[Someone]

You could hook up a Mac to the internet in 1985-ish, transferring files using telnet.

Mac OS still ships with BinHex (https://en.m.wikipedia.org/wiki/BinHex), I think, so for Macs, that might already be the simplest way to exchange data between an early Mac and a modern machine (even if you have a floppy drive, does it read Mac disks?)

Edit: maybe my memory is of, and it was direct dial-up to another machine, not across the internet. NCSA Telnet (https://en.wikipedia.org/wiki/NCSA_Telnet) supported TCP/IP before the OS did (yes, that was possible. I don’t know whether you still could do that on a modern system), though, so who knows?

[swiftcoder]

> supported TCP/IP before the OS did (yes, that was possible. I don’t know whether you still could do that on a modern system), though, so who knows?

In general you can. If the OS lets you open raw sockets, you can implement TCP and all yourself in userspace. Although in those days, I'm guessing it was actually implementing the entire AT modem stack too, and just driving the modem directly via a serial port.

[jfrunyon]

> You could hook up a Mac to the internet in 1985-ish, transferring files using telnet.

I'm sure you could. In 1985-ish.

How much of the required hardware still exists? How much of the required software can you find? Is that software (or another version of it) also compatible with your modern computer? etc.