trouble of writing a brand new operating system.
Linux/BSD have massive hardware support, where a new OS needs to start from scratch. The same is true of software support: a new OS that truly has new primitives either adds a POSIX layer (and all POSIX-like software can't benefit from many of its improvements).
Even once you get past hardware and software support (both herculean tasks) performance needs years of hard work to be comparable to mainstream OSs.
And don't even get me started on the ever-growing complexity in standard protocols: HTTP2/3? QUIC? TLS? All "doable", but also huge sinks for time and effort when you already have a huge list of things to deal with.
There's lots of stuff that was around in the 1960s that became dead-ends because everybody piled in on another way of doing something, and then things got optimised for that way, then every other way was less performant, and soon the lucky one way became the only way.
I've never really had much time to explore these early ideas from well before I was born whilst working, but definitely think it'd be a fun way to spend my time when I eventually retire - to try to recreate some of the stuff from that era that got forgotten and see what it could be developed into nowadays.
For example, just watch Douglas Engelbart's 1968 demo [1] for some ideas - some of the things presented in that took decades before it was rediscovered and implemented on systems available outside of research environments.
But, since you can delegate a lot of the grunt work to AI now, I think it becomes a lot easier to have it either, write the legacy stuff for you, or port software over. That way you still have the ability to design a system with the things you think would be interesting, while still having some possibility of running "real" software under it.
There are some hobby OS projects that do this. The best known example is Terry Davis' TempleOS.
https://en.wikipedia.org/wiki/TempleOS
If you only want to please yourself, you can dispense with all that legacy stuff. You can stay busy and enjoy yourself in your own world. Some of the hobby OS listed here look like they might be standalone worlds:
I love the idea of Wine acting as the universal interface that lets you run windows apps wherever the heck you want.
And of course, this is just an escape hatch. You can support Wine and also support "native" apps which are optimized for your custom OS.
I've been working on my own hobby OS for half a decade. It does a lot less, but it has helped me realize that we can remove much of the complexity of a generic mainstream OS while still meeting our personal computing needs. I know I'm just poorly reinventing something between DOS and Unix/Plan 9 in an extremely limited fashion, but it's absolutely perfect for experimentation!
Pretty impressive, you've gotten much farther than I ever did (I didn't have the patience to implement all the borderline boilerplate an OS needs).
I remember all the things I needed to implement before reaching userspace, it's a lot indeed. After that it gets easier because every new change is motivated by a specific smaller goal like supporting the network card of a new laptop, or adding sounds to the emulator, or adding one more syscall or device file. You get rewarded by new capabilities after each addition.
https://wiki.batocera.org/systems:windows#folder_compression
The DOS heyday was the 1980s.
No officially-released version of DOS contains generic CD-ROM drivers; the last few DOSes (MS-DOS 6.x, DR-DOS 6/7) contain the redirector (`MSCDEX.EXE` or equivalent) but not the device driver.
From 1992, Windows 3.1 rapidly took over.
The first mass-market CD-ROM drives were the mid-1990s, and ATAPI CDs that could attach to an EIDE interface only became common in the latter half of the 1990s, when Windows 95 was the default PC OS.
Microsoft never shipped any version of Windows 3.x on CD; I used to have a Gateway 2000 WfWg3.11 CD in my travelling toolkit, just in case. Windows 95 originally shipped on 13 1.4MB floppies.
On that note, FreeDOS does support CD-ROM.
A ROM is a binary blob that some executable accepts as input and interprets, the executable being the emulator, which simulates the target hardware well enough that the ROM's machine code runs as if it were on the original silicon.