I had an entire lab of these when I was working on human to human mesh networking.

The Sharp Zaurus, is a very a PDA that ran Linux.. I think I had the SL-5500 around 2003. Maybe it was a year or two later.

Because they ran Linux they were great for research software.

I have no idea how I even knew they existed. Probably Slashdot.

The typo here is I first wrote "very early smartphone" and then remembered there was no phone part to it.

and looks like a thing that can be played by four people at a time

Ha! It was pretty huge but so is an iphone pro.

How many  people did you need to handle one? xD

Jelly, I had the Dell Axim. It ran Nethack like a champ.