SIIG MiniSys S286 Small Form Factor PC
users.glitchwrks.com
users.glitchwrks.com
Compared to just about anything else at the time, it was surreal that it could even exist. The closest I know of was the HP48G calculator, which was completely underpowered compared to the Atari.
Amazing crew though, they were really ahead of their time. TI also had a bunch of programmable calculators but those weren't really computers. (Ti 57, 58, 59).
And then there was the Sharp https://en.wikipedia.org/wiki/Sharp_PC-1211 released in 1980, which probably also qualifies for the title (I still have one in mint condition).
You could compile DOS programs in for instane C and run them on the Atari, so it could really be a portable workstation if that was your thing!
If I recall correctly, the C compiler from Turbo C ran on it directly, so you could even develop directly on it.
It's a very charming device. I used to own one in the mid-to-late 90s as well that I got used from the local computer store in my small town.
edit & update: answer is yes! Wikipedia article confirms it in the "popular culture" section
I mean, it was out of my budget by far, but a few kids in my school could easily have gotten it if they knew and wanted.
Here's one. I had only the central unit, mine had two floppy drives. https://tinkerdifferent.com/threads/introducing-the-flytech-...
The photos in the auction show some of the internal details and the array of ports on the backplate. It's definitely a cute little PC.