[spicybright]

> Writing a new OS is enough work, nobody would have time to also write file systems, compilers, a shell, a text editor, an Internet browser and so on.

> So there must exist some translation layer also for device drivers, maybe by running them in a virtual machine.

> ... but rewriting all the device drivers that could be needed would take years, so it is important to implement a way to reuse the existing device drivers.

I'd think most people making a hobby OS specifically want to do these things.

I also think most don't care about wide hardware compatibility.

[adrian_b]

Even if you do not want the new OS to run on anything else but your own laptop, that still needs a huge amount of drivers, for PCIe, USB, Ethernet, WiFi, Bluetooth, TCP/IP, NVME, keyboard / mouse / trackpad, sound, GPU, sensors, power management, ACPI and so on.

The volume of work for rewriting all these is many times larger than writing from scratch all the core of a new OS.

Rewriting them requires studying a huge amount of documentation and making experiments for the cases that are not clear. Most of this work is unlikely to present much interest for someone who wants to create an original OS, so avoiding most of it is the more likely way leading to a usable OS.

[spicybright]

I think you're still missing the point here.

Not every hobby OS needs or even wants networking, gpu support, even storage I/O, etc. See TempleOS.

The goal typically isn't to make a fully featured OS.

[adrian_b]

If you do not want those features, that means that the OS is not intended to be used on a personal computer, but only on an embedded computer.

For dedicated embedded computers, the purpose for an OS becomes completely different and compatibility with anything does not matter any more.

Not only personal computers cannot be used without a huge amount of device drivers, but even for a very simple server, e.g. an Internet gateway/router/firewall or a NAS server, the amount of work for writing the device drivers, the file systems and the networking part would be much more work than writing the core of a new OS.

Only for embedded computers the work needed for device drivers can be smaller than for the base operating system.

[eggy]

You hit it on the head: The point is purely for fun and learning. I want to learn as much as I can by rebuilding apps from scratch, etc. I had my first computer in 1977/78, a Commodore PET 2001, followed by a Vic-20, so if I can duplicate the bare system I had them and a PL to create apps, I am back where I started - having fun with computers!