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Can anyone explain to me how these things work? I was expecting some sort of memory chip on a small board.

I always thought, from piecing together different information, that an SD card is basically a chip in a plastic housing with the bare minimum of circuitry to the interface.

Patent:

https://patents.google.com/patent/US20080235939A1/en

Not sure either of these help:

https://youtu.be/VhxKLbvz7so

https://youtu.be/YtBysgPOKx4

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Completely correct.
Up to a few years ago memory cards had a minimum of two chips. One for storage and the peripheral interface controller. With the 8, 6, 5, and 4um interface we have gotten down to a single chip.

Even uSD and mSD cards with a single “chip” they are actually a multi chip carrier (MCC) which puts two chips into a single form.
Today Samsung has managed to put it all into a single “chip” which.

To over simplify
Keep n mind solid state storage is nothing more than the equivalent of a capacitor collection or battery pack.
Binary data is stored as charged cells and non-charged cells.

If you were to open a micro SD card, removing the plastic, you find a chip on PCB. But, go further and crack that chip open horizontally, you’ll see two distinct regions. The larger one is storage; the smaller the controller.
That controller, can be one of two types. A hardware control actually uses something beyond the serial bus to handle the storage. Often with encryption and levelling.
A software controller tells the computing device: I’m serial access storage! Feel free to abuse me since I’m just a dumb floppy.

Most usb sticks use the MSD command and nothing more. A microSD has more instructions in the controller than the early CPUs did.

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Now that is just interesting. Its just amazing how far technology has came just since I was a little kid. One thing that still puzzles me is a fax machine, the first time I ever seen one was in the early 80’s. You just put a piece of paper in that dude and punch in the number and a short time later it prints off across town, or another town across the country. Looking at things now I wonder how we had the technology to shove a piece of paper in a phone (fax) line and make it go to another machine and print. But yet PC, cell phones and satellite tv would be nearly some 15 to 20 years later.

When you think of fax machines, how they work, it’s surprising it took so long to get them.
Photo scanning fax existed since The end of WWII in some degree of working.

Pre colour: they all did the same thing. Compare black vs white. The tones over the wire are literally black or white dot.
By the time Digital impression faxing reached us in the 1980s the signaling had grown to a modified version of LZ compression. The number of dots of dark before the space.

Transmitting visual data over wires, our fax machine, was invented in the late 1800s.
Following WWI this developed into over the air radio.
In the early days of WWII the British used American navy operators to translate binary-esq beep codes into 4 shade black on white maps. Long before we entered the war.

Barcodes work on the same premise.

When you think of cell phones the misconception is to think of a computer in your hand.
Cell phones send data over radio waves in beep code. So technically that makes CB/Walkie tech cell phones. In a sense. So the late 40s.
Dedicated point to point was early 50s. What made the cell phone (80s) become it’s own class was the ability to send direct beam to a single addressable spot via targeted radio.

But the fax machine is nearly 140 years old. And we still use it.
Showing sometimes we really do get it right the first time!
:D

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