Smallest linux computer I've seen was Transcend SD card (the wifi one). There are more manufacturers and I think Electric imp uses the same chipset.
https://hackaday.com/2016/06/30/transcend-wifi-sd-card-is-a-...
which links this article:
https://jamesone111.wordpress.com/2014/03/19/exploring-the-t...
So this is a Linux server in the size of an SD-Card that has 16 GB of storage. And Wifi. And lets clients connect to download whatever's on them.
I was thinking, wow, this must be some pro photography thing costing like $399 or something.
The cost (given in the second article) is £25 (which is $32.19 today.)
That is pretty cheap for a tiny Linux server of this size. With WIFI.
And it made the rounds 5 years ago: https://hn.algolia.com/?query=Transcend%20Wifi-SD%20card&sor...
What is the world coming to.
By the way here is the one where HN discussed it the most:
https://news.ycombinator.com/item?id=7647434
And note the comment that Transcend released the firmware (though that link is offline today.)
However I guess there really just aren't all that many use cases for this kind of a server. Or maybe it has been superseded? One page[1] lists it as weighing just 2 grams, compared with the weight of 2.5 grams for a U.S. penny. That's gotta have some sort of applications. Why isn't this more popular at $30, or what are people using instead? Is it like, impossible to get any ports out of it, even a single serial debugging port via soldering, so you can't connect it to anything else?
It just seems so hackable!
[1] https://www.extremedeals.com.ph/products/transcend-16gb-wifi...
http://dmitry.gr/index.php?r=05.Projects&proj=15&proj=15.%20...
At first I thought it referred to just 3 MB of RAM (ouch!!) - but it has 32 MB. That's enough to do quite a bit in a stripped-down embedded Linux.
To quote that page:
>An exciting time indeed - now this WiFiSD card is a perfectly working ARMv5 computer with a kernel and ramdisk we can build, and 16GB of storage. Pity it only has 32MB of RAM. Well, we do have ability to modify the kernel now. I added support for swap, ext4, sysfs, loop, and a few other modern conveniences we all know and love. Once again the card booted. Now I was able to swapon a file on the SD card, loop-mount a 2GB ext4 filesystem and chroot into a version of ubuntu in there. Once inside, it is the nice and comfy environment you'd expect. I was able to bring up sshd with X-forwarding, and even run firefox on the card (it was slow). Modifying the card's boot scripts again, I tried to get it to do all this on boot and succeeded. SWEET!
....for about $30 and in the size of an SD-card and weighing less than a penny. With WIFI.