Confused about Network connection stuff in a guest OS

[Ozymandias]

So, as some people may (or may not know), I had recently attempted to establish a network connection for a virtual MS-DOS 6.22. Apparently, I had some success with it, but it seems to lack the packet drivers needed to... uh, do internety thingies? If that is the issue, I wouldn't know. Anyway, after that experience, I took a break from MS-DOS (I'll return to you one of these days), and decided to muck around with some other operating systems. I became fascinated by Linux recently, and at first I installed Ubuntu, and then I installed Antergos. I noticed a big difference right off the bat: Both the Ubuntu and Antergos were automatically networked and able to use the internet connection.

I'll be honest, I am aware that MS-DOS was never built with networking in mind, since that was in 1994. I understand that much. But what I am more confused about is why I didn't have to set anything up in my other more modern guest Operating Systems to be able to network? Like, I was honestly expecting that I would need to spend some time setting up drivers and software and such just to get an internet connection. Even then, whether that is the case or not, I don't know how a virtual machine actually communicates with a host machine. I know that my real legitimate machine connects to the internet through my phone tether setup.I had to install a driver for that and the appropriate software so I could connect.

I've noticed that with DOS and my attempt to network, after following some guides, I had to set the network adapter to PCnet-FAST II (Bridged Adapter, PdaNet Broadband Adapter). Although only partially successful with networking, I had to do all of that manually. Meanwhile, my Linux guests seemed to have automatically connected to Intel PRO/1000 MT Desktop (NAT). I literally did not have to set anything up or install anything for those, they automatically set themselves up. So, what exactly are those adapters? What do they do and how do they work with the virtual interface? I'm guessing they're just simulated hardware of sorts, but if that's the case, how come my DOS didn't do that? Is that dependent on the specific OS that I install or dependent on VBox itself?

[socratis]

since that was in 1994

I didn't have to set anything up in my other more modern guest

Is that dependent on the specific OS that I install or dependent on VBox itself?

You answered your own questions. For a some basics on the hardware/software interaction, read https://en.wikipedia.org/wiki/Plug_and_play

But these are general computer questions I'm afraid, that apply to actual real hardware/software not specifically VirtualBox, so do yourself a favor and try to find some good tutorials on the basics of computers.

[mpack]

I am pointing out the obvious, but the purpose of an Operating System is to operate things for you. A 1994 OS can't operate your Internet connection because it doesn't know the Internet from your elbow. In practice you need to be using XP or later if you want Internet, and even in the XP case you have to install a more modern browser such as Firefox. Obviously if you install an OS from this year then naturally it has everything it needs to cover a task as important as 2016 style Internet comms.